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# Temperature vs GHG concentrations

I entered parts of the discussion about temperature vs GHG concentrations which started in the forum discussion Global warming in the news into the Azimuth project at Global warming and GHG concentrations

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1.
edited February 2013

Only

Global warming and GHG concentrations refers to an ongoing increase in the global average annual temperature in comparision to concentrations of Green house gases (GHG)

sounds a bit strange to me. Is this meant to be a definition? (I understand the first half is the definition of Global warming)

Or do you mean "This page is about the increase in global average annual temperature in comparison to the rise in concentrations of GHG"?

Actually I would suggest to rename the page to something like "Does global warming lag or lead a rise in greenhouse gas concentration?" because that appears more accurate to me. Right now the title is somewhat general, even my attempts to write about the log forcing could actually fall under the present title.

Comment Source:Great that you started a page about this discussion! Only > Global warming and GHG concentrations refers to an ongoing increase in the global average annual temperature in comparision to concentrations of Green house gases (GHG) sounds a bit strange to me. Is this meant to be a definition? (I understand the first half is the definition of [[Global warming]]) Or do you mean "This page is about the increase in global average annual temperature in comparison to the rise in concentrations of GHG"? Actually I would suggest to rename the page to something like "Does global warming lag or lead a rise in greenhouse gas concentration?" because that appears more accurate to me. Right now the title is somewhat general, even my attempts to write about the log forcing could actually fall under the present title.
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edited February 2013

Only Global warming and GHG concentrations refers to an ongoing increase in the global average annual temperature in comparision to concentrations of Green house gases (GHG) sounds a bit strange to me. Is this meant to be a definition? (I understand the first half is the definition of Global warming)

oops yes that is from the global warming page. Thanks for pointing me out. I copied the header from the global warming page and changed it....however oversaw that sentence. It's changed now to:

Global warming and GHG concentrations refers a comparision of earth temperatures to concentrations of Green house gases (GHG).

.

Actually I would suggest to rename the page to something like “Does global warming lag or lead a rise in greenhouse gas concentration?” because that appears more accurate to me. Right now the title is somewhat general, even my attempts to write about the log forcing could actually fall under the present title.

Comment Source:>Only >Global warming and GHG concentrations refers to an ongoing increase in the global average annual temperature in comparision to concentrations of Green house gases (GHG) >sounds a bit strange to me. Is this meant to be a definition? (I understand the first half is the definition of Global warming) oops yes that is from the global warming page. Thanks for pointing me out. I copied the header from the global warming page and changed it....however oversaw that sentence. It's changed now to: >**Global warming and GHG concentrations** refers a comparision of earth temperatures to concentrations of Green house gases (GHG). . >Actually I would suggest to rename the page to something like “Does global warming lag or lead a rise in greenhouse gas concentration?” because that appears more accurate to me. Right now the title is somewhat general, even my attempts to write about the log forcing could actually fall under the present title. done, see: <a href="http://www.azimuthproject.org/azimuth/show/Global+warming+and+GHG+concentrations">http://www.azimuthproject.org/azimuth/show/Global+warming+and+GHG+concentrations</a>
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I restructured it a little bit. I removed the redirects from Global warming because that's already a page in its own right. I also removed an explicit link to my blog article in progress, I'll add it when it's finished.

If you want to refer to an existing page, just put the name between double straight brackets: [[ ]]

Comment Source:Hi Nad, I restructured it a little bit. I removed the redirects from Global warming because that's already a page in its own right. I also removed an explicit link to my blog article in progress, I'll add it when it's finished. If you want to refer to an existing page, just put the name between double straight brackets: [[ ]]
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Hello Frederic

I restructured it a little bit. I removed the redirects from Global warming because that’s already a page in its own right. I also removed an explicit link to my blog article in progress, I’ll add it when it’s finished.

Yes its good that you put the global warming page in the list.

If you want to refer to an existing page, just put the name between double straight brackets: [[ ]]

I know. However I prefer to use HTML instead of thinking about which wiki/forum syntax to use for which wiki or forum.

Comment Source:Hello Frederic >I restructured it a little bit. I removed the redirects from Global warming because that’s already a page in its own right. I also removed an explicit link to my blog article in progress, I’ll add it when it’s finished. Yes its good that you put the global warming page in the list. >If you want to refer to an existing page, just put the name between double straight brackets: [[ ]] I know. However I prefer to use HTML instead of thinking about which wiki/forum syntax to use for which wiki or forum.
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Just tried to run the Humlum R code but the R installer is rubbish. It sets the first of its ldpath to the install dir and then sticks hard-wired /usr/lib paths all over the place so they'll have to be edited on a non-root server like mine. Grrrr. Would anybody find it useful to run Humlum's code?

Comment Source:Just tried to run the Humlum R code but the R installer is rubbish. It sets the first of its ldpath to the install dir and then sticks hard-wired /usr/lib paths all over the place so they'll have to be edited on a non-root server like mine. Grrrr. Would anybody find it useful to run Humlum's code?
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I've tried to run the R script on my local box but get 404's (not found) for the data downloads. It's good to see if this stuff is reproducible. Is this worth pursuing?

Comment Source:I've tried to run the R script on my local box but get 404's (not found) for the data downloads. It's good to see if this stuff is reproducible. Is this worth pursuing?
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The script works fine on my Mac, but I don't see much point in replicating someone's refutation of a non-interesting paper.

Comment Source:The script works fine on my Mac, but I don't see much point in replicating someone's refutation of a non-interesting paper.
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edited March 2013

Nathan wrote in the global warming thread:

It looks like the R code first applies a 12-month smoothing filter to the data before computing differences. That is, the value for each month is replaced by the average of that month, the preceding 5 months, and the following 6 months. Then the smoothed data are differenced (i.e. differences between successive smooth months are computed). All the rest of the code in the diff12() function, including the rounding, are technical details to convert between year-month date formats.

thanks for looking at that unfortunately quite unreadable comment, I don't know why the XML didn't work. I had tried to cast my guesses about that Diff12 into a formula. And as you describe the formula, I guess you are also reluctant to cast formulas here in the comments.

Which line in the rcode does the 5 and 6 months averageing? Is it within the diff12 definition? (again in this unreadable comment )

The script works fine on my Mac, but I don’t see much point in replicating someone’s refutation of a non-interesting paper.

I was mostly confused by the realclimate answer, because as I understood they claim that they could reproduce the curves in the Humlum et al article. That is if I look at the curve of co2 concentrations (fig 1 in real climate article), which is looking rather highly symmetric (especially in contrast to the highly wiggly temperature curves) then I would expect that averaging and taking differences wouldnt disturb this symmetric "look", in particular I wouldn't expect to get a "wiggly" curve as the Diff12(co2) curve in the Humlum article or the green curve as that in fig 2. (of the real climate article) (but which (as I wrote in the unreadable comment) may not be the curve of diff12(co2) but that of the diff12(of one of the temperatures)).

So in short if real climate which critizes the Humlum et al paper gets the same Diff12(co2) curve then something (at least for me) unexpected happens and I would like to understand whats going on.

Jim wrote:

I’ve tried to run the R script on my local box but get 404’s (not found) for the data downloads. It’s good to see if this stuff is reproducible. Is this worth pursuing?

were you connected to the internet? the data is stored nonlocally:

Comment Source:Nathan wrote in the <a href="http://forum.azimuthproject.org/discussion/1163/global-warming-in-the-news/?Focus=8791#Comment_8791">global warming thread</a>: >It looks like the R code first applies a 12-month smoothing filter to the data before computing differences. That is, the value for each month is replaced by the average of that month, the preceding 5 months, and the following 6 months. Then the smoothed data are differenced (i.e. differences between successive smooth months are computed). All the rest of the code in the diff12() function, including the rounding, are technical details to convert between year-month date formats. thanks for looking at that <a href="http://forum.azimuthproject.org/discussion/1163/global-warming-in-the-news/?Focus=8783#Comment_8783">unfortunately quite unreadable comment</a>, I don't know why the XML didn't work. I had tried to cast my guesses about that Diff12 into a formula. And as you describe the formula, I guess you are also reluctant to cast formulas here in the comments. Which line in the rcode does the 5 and 6 months averageing? Is it within the diff12 definition? (<a href="http://forum.azimuthproject.org/discussion/1163/global-warming-in-the-news/?Focus=8783#Comment_8783">again in this unreadable comment</a> ) >The script works fine on my Mac, but I don’t see much point in replicating someone’s refutation of a non-interesting paper. I was mostly confused by the realclimate answer, because as I understood they claim that they could reproduce the curves in the Humlum et al article. That is if I look at the curve of co2 concentrations (<a href="http://www.realclimate.org/index.php/archives/2012/09/el-ninos-effect-onco2-causes-confusion/">fig 1 in real climate article</a>), which is looking rather highly symmetric (especially in contrast to the highly wiggly temperature curves) then I would expect that averaging and taking differences wouldnt disturb this symmetric "look", in particular I wouldn't expect to get a "wiggly" curve as the Diff12(co2) curve in the Humlum article or the green curve as that in fig 2. (of the real climate article) (but which (as I wrote in the unreadable comment) may not be the curve of diff12(co2) but that of the diff12(of one of the temperatures)). So in short if real climate which critizes the Humlum et al paper gets the same Diff12(co2) curve then something (at least for me) unexpected happens and I would like to understand whats going on. Jim wrote: >I’ve tried to run the R script on my local box but get 404’s (not found) for the data downloads. It’s good to see if this stuff is reproducible. Is this worth pursuing? were you connected to the internet? the data is stored nonlocally: hss2012 <- function(wfl=12,forcing=FALSE,HadCRUT4=FALSE,HadSST3=FALSE, ftp.co2="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt", ftp.hc3="http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt", ftp.hs2="http://www.cru.uea.ac.uk/cru/data/temperature/hadsst2gl.txt", ftp.CO2="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_gl.txt", ftp.hs3="http://www.metoffice.gov.uk/hadobs/hadsst3/data/TS_all_realisations.zip", ftp.hc4="http://www.metoffice.gov.uk/hadobs/hadcrut4/data/time_series/hadcrut4_monthly_ns_avg.txt")
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edited March 2013

Nathan, thanks for the time-saving steer. My first reaction was to want to know what you (and/or Tim Merlis if we ever acknowledge his existence) thought of the paper.

Comment Source:Nathan, thanks for the time-saving steer. My first reaction was to want to know what you (and/or [[Tim Merlis]] if we ever acknowledge his existence) thought of the paper. Nad, a 404 is a page not found but internet fine: temporary glitch possibly. I didn't bother trying to download them manually but thanks for the links; I knew about the uea docs but not the met office.
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edited March 2013

The line that does the averaging is:

if (!is.null(wfl)) x <- filter(x,rep(1,wfl)/wfl)

filter is a built-in R function to do weighted smoothing; here the weights are uniform (1/wfl, wfl=12) over a 12-month window.

The line that does the differencing is:

diff12[m,] <- diff(x[ii])

diff is another built-in R function.

The wiggles in the green curve from Fig. 2 don't surprise me given the CO2 curve in Fig. 1. The differencing pulls out all the interannual variability in the carbon cycle, which isn't nice and symmetric. (See also Renato Iturriaga's graphs, annually averaged.) But there may be more going on than what I described. I don't quite understand why the R code is iterating through months, whether it just has to do with how the data is formatted or if it's actually part of the analysis. I'd either have to pore through it in more detail or read the paper to understand what they're trying to do.

Comment Source:nad, The line that does the averaging is: if (!is.null(wfl)) x <- filter(x,rep(1,wfl)/wfl) filter is a built-in R function to do weighted smoothing; here the weights are uniform (1/wfl, wfl=12) over a 12-month window. The line that does the differencing is: diff12[m,] <- diff(x[ii]) diff is another built-in R function. The wiggles in the green curve from Fig. 2 don't surprise me given the CO2 curve in Fig. 1. The differencing pulls out all the interannual variability in the carbon cycle, which isn't nice and symmetric. (See also [Renato Iturriaga's graphs](http://johncarlosbaez.wordpress.com/2011/02/04/carbon-dioxide-puzzles/), annually averaged.) But there may be more going on than what I described. I don't quite understand why the R code is iterating through months, whether it just has to do with how the data is formatted or if it's actually part of the analysis. I'd either have to pore through it in more detail or read the paper to understand what they're trying to do.
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edited March 2013

Nathan you wrote:

It looks like the R code first applies a 12-month smoothing filter to the data before computing differences. That is, the value for each month is replaced by the average of that month, the preceding 5 months, and the following 6 months.

and

filter is a built-in R function to do weighted smoothing; here the weights are uniform (1/wfl, wfl=12) over a 12-month window.

I interpreted "the value for each month is replaced by the average of that month" as the typo-corrected sentence: "the values for each month are replaced by the average of the values of that month", because if there is no typo then what should be the "average of a month" in this context??

So this would mean I sum over the values in a month and divide by the number of values. But then what does this built in "filter" in this r-code? It sounds as if it takes the 12 averages of the 12 months, sums them up and divides them by 12. Yes, no?

I think there should be a formula in the articles. The result should also be reproducable with other software than this r-code and this means in particular without the need to "reverse engineer" the formula from the r-code. I mean from what I understood sofar - we are talking here about sums and differences and may be taking some fractions of a set of real values. It looks to me as if one should be able to do this with any simple calculator or even by hand, but I may of course oversee something.

I couldn't make sense of Renato Iturriaga's graphs, as I couldnt find anywhere a readable description of how he derived them.

Comment Source:Nathan you wrote: >It looks like the R code first applies a 12-month smoothing filter to the data before computing differences. That is, the value for each month is replaced by the average of that month, the preceding 5 months, and the following 6 months. and >filter is a built-in R function to do weighted smoothing; here the weights are uniform (1/wfl, wfl=12) over a 12-month window. I interpreted "the value for each month is replaced by the average of that month" as the typo-corrected sentence: "the values for each month are replaced by the average of the values of that month", because if there is no typo then what should be the "average of a month" in this context?? So this would mean I sum over the values in a month and divide by the number of values. But then what does this built in "filter" in this r-code? It sounds as if it takes the 12 averages of the 12 months, sums them up and divides them by 12. Yes, no? I think there should be a formula in the articles. The result should also be reproducable with other software than this r-code and this means in particular without the need to "reverse engineer" the formula from the r-code. I mean from what I understood sofar - we are talking here about sums and differences and may be taking some fractions of a set of real values. It looks to me as if one should be able to do this with any simple calculator or even by hand, but I may of course oversee something. I couldn't make sense of Renato Iturriaga's graphs, as I couldnt find anywhere a readable description of how he derived them.
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12.

The filter code takes the value for a month and replaces it with a 12-month average. Specifically, it averages over the value for the month being replaced, the values for the preceding 5 months, and for the following 6 months.

Comment Source:The filter code takes the value for a month and replaces it with a 12-month average. Specifically, it averages over the value for the month being replaced, the values for the preceding 5 months, and for the following 6 months.
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edited March 2013

Nathan wrote:

The filter code takes the value for a month and replaces it with a 12-month average. Specifically, it averages over the value for the month being replaced, the values for the preceding 5 months, and for the following 6 months.

So if $q= (q_1, q_2,\ldots,q_N)$ is a list of time ordered monthly measurement values

then

$filter(q_i)= 1/12*\sum_{j=0}^{11} q_{i-5+j}$

Is that correct?

And $Diff12(q_i)$ would then be filter $(q_{i+1})-filter(q_i)$ or would it be $filter(q_{i})-filter(q_{i-1})$?

But that would then just be the yearly difference in monthly concentrations shifted by e.g. 5 months, i.e. in the first case

$q_{i+7}-q_{i-5} = q_{i-5 + 12} - q_{i-5}$

divided by 12 .....If I didnt miscalculated something in my head.

So by looking at the co2 curve of concentrations, which looks periodic in year, this difference looks more like being a constant or maybe eventually slightly increasing. So I'd expect a slightly wiggly straight line on a first glance for the diff12 curve of the co2 concentrations. In particular if I look at fig 1 then the yearly differences of monthly measurement values look like to be in the range of 0.02 "original data" (what ever this is) and not as being in the range of 0.2 as indicated in fig. 2 in the real climate post. And if I divide by 12 then this gets even worse.

Whereas the corresponding differences for the temperatures could be in the 0.2 range (but what about the factor 1/12?)

Is the green curve in fig. 2 of the realclimate post a diff12 of a temperature or -as the coloring suggests and the mentioning of the Keeling curve- really the Diff12 of the co2 concentrations in fig 1.?

Comment Source:Nathan wrote: >The filter code takes the value for a month and replaces it with a 12-month average. Specifically, it averages over the value for the month being replaced, the values for the preceding 5 months, and for the following 6 months. So if $q= (q_1, q_2,\ldots,q_N)$ is a list of time ordered monthly measurement values then $filter(q_i)= 1/12*\sum_{j=0}^{11} q_{i-5+j}$ Is that correct? And $Diff12(q_i)$ would then be filter $(q_{i+1})-filter(q_i)$ or would it be $filter(q_{i})-filter(q_{i-1})$? But that would then just be the yearly difference in monthly concentrations shifted by e.g. 5 months, i.e. in the first case $q_{i+7}-q_{i-5} = q_{i-5 + 12} - q_{i-5}$ divided by 12 .....If I didnt miscalculated something in my head. So by looking at the co2 curve of concentrations, which looks periodic in year, this difference looks more like being a constant or maybe eventually slightly increasing. So I'd expect a slightly wiggly straight line on a first glance for the diff12 curve of the co2 concentrations. In particular if I look at fig 1 then the yearly differences of monthly measurement values look like to be in the range of 0.02 "original data" (what ever this is) and not as being in the range of 0.2 as indicated in fig. 2 in the real climate post. And if I divide by 12 then this gets even worse. Whereas the corresponding differences for the temperatures could be in the 0.2 range (but what about the factor 1/12?) So I ask again: Is the green curve in fig. 2 of the realclimate post a diff12 of a temperature or -as the coloring suggests and the mentioning of the Keeling curve- really the Diff12 of the co2 concentrations in fig 1.?
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edited March 2013

The filtering description is correct. The differencing is forward differencing.

The iteration over months in the code had puzzled me. My guess, which appears to be correct upon checking, is that they're actually differencing months in successive years. That is, after filtering (smoothing), the differencing is actually between i and i+12, not i and i+1. The green dashed curve in Fig. 2 is the resulting smoothed-and-differenced CO2 curve, whose magnitude is given by the right-hand scale.

Comment Source:The filtering description is correct. The differencing is forward differencing. The iteration over months in the code had puzzled me. My guess, which appears to be correct upon checking, is that they're actually differencing months in successive years. That is, after filtering (smoothing), the differencing is actually between i and i+12, not i and i+1. The green dashed curve in Fig. 2 is the resulting smoothed-and-differenced CO2 curve, whose magnitude is given by the right-hand scale.
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edited March 2013

Nathan wrote:

The differencing is forward differencing.

Forward differencing is this? :

$diffforward(q_i):=q_{i+1}-q_i$

Then the smoothed data are differenced (i.e. differences between successive smooth months are computed.

So you think now this should probably be different?

With

The iteration over months in the code had puzzled me.

you mean that part?:

for (m in 1:12) {´

ii <- is.element(mm, m) ´

#print(c(m,length(ii),sum(ii),length(diff12[m,]),length(diff(x[ii]))))´

diff12[m,] <- diff(x[ii])´


(John wrote that I should use quotation marks for code but I don't no why the quotation marks are here still visible)

I don't know rcode but it looks to me that the differencing is done in that (probably again built-in) function "diff" and the for loop seems is here only for going through the array of monthly values. ??

So it seems to me the big question is now, what is "diff" ? Is it "forward differencing?"

The green dashed curve in Fig. 2 is the resulting smoothed-and-differenced CO2 curve, whose magnitude is given by the right-hand scale.

If I look at the yearly differences in the co2 curve then on the right hand scale they are in the range of 2-4 so this would still not go together with the factor of 1/12.

Comment Source:Nathan <a href="http://forum.azimuthproject.org/discussion/1163/global-warming-in-the-news/?Focus=8793#Comment_8793">wrote:</a> >The differencing is forward differencing. Forward differencing is this? : $diffforward(q_i):=q_{i+1}-q_i$ >Then the smoothed data are differenced (i.e. differences between successive smooth months are computed. So you think now this should probably be different? With >The iteration over months in the code had puzzled me. you mean that part?: for (m in 1:12) {´ ii <- is.element(mm, m) ´ #print(c(m,length(ii),sum(ii),length(diff12[m,]),length(diff(x[ii]))))´ diff12[m,] <- diff(x[ii])´ (John wrote that I should use quotation marks for code but I don't no why the quotation marks are here still visible) I don't know rcode but it looks to me that the differencing is done in that (probably again built-in) function "diff" and the for loop seems is here only for going through the array of monthly values. ?? So it seems to me the big question is now, what is "diff" ? Is it "forward differencing?" The green dashed curve in Fig. 2 is the resulting smoothed-and-differenced CO2 curve, whose magnitude is given by the right-hand scale. If I look at the yearly differences in the co2 curve then on the right hand scale they are in the range of 2-4 so this would still not go together with the factor of 1/12.
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16.

Diff is forward differencing. In R, it's a difference between i and i+1, but they first organize the data into an array by year, so it really ends up being a difference between month i and month i+12, as I mentioned above. I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it's not exactly the same.) It does have the right magnitude.

Comment Source:Diff is forward differencing. In R, it's a difference between i and i+1, but they first organize the data into an array by year, so it really ends up being a difference between month i and month i+12, as I mentioned above. I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it's not exactly the same.) It does have the right magnitude.
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Diff is forward differencing. In R, it’s a difference between i and i+1, but they first organize the data into an array by year, so it really ends up being a difference between month i and month i+12, as I mentioned above. I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.) It does have the right magnitude.

Ah OK I just saw that Wikipedia has even an entry for the term forward difference. Sorry I thought this was again some climatologist-specific term.

So you think that the monthly values are e.g. arranged in the rows of a matrix? Is this because of this line ?:

diff12 <- matrix(rep(NA,n*12),12,n)´

where matrix, rep and NA are again some in-built functions? But then x[ii] looks as if asking for the elements of a tupel not of a matrix.

Is your code in a different computer language? May be I understand that then better.

Comment Source:>Diff is forward differencing. In R, it’s a difference between i and i+1, but they first organize the data into an array by year, so it really ends up being a difference between month i and month i+12, as I mentioned above. I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.) It does have the right magnitude. Ah OK I just saw that Wikipedia has even an entry for the term <a href="http://en.wikipedia.org/wiki/Forward_difference">forward difference</a>. Sorry I thought this was again some climatologist-specific term. So you think that the monthly values are e.g. arranged in the rows of a matrix? Is this because of this line ?: diff12 <- matrix(rep(NA,n*12),12,n)´ where matrix, rep and NA are again some in-built functions? But then x[ii] looks as if asking for the elements of a tupel not of a matrix. Is your code in a different computer language? May be I understand that then better.
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18.

Yes, the matrix statement above is what arranges the months by year, so the differencing will work a year ahead instead of a month ahead. My code is also in R, and so probably will not be easier to understand. In principle, I could unroll all the special operations like filtering into for loops, etc., to make the logic more clear, but I don't really feel like it. It shouldn't be too hard for you to replicate yourself if you know any programming languages; it's just averaging and subtraction.

(For reference, 'matrix' in R makes a matrix where the last 2 arguments are the dimensions and the first argument is a vector of values. 'rep' makes a vector by repeating some number. 'NA' is the "number" being repeated; in this case, it's "not applicable", i.e. missing data. The actual numerical values are assigned later after the matrix is created. It's common to initialize data structures with 'NA' because if you forget to assign them later, your results will always be NA and you'll notice there's a problem.)

Comment Source:Yes, the matrix statement above is what arranges the months by year, so the differencing will work a year ahead instead of a month ahead. My code is also in R, and so probably will not be easier to understand. In principle, I could unroll all the special operations like filtering into for loops, etc., to make the logic more clear, but I don't really feel like it. It shouldn't be too hard for you to replicate yourself if you know any programming languages; it's just averaging and subtraction. (For reference, 'matrix' in R makes a matrix where the last 2 arguments are the dimensions and the first argument is a vector of values. 'rep' makes a vector by repeating some number. 'NA' is the "number" being repeated; in this case, it's "not applicable", i.e. missing data. The actual numerical values are assigned later after the matrix is created. It's common to initialize data structures with 'NA' because if you forget to assign them later, your results will always be NA and you'll notice there's a problem.)
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edited March 2013

Although the paper turns out to be uninteresting in the end, it's popular among climate skeptics, and I believe that thinking about what's wrong with it makes a good exercise in thinking about these issues. So, I do plan to blog about it.

I'm not trying to get anyone to check the DIFF12 calculation, because as far as I can tell the RealClimate people agree with that. As far as I can tell, that's not the problem with this paper. Nonetheless I'm happy that some of you folks are checking this out, because it could be good practice for other things!

So in short if RealClimate which critizes the Humlum et al paper gets the same Diff12(CO2) curve then something (at least for me) unexpected happens and I would like to understand whats going on.

The graphs in the Humlun paper were surprising to me when I first saw them... but the RealClimate post explains why this effect occurs... and then the surprise disappeared. If I were smarter, or more of an expert, I wouldn't have been surprised for as long as I was! But I suspect a lot of nonexperts will be surprised at first - and that's why this can make a good educational blog post. With luck, I can do a better job of explaining to nonexperts what's going on than the RealClimate post did.

Comment Source:Although the paper turns out to be uninteresting in the end, it's popular among climate skeptics, and I believe that thinking about what's wrong with it makes a good exercise in thinking about these issues. So, I do plan to blog about it. I'm not trying to get anyone to check the DIFF12 calculation, because as far as I can tell the RealClimate people _agree_ with that. As far as I can tell, that's not the problem with this paper. Nonetheless I'm happy that some of you folks are checking this out, because it could be good practice for other things! Nad writes > So in short if RealClimate which critizes the Humlum et al paper gets the same Diff12(CO2) curve then something (at least for me) unexpected happens and I would like to understand whats going on. The graphs in the Humlun paper were surprising to me when I first saw them... but the [RealClimate post](http://www.realclimate.org/index.php/archives/2012/09/el-ninos-effect-onco2-causes-confusion/) explains why this effect occurs... and then the surprise disappeared. If I were smarter, or more of an expert, I wouldn't have been surprised for as long as I was! But I suspect a lot of nonexperts will be surprised at first - and that's why this can make a good educational blog post. With luck, I can do a better job of explaining to nonexperts what's going on than the RealClimate post did.
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edited March 2013

John wrote:

I’m not trying to get anyone to check the DIFF12 calculation, because as far as I can tell the RealClimate people agree with that. As far as I can tell, that’s not the problem with this paper.

Actually Nathan seems to agree as well:

I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.)

As said I find this an unexpected result. It goes quite against my mathematical intuition. So Nathan you say that Diff12, as defined in the rcode by the Humlum paper ist given by the following: If $(q_0,q_1,....q_n)$ is a list of monthly measurements and

$filter(q_i)= 1/12*\sum_{j=0}^{11} q_{i-5+j}$

then

$diff12(q_i)= filter(q_{i+12})-filter(q_i)$

Is that correct?

If I look at the code then the temperature values in fig 2 of the realclimate post (red line) seem to come from: http://www.metoffice.gov.uk/hadobs/hadcrut4/data/time_series/hadcrut4_monthly_ns_avg.txt, however the data is not anymore available there.

The dark green line seems to be from ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_gl.txt, the green line from ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt.

Is that correct?

How did you compare the results if the temperature values are not anymore accessible? Was this what you meant with:

(I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.)

What is the Mauna Loa data?

Comment Source:John wrote: >I’m not trying to get anyone to check the DIFF12 calculation, because as far as I can tell the RealClimate people agree with that. As far as I can tell, that’s not the problem with this paper. Actually Nathan seems to agree as well: > I coded this up myself and got an extremely similar result. (I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.) As said I find this an unexpected result. It goes quite against my mathematical intuition. So Nathan you say that Diff12, as defined in the <a href="http://www.realclimate.org/images//hss2012.txt"> rcode by the Humlum paper</a> ist given by the following: If $(q_0,q_1,....q_n)$ is a list of monthly measurements and $filter(q_i)= 1/12*\sum_{j=0}^{11} q_{i-5+j}$ then $diff12(q_i)= filter(q_{i+12})-filter(q_i)$ Is that correct? If I look at the code then the temperature values in fig 2 of the realclimate post (red line) seem to come from: <a href="http://www.metoffice.gov.uk/hadobs/hadcrut4/data/time_series/hadcrut4_monthly_ns_avg.txt">http://www.metoffice.gov.uk/hadobs/hadcrut4/data/time_series/hadcrut4_monthly_ns_avg.txt</a>, however the data is not anymore available there. The dark green line seems to be from <a href="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_gl.txt">ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_gl.txt</a>, the green line from <a href="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt">ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt</a>. Is that correct? How did you compare the results if the temperature values are not anymore accessible? Was this what you meant with: >(I used the Mauna Loa data which I had on hand, which is slightly different from the global data, so it’s not exactly the same.) What is the Mauna Loa data?
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What is the Mauna Loa data?

It's the data set in the context of carbon dioxide changes in the atmosphere (the station is located on a volcano on Hawaii, in a relatively clean and homogeneous environment in the Pacific).

Actually, simply googling "mauna loa data wikipedia" points you to a wiki page about the Mauna Loa Observatory.

Since 1956 Mauna Loa Observatory (MLO) has been monitoring and collecting data relating to atmospheric change, and is known especially for the continuous monitoring of atmospheric carbon dioxide

Comment Source:> What is the Mauna Loa data? It's *the* data set in the context of carbon dioxide changes in the atmosphere (the station is located on a volcano on Hawaii, in a relatively clean and homogeneous environment in the Pacific). Actually, simply googling "mauna loa data wikipedia" points you to a wiki page about the Mauna Loa Observatory. > Since 1956 Mauna Loa Observatory (MLO) has been monitoring and collecting data relating to atmospheric change, and is known especially for the continuous monitoring of atmospheric carbon dioxide
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edited March 2013

OK I could imagine that Nathan took the co2 data from here:

http://co2now.org/Current-CO2/CO2-Now/noaa-mauna-loa-co2-data.html

However since there was the mentioning of a "Keeling curve" it may be that he used this data

For a "global temperature update" the NOOA links to a co2now.org webpage which in the turn links to http://www.realclimate.org/index.php/data-sources/

In order to be able to reproduce the (in my point of view) mathematical oddities mentioned above it is clear that I would need to use the same dataset.

Comment Source:OK I could imagine that Nathan took the co2 data from here: <a href="http://co2now.org/Current-CO2/CO2-Now/noaa-mauna-loa-co2-data.html">http://co2now.org/Current-CO2/CO2-Now/noaa-mauna-loa-co2-data.html</a> However since there was the mentioning of a "Keeling curve" it may be that he used this <a href="http://cdiac.ornl.gov/trends/co2/sio-mlo.html">data</a> For a "global temperature update" the NOOA <a href="http://co2now.org/Know-the-Changing-Climate/Temperature/">links</a> to a <a href="http://co2now.org/Know-the-Changing-Climate/Climate-Science/climate-science-data-sources.html">co2now.org webpage</a> which in the turn links to <a href="http://www.realclimate.org/index.php/data-sources/">http://www.realclimate.org/index.php/data-sources/</a> In order to be able to reproduce the (in my point of view) mathematical oddities mentioned above it is clear that I would need to use the same dataset.
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Your description of the algorithm I implemented is correct. I only did it for the Mauna Loa CO2 data, not temperature, since you seemed to be focused on the green curve. There are some missing values. It could be done with the data sets RealClimate used too. I ran their script and it produced the relevant output without errors, so I'm not sure what's going on with the one missing data set.

Comment Source:nad, Your description of the algorithm I implemented is correct. I only did it for the [Mauna Loa CO2 data](ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt), not temperature, since you seemed to be focused on the green curve. There are some missing values. It could be done with the data sets RealClimate used too. I ran their script and it produced the relevant output without errors, so I'm not sure what's going on with the one missing data set.
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Your description of the algorithm I implemented is correct. I only did it for the Mauna Loa CO2 data, not temperature, since you seemed to be focused on the green curve. There are some missing values. It could be done with the data sets RealClimate used too. I ran their script and it produced the relevant output without errors, so I’m not sure what’s going on with the one missing data set.

OK so diff12 is the annual difference of the annual average. If I take the annual average for the co2 curve I will get an "average curve", i.e. a curve, around which the actual co2 curves oscillates. If I take the annual differences of this curve of averages then similarily as for the annual difference of the values themselves -by looking at the curve- I also expect a rather constant, slightly wiggly line.

Of course one could amplify the wiggles of this line (like by multiplying with a factor), but similarily as in the argumentation above - but I don't see why these wiggles should be in necessarily in (lag)-correlation with the temperature values. So it would be important to get the temperature values. It is strange that the program runs without the temperature data set. There is an if statement in the code, which seems to refer to another location, however the link there doesnt seem to refer to a dataset either: http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt Some hadcrut3 data seems to be here now: http://www.metoffice.gov.uk/hadobs/hadcrut3/data/download.html It's not clear to me though if this is the same data as used in Humlum et al or in the realclimate post.

Comment Source:>Your description of the algorithm I implemented is correct. I only did it for the Mauna Loa CO2 data, not temperature, since you seemed to be focused on the green curve. There are some missing values. It could be done with the data sets RealClimate used too. I ran their script and it produced the relevant output without errors, so I’m not sure what’s going on with the one missing data set. OK so diff12 is the annual difference of the annual average. If I take the annual average for the co2 curve I will get an "average curve", i.e. a curve, around which the actual co2 curves oscillates. If I take the annual differences of this curve of averages then similarily as for the annual difference of the values themselves -by looking at the curve- I also expect a rather constant, slightly wiggly line. Of course one could amplify the wiggles of this line (like by multiplying with a factor), but similarily as in the argumentation above - but I don't see why these wiggles should be in necessarily in (lag)-correlation with the temperature values. So it would be important to get the temperature values. It is strange that the program runs without the temperature data set. There is an if statement in the code, which seems to refer to another location, however the link there doesnt seem to refer to a dataset either: http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt Some hadcrut3 data seems to be here now: <a href="http://www.metoffice.gov.uk/hadobs/hadcrut3/data/download.html">http://www.metoffice.gov.uk/hadobs/hadcrut3/data/download.html</a> It's not clear to me though if this is the same data as used in Humlum et al or in the realclimate post.
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Ok, now their R script is crashing on a file not found.

The best HadCRUT temperature data file to use is here.

The format is a bit strange. Even-numbered lines contain areal coverage (i.e. what fraction of the globe is covered by the data set) and can be ignored here. Odd-numbered lines contain the temperature data: the first column is year, the next twelve columns are the monthly temperature anomalies, and the last column is the annual average temperature anomaly. Missing values are, annoyingly, coded as 0.000 (which could be confused with a true zero temperature anomaly).

Comment Source:Ok, now their R script is crashing on a file not found. The best HadCRUT temperature data file to use is [here](http://www.cru.uea.ac.uk/cru/data/temperature/HadCRUT4-gl.dat). The format is a bit strange. Even-numbered lines contain areal coverage (i.e. what fraction of the globe is covered by the data set) and can be ignored here. Odd-numbered lines contain the temperature data: the first column is year, the next twelve columns are the monthly temperature anomalies, and the last column is the annual average temperature anomaly. Missing values are, annoyingly, coded as 0.000 (which could be confused with a true zero temperature anomaly).
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The best HadCRUT temperature data file to use is here.

In order to be able to compare the results, I would need to use the same data file as they use in Humlum at al and realclimate, even if this may not be necessarily be the best.

In particular it seems the temperature files they used described temperature anomalies, so one would need to know the exact references or averagings which are used for the data.

Your file doesn't say how the values are derived. Moreover I'd prefer that the columns in such a data file are described within the file.

So it seems that since the temperature data vanished, the results of Humlum et al and realclimate can't be reproduced.

Comment Source:>The best HadCRUT temperature data file to use is here. In order to be able to compare the results, I would need to use the same data file as they use in Humlum at al and realclimate, even if this may not be necessarily be the best. In particular it seems the temperature files they used described <a href="http://en.wikipedia.org/wiki/Instrumental_temperature_record#Absolute_temperatures_v._anomalies">temperature anomalies</a>, so one would need to know the exact references or averagings which are used for the data. Your file doesn't say how the values are derived. Moreover I'd prefer that the columns in such a data file are described within the file. So it seems that since the temperature data vanished, the results of Humlum et al and realclimate can't be reproduced.
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Like in that article John Baez had mentioned on G+ about the temperatures they use all sort of wild averaging, estimation and simulation methods, from part 4. Construction of stacks:

We constructed the temperature stack using several different weighting schemes to test the sensitivity of the temperature reconstruction to spatial biases in the dataset. These include an arithmetic mean of the datasets (Standard method), both an area-weighted 5°x5°and 30°x30°lat-lon gridded average, a 10° latitudinal area-weighted mean, and a calculation of 1000 jackknifed stacks that randomly exclude 30% and 50% of the records in each realization

and Fig 8 has a

Simulated global mean temperature for the last 11000 years at the 73 proxy sites (black) from the ECBilt-CLIO transient simulations (81)

where apparently something called accelerated transient boundary conditions was used.

The different methods are reflected in quite different curves (see e.g. Fig S25 page 34), where the differences seem to exceed the temperature ranges as mentioned in the discussions above.

Comment Source:Like in that article <a href="https://plus.google.com/117663015413546257905/posts/YFeTGs3V8E6">John Baez had mentioned on G+</a> about the temperatures they use all sort of wild averaging, estimation and simulation methods, from part 4. Construction of stacks: >We constructed the temperature stack using several different weighting schemes to test the sensitivity of the temperature reconstruction to spatial biases in the dataset. These include an arithmetic mean of the datasets (Standard method), both an area-weighted 5°x5°and 30°x30°lat-lon gridded average, a 10° latitudinal area-weighted mean, and a calculation of 1000 jackknifed stacks that randomly exclude 30% and 50% of the records in each realization and Fig 8 has a >Simulated global mean temperature for the last 11000 years at the 73 proxy sites (black) from the ECBilt-CLIO transient simulations (81) where apparently something called <a href="http://journals.ametsoc.org/doi/abs/10.1175/JCLI4237.1">accelerated transient boundary conditions</a> was used. The different methods are reflected in quite different curves (see e.g. Fig S25 page 34), where the differences seem to exceed the temperature ranges as mentioned in the discussions above.
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edited March 2013

In principle if one used already the Hawaii data for the CO2 measurements, it seems it would make sense to use temperature measurements from the same location. Here is some temperature data from the school of ocean and earth science and technology at the university of Hawai at Maumauna, where most of it seems not publicly accessible though.

Comment Source:In principle if one used already the Hawaii data for the CO2 measurements, it seems it would make sense to use temperature measurements from the same location. Here is some temperature data from the <a href="http://apdrc.soest.hawaii.edu/data/data.php">school of ocean and earth science and technology at the university of Hawai at Maumauna,</a> where most of it seems not publicly accessible though.
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In principle if one used already the Hawaii data for the CO2 measurements, it seems it would make sense to use temperature measurements from the same location.

I'm not an expert on this, but I thought CO2 is well mixed within the atmosphere, and I think surface temperature (or tropospheric temperature at whatever height) is certainly not "well-mixed" across the globe. So I'm not sure if this is really a good thing to do. I think one should compare the well mixed CO2 rises with some kind of average earth temperature.

Comment Source:> In principle if one used already the Hawaii data for the CO2 measurements, it seems it would make sense to use temperature measurements from the same location. I'm not an expert on this, but I thought CO2 is well mixed within the atmosphere, and I think surface temperature (or tropospheric temperature at whatever height) is certainly not "well-mixed" across the globe. So I'm not sure if this is really a good thing to do. I think one should compare the well mixed CO2 rises with some kind of average earth temperature.
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I’m not an expert on this, but I thought CO2 is well mixed within the atmosphere, and I think surface temperature (or tropospheric temperature at whatever height) is certainly not “well-mixed” across the globe.

I am not an expert on this either. I don't know either how well CO2 mixes over the globe. But I could imagine that there are even "vertical" differences, depending on the different airspheres and it seems that there are "horizontal" (i.e. regional) variations, Wikipedia has this animation about mid-tropospheric concentrations.

In particular if you look at the CO2 curve discussed above then there seem to be seasonal oscillations, so alone by this curve one can tell - that the CO2 can't be too well mixed.

Similarily it would be interesting to see how localized the methane concentrations are. The Wikipedia animation is especially interesting in that respect. For example it looks (the globe is turning quite fast) as if there are strong CO2 concentrations over Siberia, this may be partially due to a thawing permafrost which releases methane and which in the turn turns into CO2. However these concentrations could also be due to "winds" from Europe. Like the big concentrations over the Atlantic next to the US east coast seem more likely to be due to the industry emissions of the east coast, then like stemming from gas hydrates.

Comment Source:>I’m not an expert on this, but I thought CO2 is well mixed within the atmosphere, and I think surface temperature (or tropospheric temperature at whatever height) is certainly not “well-mixed” across the globe. I am not an expert on this either. I don't know either how well CO2 mixes over the globe. But I could imagine that there are even "vertical" differences, depending on the different airspheres and it seems that there are "horizontal" (i.e. regional) variations, Wikipedia has this animation about <a href="http://commons.wikimedia.org/w/index.php?title=File%3ACO2_concentrations.ogv">mid-tropospheric concentrations</a>. In particular if you look at the CO2 curve discussed above then there seem to be seasonal oscillations, so alone by this curve one can tell - that the CO2 can't be too well mixed. Similarily it would be interesting to see how localized the methane concentrations are. The Wikipedia animation is especially interesting in that respect. For example it looks (the globe is turning quite fast) as if there are strong CO2 concentrations over Siberia, this may be partially due to a <a href="http://en.wikipedia.org/wiki/Arctic_methane_release#cite_note-11">thawing permafrost</a> which releases methane and which in the turn turns into CO2. However these concentrations could also be due to "winds" from Europe. Like the big concentrations over the Atlantic next to the US east coast seem more likely to be due to the industry emissions of the east coast, then like stemming from <a href="http://en.wikipedia.org/wiki/File:Gas_hydrates_1996.svg">gas hydrates</a>.
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I don't know in which air-sphere (tropo etc.) this flux is taking place: http://en.wikipedia.org/wiki/File:Biosphere_CO2_Flux_08072006.gif". But by this image it looks as if it is more likely that the "winds" play a bigger role in spatial variations of CO2 concentrations than eventual higher local methane concentrations.

Comment Source:I don't know in which air-sphere (tropo etc.) this flux is taking place: <a href="http://en.wikipedia.org/wiki/File:Biosphere_CO2_Flux_08072006.gif">http://en.wikipedia.org/wiki/File:Biosphere_CO2_Flux_08072006.gif"</a>. But by this image it looks as if it is more likely that the "winds" play a bigger role in spatial variations of CO2 concentrations than eventual higher local methane concentrations.
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There are local variations in CO2, e.g. in the amplitude of the seasonal cycle. I would not expect these to have much influence on local temperatures; variations in local temperatures probably have much more to do with teleconnections to large-scale climate patterns like ENSO etc. than they do to the local CO2 forcing.

Comment Source:There are local variations in CO2, e.g. in the amplitude of the seasonal cycle. I would not expect these to have much influence on local temperatures; variations in local temperatures probably have much more to do with teleconnections to large-scale climate patterns like ENSO etc. than they do to the local CO2 forcing.
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edited March 2013

I don’t know in which air-sphere (tropo etc.) this flux is taking place

That figure seems to be the daily variation (0-24) in carbon dioxide due to uptake (blue) or release. I expect it's only the lower part of the boundary layer (which is itself the lower part of the troposphere). Then the shifting pattern in the figure would have nothing to do with winds, it's just because the sun is moving from east to west and plants react to that (perhaps factories too ;-))

[Added: if I remember correctly the well-mixed refers to the stratosphere, where the carbon dioxide influences the radiative forcing]

Comment Source:> I don’t know in which air-sphere (tropo etc.) this flux is taking place That figure seems to be the daily variation (0-24) in carbon dioxide due to uptake (blue) or release. I expect it's only the lower part of the boundary layer (which is itself the lower part of the troposphere). Then the shifting pattern in the figure would have nothing to do with winds, it's just because the sun is moving from east to west and plants react to that (perhaps factories too ;-)) [Added: if I remember correctly the well-mixed refers to the stratosphere, where the carbon dioxide influences the radiative forcing]
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edited March 2013

That figure seems to be the daily variation (0-24) in carbon dioxide due to uptake (blue) or release. I expect it’s only the lower part of the boundary layer (which is itself the lower part of the troposphere). Then the shifting pattern in the figure would have nothing to do with winds, it’s just because the sun is moving from east to west and plants react to that (perhaps factories too ;-))

Yes that gif makes more sense to me now. I think you are right - it was probably carbon dioxide uptake and release on day 08.07.2006 in the lower part of the troposphere. Another indication: although the image is quite flickering it looks also as if the movement goes in another direction then it seems one would expect from atmospheric circulation (do you know wether this "atmospheric circulation pattern holds also for the stratossphere? Or - why is everything well-mixed there?). Despite the fact that the animations showed no "wind" it still appears to me more likely that the high CO2 concentrations in the mid troposphere over Siberia come from atmospheric circulation than from from methane, but I would rather prefer to get more images on these dynamics.

[Added: if I remember correctly the well-mixed refers to the stratosphere, where the carbon dioxide influences the radiative forcing]

It seems the radiative forcing is measured in the tropopause so may be there is also some forcing on the troposphere ? - anyways it would be nice to have similar images/animations for the stratosphere.

I would not expect these to have much influence on local temperatures; variations in local temperatures probably have much more to do with teleconnections to large-scale climate patterns like ENSO etc. than they do to the local CO2 forcing.

Probably - but still it would be interesting to see more images like the above ones, I find. I could imagine that there are at least local differences between north and south hemisphere but then as said above I don't know how the mixing takes place in the stratosphere.

Comment Source:>That figure seems to be the daily variation (0-24) in carbon dioxide due to uptake (blue) or release. I expect it’s only the lower part of the boundary layer (which is itself the lower part of the troposphere). Then the shifting pattern in the figure would have nothing to do with winds, it’s just because the sun is moving from east to west and plants react to that (perhaps factories too ;-)) Yes that gif makes more sense to me now. I think you are right - it was probably carbon dioxide uptake and release on day 08.07.2006 in the lower part of the troposphere. Another indication: although the image is quite flickering it looks also as if the movement goes in another direction then it seems one would expect from <a href="http://en.wikipedia.org/wiki/File:AtmosphCirc2.png">atmospheric circulation</a> (do you know wether this "atmospheric circulation pattern holds also for the stratossphere? Or - why is everything well-mixed there?). Despite the fact that the animations showed no "wind" it still appears to me more likely that the high CO2 concentrations in the mid troposphere over Siberia come from atmospheric circulation than from from methane, but I would rather prefer to get more images on these dynamics. >[Added: if I remember correctly the well-mixed refers to the stratosphere, where the carbon dioxide influences the radiative forcing] It seems the <a href="http://en.wikipedia.org/wiki/Radiative_forcing">radiative forcing is measured in the tropopause </a> so may be there is also some forcing on the troposphere ? - anyways it would be nice to have similar images/animations for the stratosphere. > I would not expect these to have much influence on local temperatures; variations in local temperatures probably have much more to do with teleconnections to large-scale climate patterns like ENSO etc. than they do to the local CO2 forcing. Probably - but still it would be interesting to see more images like the above ones, I find. I could imagine that there are at least local differences between north and south hemisphere but then as said above I don't know how the mixing takes place in the stratosphere.
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edited March 2013

Frederic - with respect to the interpretation of the gif animation I forgot to say: I had erroneously interpreted the non-coloured areas as a lack of data - but of course this is due to the deserts (and oceans).

Comment Source:Frederic - with respect to the interpretation of the gif animation I forgot to say: I had erroneously interpreted the non-coloured areas as a lack of data - but of course this is due to the deserts (and oceans).
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edited March 2013

I was recently told that I should think more like an "entrepreneur", i.e. in particular that I shouldn't spend too much of my time with "unprofitable" ventures like teaching photovoltaics and .....eventually trying to reproduce climate curves.

Let's at least try to speed up this process:

I'd like to compare that methane data (see also this article) with the CO2 data, does anyone know how to get the values without contacting Dr. Dlugokencky ?

Comment Source:I was recently told that I should think more like an "entrepreneur", i.e. in particular that I shouldn't spend too much of my time with "unprofitable" ventures like teaching photovoltaics and .....eventually trying to reproduce climate curves. Let's at least try to speed up this process: I'd like to compare that <a href="http://www.noaanews.noaa.gov/stories2006/images/methane-global-average-05-2006.jpg">methane data</a> (see also this <a href="http://www.esrl.noaa.gov/news/2012/methane.html">article</a>) with the CO2 data, does anyone know how to get the values without contacting Dr. Dlugokencky ?
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edited March 2013

I don't know where the data in that particular graph came from, but this looks like a good place to find monthly averaged methane concentrations as measured at Mauna Loa:

This website has a lot of data.

In particular, here is Ed Dlugokencky's data for monthly averages of methane concentrations from 1983 to 2011.

By the way - it's interesting to see that the concentration of methane in the air depends a lot on the latitude!

(Click for details.)

Comment Source:What do you want to compare about methane and CO2, Nad? I don't know where the data in that particular graph came from, but this looks like a good place to find monthly averaged methane concentrations as measured at Mauna Loa: * [Earth System Research Laboratory Global Monitoring Division - methane in situ monthly averages](http://www.esrl.noaa.gov/gmd/dv/data/index.php?site=mlo&parameter_name=Methane&pageID=2&frequency=Monthly%2BAverages). This website has a lot of data. In particular, [here](ftp://ftp.cmdl.noaa.gov/ccg/ch4/flask/month/ch4_mlo_surface-flask_1_ccgg_month.txt) is Ed Dlugokencky's data for monthly averages of methane concentrations from 1983 to 2011. By the way - it's interesting to see that the concentration of methane in the air depends a lot on the latitude! <a href = "http://www.esrl.noaa.gov/gmd/obop/mlo/programs/esrl/methane/methane.html"><img src = "http://www.esrl.noaa.gov/gmd/obop/mlo/programs/esrl/methane/img/img_global_methane.gif" alt = ""/></a> (Click for details.)
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38.

Yes you found it! Thanks! That saves me from doing expensive (and again: very anti-entrepreneur-spirited (from now on abbreviated simply as VANTEN-spirited or VANTENS) calls to oversea!

In fact I found now also in addition that Dr. Dlugokencky has a ftp server where the Mauna Loa files naming conventions seem to be explained: ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/README_surface_insitu_ch4.html. In that file it is written that:

[parameter][site][project][lab ID number][measurement group]_[optional qualifiers].txt

I was able to learn that the site abbreviation "MLO" seems to mean Mauna Loa, so the file you linked to:

ch4_mlo_surface-insitu_1_ccgg_month.txt

seems to provide -if we assume that this naming convention applies also to this file- indeed a measurement of CH4 at the site Mauna Loa by the measurement strategy "surface insitu" (which I guess is some surface measurement?) by lab nr. 1 by the measurement group ccgg and the data displays the "Computed monthly mean values"

Then in the explanation file one finds the fields explained:

and field 6 is

Dry air mole fraction. Missing values are denoted by -999.99[9].

So I guess one should assume that the numbers in the file you linked to are some mole fractions which are probably the number of molecules of CH4 divided by the number of molecules of dry air found in one fixed volume. Do you see this similarily?

By the way - it’s interesting to see that the concentration of methane in the air depends a lot on the latitude!

click for details ?

it looks as if the graphics doesn't show the southern hemisphere - I could imagine that it is somewhat symmetric with respect to north and south (i.e. that it would ascend again, where the word "global methane" is.) The rise per latitude seems to be at least partially due to circulations. ?

I actually wanted to compare the methane and the CO2 and the temperatures and eventually look if I can find anything which can be remotely be called a time lag but I fear there is not enough data for that. The methane measurements are there only since about 20 years.

Comment Source:Yes you found it! Thanks! That saves me from doing expensive (and again: very anti-entrepreneur-spirited (from now on abbreviated simply as VANTEN-spirited or VANTENS) calls to oversea! In fact I found now also in addition that Dr. Dlugokencky has a ftp server where the Mauna Loa files naming conventions seem to be explained: <a href="ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/README_surface_insitu_ch4.html">ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/README_surface_insitu_ch4.html</a>. In that file it is written that: >[parameter]_[site]_[project]_[lab ID number]_[measurement group]_[optional qualifiers].txt and since I had also found this page: <a href="http://www.esrl.noaa.gov/gmd/dv/iadv/">http://www.esrl.noaa.gov/gmd/dv/iadv/</a> I was able to learn that the site abbreviation "MLO" seems to mean Mauna Loa, so the file you linked to: <a href="ftp://aftp.cmdl.noaa.gov/data/trace_gases/ch4/in-situ/surface/mlo/ch4_mlo_surface-insitu_1_ccgg_month.txt">ch4_mlo_surface-insitu_1_ccgg_month.txt</a> <em>seems to provide</em> -if we assume that this naming convention applies also to this file- indeed a measurement of CH4 at the site Mauna Loa by the measurement strategy "surface insitu" (which I guess is some surface measurement?) by lab nr. 1 by the measurement group ccgg and the data displays the "Computed monthly mean values" Then in the explanation file one finds the fields explained: and field 6 is >Dry air mole fraction. Missing values are denoted by -999.99[9]. So I guess one should assume that the numbers in the file you linked to are some mole fractions which are <em>probably</em> the number of molecules of CH4 divided by the number of molecules of dry air found in one fixed volume. Do you see this similarily? >By the way - it’s interesting to see that the concentration of methane in the air depends a lot on the latitude! click for details ? it looks as if the graphics doesn't show the southern hemisphere - I could imagine that it is somewhat symmetric with respect to north and south (i.e. that it would ascend again, where the word "global methane" is.) The rise per latitude seems to be at least partially due to circulations. ? >What do you want to compare about methane and CO2, Nad? I actually wanted to compare the methane and the CO2 and the temperatures and eventually look if I can find anything which can be remotely be called a time lag but I fear there is not enough data for that. The methane measurements are there only since about 20 years.
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39.

The graph does show both northern and southern latitudes. You might be confused by the 3D projection which appears to cut off at southern latitudes, but if you follow the curves straight down, you see that the cutoff is hovering over or near the 90 S line.

Comment Source:The graph does show both northern and southern latitudes. You might be confused by the 3D projection which appears to cut off at southern latitudes, but if you follow the curves straight down, you see that the cutoff is hovering over or near the 90 S line.
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40.
edited March 2013

So I guess one should assume that the numbers in the file you linked to are some mole fractions which are probably the number of molecules of CH4 divided by the number of molecules of dry air found in one fixed volume.

Yes, that sounds right.

click for details ?

Yeah, click your mouse on the picture to get more details. I try to do that with all important pictures on Azimuth.

it looks as if the graphics doesn’t show the southern hemisphere - I could imagine that it is somewhat symmetric with respect to north and south (i.e. that it would ascend again, where the word “global methane” is.)

No, as Nathan pointed out the graph is very asymmetrical.

There are a lot of bogs in Siberia and Canada, which release methane as the dead vegetable matter rots - and a lot of frozen soil containing organic material (permafrost) in these regions, which rots as the soil warms and melts. But Antarctica is very different. For one thing, instead of a small ocean surrounded by land full of bogs, you've got a small continent covered with a thick layer of ice, surrounded by ocean.

Comment Source:Nad wrote: > So I guess one should assume that the numbers in the file you linked to are some mole fractions which are probably the number of molecules of CH4 divided by the number of molecules of dry air found in one fixed volume. Yes, that sounds right. > click for details ? Yeah, click your mouse on the picture to get more details. I try to do that with all important pictures on Azimuth. > it looks as if the graphics doesn’t show the southern hemisphere - I could imagine that it is somewhat symmetric with respect to north and south (i.e. that it would ascend again, where the word “global methane” is.) No, as Nathan pointed out the graph is very _asymmetrical_. There are a lot of bogs in Siberia and Canada, which release methane as the dead vegetable matter rots - and a lot of frozen soil containing organic material (permafrost) in these regions, which rots as the soil warms and melts. But Antarctica is very different. For one thing, instead of a small ocean surrounded by land full of bogs, you've got a small continent covered with a thick layer of ice, surrounded by ocean. You can read a bit about these issues on Azimuth here: * [[Arctic methane deposits]] * [[Permafrost]] * [[Methane]]
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41.
edited March 2013

but if you follow the curves straight down, you see that the cutoff is hovering over or near the 90 S line.

From this single view I could see it in this way, however I could see it still in the other way, but I now found also this image, which shows that most methane emissions are coming from emissions on land and so your explanation of the 3D projection makes sense if the 3D projection displays methane concentrations near the surface. (....while not really knowing what is meant with computer model...does this mean its no measurement?!) This image displays also that in the stratossphere the situation looks quite different. So it seems circulation patterns are also different in the stratosphere.

and it seems also that in particular not yet so much of the antarctic methane has appeared, at least I haven't seen reports like as they exist for the arctic and it doesnt show up in the 3D projection or the computer model image.

Comment Source:>but if you follow the curves straight down, you see that the cutoff is hovering over or near the 90 S line. From this single view I could see it in this way, however I could see it still in the other way, but I now found also this <a href="http://upload.wikimedia.org/wikipedia/commons/b/b6/AtmosphericMethane.png">image</a>, which shows that most methane emissions are coming from emissions on land and so your explanation of the 3D projection makes sense if the 3D projection displays methane concentrations near the surface. (....while not really knowing what is meant with computer model...does this mean its no measurement?!) This image displays also that in the stratossphere the situation looks quite different. So it seems <a href="http://en.wikipedia.org/wiki/File:AtmosphCirc2.png">circulation patterns</a> are also different in the stratosphere. and it seems also that in particular not yet so much of the <a href="http://news.ucsc.edu/2012/08/antarctic-methane.html">antarctic methane</a> has appeared, at least I haven't seen reports like as they exist for the <a href="neven1.typepad.com/blog/2011/12/arctic-methane-russian-researchers-report/comments/page/2/">arctic</a> and it doesnt show up in the 3D projection or the computer model image.
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42.

Comment Source:@nad: here's a little basic info about the stratospheric circulation: http://www.vets.ucar.edu/vg/StratosphericWinds/index.shtml
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43.

Frederik, thanks for the link. However this visualization seems to be more then 10 years old (date created:2001-12-20) and I am not sure how up-to-date its scientific content is, like they write:

The net result is that particles transported out of the tropics may cover the globe in only two months time.

So if it is correct that methane needs about 10 years to convert a lot of methane into CO2 (see above mentioned article) and if the above mentioned image is right (where most methane looks like centered at the equator) and if this sentence is right (i.e. the methane gets distributed all over the globe within 2 months) then all three informations together look somewhat contradictory.

On the other hand in the video with the simulations it doesnt look as if there is much distribution to the poles, i.e. it doesn't look as if the whole globe is covered by the circulation in the stratossphere, but the quality of the video transmission was not so good over here.

I find it quite remarkable how much money goes into "art" and "ads" and how few money goes into good visualisations of such incredible important (in terms of survival of mankind) scientific information. This visualization center you linked to seems to have been closed. And the climate websites we have sofar visited in this discussion appeared also mostly rather visually untended.

Some reasons are of course that the "markets" are somewhat disconnected, that the corresponding scientific visual language is rather often underdevelopped (even sometimes if in collaboration with artists) and that that scientific imagery would need to compete with perceptionally more direct accessible imagery, like young, naked women on sports cars.

One should probably try to get a superwellknown artist to organize a real sleazy "c-lie-mate porn" funding exhibition to draw more attention to this problem and get some funds for climate science visualisations. This could be e.g. an exhibition like where scientific images look accidentally to some extend like breasts (from here) or other body parts etc., eventually one could combine this with real imagery etc. This could though stir up some disagreement with the scientific community, but if the corresponding artist is doing it right this could eventually even go through as an "art scandal" (it is not so easy to produce an art scandal, they throw meanwhile animals from roofs etc. in order to eventually produce a "scandal") and thus draw in more attention (and eventually funds). However if done badly such an event could be perceived as iNgratiation....

Comment Source:Frederik, thanks for the link. However this visualization seems to be more then 10 years old (date created:2001-12-20) and I am not sure how up-to-date its scientific content is, like they write: >The net result is that particles transported out of the tropics may cover the globe in only two months time. So if it is correct that methane needs about 10 years to convert a lot of methane into CO2 (see above mentioned article) and if the above mentioned <a href="http://upload.wikimedia.org/wikipedia/commons/b/b6/AtmosphericMethane.png">image</a> is right (where most methane looks like centered at the equator) and if this sentence is right (i.e. the methane gets distributed all over the globe within 2 months) then all three informations together look somewhat contradictory. On the other hand in the video with the simulations it doesnt look as if there is much distribution to the poles, i.e. it doesn't look as if the whole globe is covered by the circulation in the stratossphere, but the quality of the video transmission was not so good over here. I find it quite remarkable how much money goes into "art" and "ads" and how few money goes into good visualisations of such incredible important (in terms of survival of mankind) scientific information. This visualization center you linked to seems to have been closed. And the climate websites we have sofar visited in this discussion appeared also mostly rather visually untended. Some reasons are of course that the "markets" are somewhat disconnected, that the corresponding scientific visual language is rather often underdevelopped (even sometimes if in collaboration with artists) and that that scientific imagery would need to compete with perceptionally more direct accessible imagery, like young, naked women on sports cars. One should probably try to get a superwellknown artist to organize a real sleazy "c-lie-mate porn" funding exhibition to draw more attention to this problem and get some funds for climate science visualisations. This could be e.g. an exhibition like where scientific images look accidentally to some extend like <a href="http://en.wikipedia.org/wiki/File:Vol_d%27onde.svg">breasts</a> (from <a href="http://en.wikipedia.org/wiki/Prevailing_winds#Circulation_in_elevated_regions">here</a>) or other body parts etc., eventually one could combine this with real imagery etc. This could though stir up some disagreement with the scientific community, but if the corresponding artist is doing it right this could eventually even go through as an "art scandal" (it is not so easy to produce an art scandal, they throw meanwhile animals from roofs etc. in order to eventually produce a "scandal") and thus draw in more attention (and eventually funds). However if done badly such an event could be perceived as iNgratiation....
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44.
edited March 2013

I wrote:

Then in the explanation file one finds the fields explained

about the explanations for the document: datafile for methane

However if one looks more closely then this doesn't work out. That is it is probably field 5, where the values are given. Moreover field 2 and 3 seem to be year and month, but what is field 4 ? The numbers are not strictly ascending.

I wrote now an email to Dr. Dlugokencky. But I am on the verge of giving up to understand these Hawaian climate infos.

Comment Source:I wrote: >Then in the explanation file one finds the fields explained about the explanations for the document: <a href="ftp://aftp.cmdl.noaa.gov/data/trace_gases/ch4/in-situ/surface/mlo/ch4_mlo_surface-insitu_1_ccgg_month.txt">datafile for methane</a> However if one looks more closely then this doesn't work out. That is it is <em>probably</em> field 5, where the values are given. Moreover field 2 and 3 seem to be year and month, but what is field 4 ? The numbers are not strictly ascending. I wrote now an email to Dr. Dlugokencky. But I am on the verge of giving up to understand these Hawaian climate infos.
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45.

Dr. Dlugokencky wrote me that the information is at the bottom of the document: the right place to look at is at point 7.6 I had falsely looked under hourly averages.

7.6 DATA - MONTHLY AVERAGES

Data files are located in "/ccg/ch4/in-situ/[site]/". There is one monthly mean data file for each site, (e.g., ch4_mlo_surface-insitu_1_ccgg_month.txt). Monthly means are calculated using values extracted at one-day timesteps from a smooth curve (Thoning et al., 1989) fitted to the daily averages.

The data files contain multiple lines of header information followed by one line for each available month.

Fields are defined as follows:

Field 1: [SITE CODE] The three-character sampling location code (see above).

Field 2: [YEAR] The sample collection date and time in UTC. Field 3: [MONTH]

Field 4: [MEAN VALUE] Dry air mole fraction. Missing values are denoted by -999.99[9].

Field 5: [STANDARD DEVIATION] The standard deviation is of the mean of the residuals about the smooth curve.

Field 6: [# OF DAYS] The number of daily averages available.

Field 7: [QC FLAG] A three-character field indicating the results of our data rejection and selection process, described in section 7.4.

Fields in each line are delimited by whitespace.

Apart from this he wrote that the fraction for CH4 is actually nanomole/mole, whereas if I recall correctly the CO2 was measured in micromole/mole. I find this information would be also a useful item in the explanation, even if probably a lot of researchers know which CH4 concentrations to expect. But may be I oversaw this and it was mentioned somewhere.

Comment Source:Dr. Dlugokencky wrote me that the information is at the bottom of the document: the right place to look at is at point 7.6 I had falsely looked under hourly averages. 7.6 DATA - MONTHLY AVERAGES Data files are located in "/ccg/ch4/in-situ/[site]/". There is one monthly mean data file for each site, (e.g., ch4_mlo_surface-insitu_1_ccgg_month.txt). Monthly means are calculated using values extracted at one-day timesteps from a smooth curve (Thoning et al., 1989) fitted to the daily averages. The data files contain multiple lines of header information followed by one line for each available month. Fields are defined as follows: Field 1: [SITE CODE] The three-character sampling location code (see above). Field 2: [YEAR] The sample collection date and time in UTC. Field 3: [MONTH] Field 4: [MEAN VALUE] Dry air mole fraction. Missing values are denoted by -999.99[9]. Field 5: [STANDARD DEVIATION] The standard deviation is of the mean of the residuals about the smooth curve. Field 6: [# OF DAYS] The number of daily averages available. Field 7: [QC FLAG] A three-character field indicating the results of our data rejection and selection process, described in section 7.4. Fields in each line are delimited by whitespace. Apart from this he wrote that the fraction for CH4 is actually nanomole/mole, whereas if I recall correctly the CO2 was measured in micromole/mole. I find this information would be also a useful item in the explanation, even if probably a lot of researchers know which CH4 concentrations to expect. But may be I oversaw this and it was mentioned somewhere.
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46.
edited March 2013

Thanks for getting that information from Dlugokencky, Nad!

I agree that it would be great to present this data in a nice visual form with good explanations! In some ways this is easier than doing really good data analysis... but scientists don't put much work into visual presentations. I don't know how to produce an arts scandal; I don't even think I want to. But presenting information in a way that's a bit easier to understand is something that I, or better we, could do. Then maybe some artists and advertisers and experts on visual media could look at what we did, and make something even more vivid.

Comment Source:Thanks for getting that information from Dlugokencky, Nad! I agree that it would be great to present this data in a nice visual form with good explanations! In some ways this is easier than doing really good data analysis... but scientists don't put much work into visual presentations. I don't know how to produce an arts scandal; I don't even think I want to. But presenting information in a way that's a bit easier to understand is something that I, or better _we_, could do. Then maybe some artists and advertisers and experts on visual media could look at what we did, and make something even more vivid.
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47.

The question about how methane could be so inhomogeneously distributed in the atmosphere if its mean lifetime is 10 years is an interesting one!

Comment Source:The question about how methane could be so inhomogeneously distributed in the atmosphere if its mean lifetime is 10 years is an interesting one!
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48.

I have copied some of the information from this thread to Methane. In general, if we uncover any interesting information in the discussions here, we should put it in the Azimuth Wiki so it doesn't get lost later.

Comment Source:I have copied some of the information from this thread to [[Methane]]. In general, if we uncover any interesting information in the discussions here, we should put it in the Azimuth Wiki so it doesn't get lost later.
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49.
edited March 2013

There is now some more and eventually new (at least I havent seen this position yet) evidence on methane. From the Azimuth project page:

The diff12 of methane values can be compared in an interactive diagram at our personal website with the diff12 values of CO2 and Temperature anomalies from HADCRUT. The findings of Humlum et al. are recovered. Moreover it looks to me that methane diff12 values precede temperature diff12 values (and thus diff12 CO2 values, which could be due to the decay of methane into CO2). Of course it is scientifically rather shaky to infer causal relations from such findings and thus it would be way too unsolid to infer from the above that methane might be a bigger driving force of global warming than CO2 - however it is suggestive to look for further evidence into that direction.

by the way it took me quite an amount of time to do this interactive chart and Tim had to help me as well. I did this because I think it is an incredible important issue to look at and it seems somehow that things have been interpreted differently in the main stream.

Comment Source:There is now some more and eventually new (at least I havent seen this position yet) evidence on methane. From the <a href="http://www.azimuthproject.org/azimuth/show/Does+global+warming+lag+or+lead+a+rise+in+greenhouse+gas+concentration%3F">Azimuth project page:</a> >The diff12 of methane values can be compared in an <a href="http://www.daytar.de/art/co2ch4TempViz/index.html">interactive diagram at our personal website</a> with the diff12 values of CO2 and Temperature anomalies from HADCRUT. The findings of Humlum et al. are recovered. Moreover it looks to me that methane diff12 values _precede_ temperature diff12 values (and thus diff12 CO2 values, which could be due to the decay of methane into CO2). Of course it is scientifically rather shaky to infer causal relations from such findings and thus it would be way too unsolid to infer from the above that methane might be a bigger driving force of global warming than CO2 - however it is suggestive to look for further evidence into that direction. by the way it took me <em>quite</em> an amount of time to do this interactive chart and Tim had to help me as well. I did this because I think it is an incredible important issue to look at and it seems somehow that things have been interpreted differently in the main stream.
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50.
edited March 2013

So if it is correct that methane needs about 10 years to convert a lot of methane into CO2 (see above mentioned article) and if the above mentioned image is right (where most methane looks like centered at the equator) and if this sentence is right (i.e. the methane gets distributed all over the globe within 2 months) then all three informations together look somewhat contradictory.

Perhaps the explanation could be that the image is for the troposphere whereas the 'rapid' mixing is for the stratosphere. This is just a guess.

One should probably try to get a superwellknown artist to organize

About the art, I think it would perhaps be cool for artists to incorporate scientific themes in their work, but rather like this then the other way round.

With respect to

that that scientific imagery would need to compete with perceptionally more direct accessible imagery, like young, naked women on sports cars

I think that there is simply a different public, and that such efforts are in vain. People interested in the latter will not become interested in science just because it would be accompanied by women. They may be interested in the women but then not more than that. (And this holds as well for women as for men)

Comment Source:> So if it is correct that methane needs about 10 years to convert a lot of methane into CO2 (see above mentioned article) and if the above mentioned image is right (where most methane looks like centered at the equator) and if this sentence is right (i.e. the methane gets distributed all over the globe within 2 months) then all three informations together look somewhat contradictory. Perhaps the explanation could be that the image is for the troposphere whereas the 'rapid' mixing is for the stratosphere. This is just a guess. > One should probably try to get a superwellknown artist to organize About the art, I think it would perhaps be cool for artists to incorporate scientific themes in their work, but rather like this then the other way round. With respect to > that that scientific imagery would need to compete with perceptionally more direct accessible imagery, like young, naked women on sports cars I think that there is simply a different public, and that such efforts are in vain. People interested in the latter will not become interested in science just because it would be accompanied by women. They may be interested in the women but then not more than that. (And this holds as well for women as for men)