Wednesday, April 29, 2015

Movies for global CO2 and CH4

These have been around for a while, but I didn't know about them. Starting about 2007, NOAA has had a Carbon Tracker program. It is a kind of reanalysis program that assimilates mainly ground-based data to form a global model. I was reminded of it when I saw this recent conference paper which compared results with the two pre-OCO satellite data sets AIRS and GOSAT.

And it has movies. Lots of them, from about 2000 to 2010, of both atmospheric CO2 and CH4. When the first OCO movies came out late 2014, there was some murmuring that these would upset the CO2 applecart. Those were of course for just one part of the seasonal cycle, and some features they showed, such as an Amazon Basin hotspot, could seem unexpected. But they are there on the earlier NOAA movies, although those have much more NH CO2 at that time of year.

So are they reliable? Well, according to the linked paper, somewhat. They have resolution limitations, and do overstate the NH at times, but a lot seems reasonable. I'll add the link to the directory to the portals page, but of course, Moyhu has to have a gadget. This will allow you to choose by gas (CO2, CH4), year, and projection - global (Hammer), or orthographic (US-centered). Some movies are Quicktime (.mov), so you might need to have a plug-in. Others are animated GIF. One year/season is about 10 Mb, so may take a while to download.

Update - I find that the CO2 movies, which are in quicktime format, don't work for me in Chrome, and it seems that there is some issue there with plugins. If you don't get an immediate response asking to allow quicktime to operate, then probably nothing will happen. The CH4 movies are in animated gif, which should be no problem.

You should first choose which gas and which projection, with the radio buttons. "Hammer" is global; "ortho" shows a sphere world centered on US. Then choose a time period. If you hover the mouse over the red strip, periods will appear in faint text below the Show button. Most recent (2010) is at the top. CH4 movies are in 3-month parts, so you'll see the season appended (djf=Dec-Feb, etc). Move up or down to get the period you want, then click, and it will appear in a box below.

Then you can click Show, being aware that this will download a file of 10Mb or so. CO2 will come up as a Quicktime movie, CH4 as an animated GIF.

I think the CO2 movies are very timely. I think it is worth reviewing them as background to the OCO-2 results which will trickle out (very slowly so far).


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