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Saturday, October 12, 2013

Quick Note on Getting Rid of Climate Oscillations

Weather is chaotic Climate is less chaotic.  Trying to separate to two can be a PITA.  So I have focused on the tropics which have the majority of the energy and by extending the tropics to 30S-30N the majority of the surface area.  So to justify this simplification to some of the more stubborn doubters here is a little illustration.

This the ERSSTv3b combined land and ocean data in 30 degree latitude bands using the 1900-1999 baseline.  Since I am looking for a gross impact not a regional contribution I average the latitude bans by hemisphere.

With no areal adjustment which I can get away with by using the combined land and ocean data you can see that this simple averaging removes a lot of the internal variability.  The 30-0 band is less sensitive to various forcings providing what I believe is a good "global" reference.  You can see that I have added the Oppo 2009 Indo-Pacific warm pool reconstruction.

Expanding the range to 1700ad, the Oppo 2009 provides a rough slope for the tropics and likely global recovery slope from the Little Ice Age.  There is some indication of additional "forcing" which if 280 ppm CO2 is "normal" then that could be used as a second reference.

This include the CO2 response of 1.0 C per doubling.  This "method" or simplification doesn't prove anything but it is a reference that I will likely use more often so this just explains what I am doing and why hopefully.  I see no reason to waste time on internal oscillations that tend to cancel each other.

 In any case, allowing for the secular trend from the Little Ice Age produces this fit with no feedback CO2 forcing.  I see no reason to remove ENSO etc. that are truly "Global" because they make good reference points, like 1940-1945 for example :)

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