It's getting very warm again. January was warmer than any month before October 2015 in the MOyhu NCEP/NCAR reanalysis index. February was warmer again, and is warmer than Oct/Nov 2015, and behind only Dec-April in the 2015/6 El Nino. And it shows no downturn at end month.
Karsten also had a rise of 0.1°C from GFS/CFSR. UAH V6 is up by 0.05°C. And as I noted in the previous post, Antarctic sea ice reached a record low level a few days ago.
AI Lions and Renewable Straw
3 hours ago
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These data are very interesting to me. Looking at the monthly data, from Jan 2014 to July 2015, the NCEP/NCAR temperatures are basically in the range of 0.1 to 0.3. Then they zoom up to the El Nino peak, and back down ... but not quite as far back down. After the peak they are in the range 0.35 to 0.5, except this latest one is even warmer.
ReplyDeleteIt looks like the EN peak is associated with a step-change in temperature; after the peak it is about 0.23 C higher than before the peak.
There is a similar pattern in GISTEMP, though not quite as dramatically clear.
I feel vaguely like there was a similar pattern around the 1998 El Nino, though in that case the trough immediately after the peak was deeper -- but there was a similar sort of step-change in temperature from before to after the peak.
Maybe some of the warm water from the Nino region travels to other parts of the ocean and continues to warm the atmosphere. Just a thought. If so, there should also be a step up in global SST's.
DeleteOr maybe the heat from a strong El Niño creates warming feedbacks (like more water vapor, less sea ice).
DeleteCliff,
ReplyDeleteThats called the residual warming of El-Nino. Its always to keep in mind, that el-nino is a weaking of trade winds and trade winds cause divergence in the inner tropics to the midlatitudes. If trade winds weakens, so the energy begins to store in the inner tropics (thats why the very most impact of el-nino is in the time after Dezember) then later, the el nino beginns to weaken and divergence begin to start again and push the stored energy out of the tropics
Actually, the Pacific Equatorial waters (0-300m) have not released heat since May 2016, but have built up a considerable amount of heat since then. The Nino heat peaked in Oct 2015.
DeleteHere a chart from CPC:
http://www.cpc.ncep.noaa.gov/products/intraseasonal/tlon_heat.gif
As a graph via Knmi climate explorer 1996- Feb 2017:
http://postmyimage.com/img2/209_image.png
The drop in eqatorial heat was much larger in 1997-1998, and it took much longer time to restore the heat.
Hence, I believe that the recent el Nino and post el Nino warming is more driven by factors outside the tropics, compared to 1997-1998.
Olaf - The Pacific tropical OHC plot is very interesting! It paints a consistent pattern with the relatively muted response to the 16/17 nino in UAH6 and other satellite products compared to 97/98. My take is that the relaxation in trade winds in the 2011/12 timeframe, after a decade of relatively strong trades, allowed global temperatures to spring back to the trendline. Now that the PDO has switched, positive enso and weak Pacific trades are expected along with a prolonged period above the global temperature trendline.
DeleteChubbs
I agree. The recent La Niña was, in a way, choked off... stunted on all sides... fenced in by warm waters that did not yield. If you look at current SSTA, it already looks like a developed El Niño:
Deletehttp://www.ospo.noaa.gov/data/sst/anomaly/2017/anomnight.3.2.2017.gif
The PDO, on the other hand, appears anyway, to be weakening. It will be interesting to see it strengthens in the NH summer. If it does, no wind, the 2016 reign as warmest year is in trouble.
To clarify my post above, the recent surge in global warming is not due solely to the strength of the 15/16 nino, which was weaker than 97/98, instead the warming has been enhanced by a reversal of the factors that led to the hiatus period.
DeleteChubbs