“Hot” on the heels (ahem) of the March UAH global temperature anomaly, we have the likely primary driver of that number, a persistent El Nino in the Pacific. WUWT contributor Bob (you want graphs with that?) Tisdale explains. – Anthony
Guest Post by Bob Tisdale
MONTHLY SST ANOMALY MAP
The map of Global OI.v2 SST anomalies for March 2010 downloaded from the NOMADS website is shown below. Note the pattern of warm SST anomalies over the Southern part of the North Atlantic and cool SST anomalies in the Gulf of Mexico. If the pattern persisted through the summer months (big IF), how would it impact the hurricane season?
March 2010 SST Anomalies Map (Global SST Anomaly = +0.301 deg C)
Note: I was advised via email that the NOAA corrected the February OI.v2 SST data. It represents an upward change of only ~0.005 deg C globally, but since it was a correction in areas with sea ice, I decided to check those as well. The February Arctic Ocean SST anomalies rose ~0.02 deg C and the Southern Ocean SST anomalies ~0.03 deg C with the corrections.
There was a minor rise (0.012 deg C) this month in Global SST anomalies. SST Anomalies in both the Southern and Northern Hemispheres rose approximately the same amount. El Nino conditions remain in the central tropical Pacific (Monthly NINO3.4 SST Anomaly = +1.14 deg C and Weekly NINO3.4 SST Anomaly = +0.97 deg C), but SST anomalies there are dropping. Monthly NINO3.4 SST anomalies dropped 0.10 in March. The North Atlantic, Indian Ocean and the East Indian-West Pacific Ocean datasets all show significant rises this month. They are partly offset by the drops in the Pacific and South Atlantic.
Monthly Change = +0.012 deg C
NINO3.4 SST Anomaly
Monthly Change = -0.104 deg C
EAST INDIAN-WEST PACIFIC
The SST anomalies in the East Indian and West Pacific continue their lagged rise in response to the El Nino. Will they also rise, noticeably, in response to the La Nina as they have in the past?
I’ve added this dataset in an attempt to draw attention to the upward step response. Using the 1986/87/88 and 1997/98 El Nino events as references, East Indian-West Pacific SST Anomalies peak about 7 to 9 months after the peak of the NINO3.4 SST anomalies, so we shouldn’t expect any visible sign of a step change for almost 18 to 24 months. We’ll just have to watch and see.
East Indian-West Pacific (60S-65N, 80E-180)
Monthly Change = +0.084 deg C
Further information on the upward “step changes” that result from strong El Nino events, refer to my posts from a year ago Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1 and Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2
And for the discussions of the processes that cause the rise, refer to More Detail On The Multiyear Aftereffects Of ENSO – Part 2 – La Nina Events Recharge The Heat Released By El Nino Events AND…During Major Traditional ENSO Events, Warm Water Is Redistributed Via Ocean Currents -AND- More Detail On The Multiyear Aftereffects Of ENSO – Part 3 – East Indian & West Pacific Oceans Can Warm In Response To Both El Nino & La Nina Events
NOTE ABOUT THE DATA
The MONTHLY graphs illustrate raw monthly OI.v2 SST anomaly data from November 1981 to March 2009.
MONTHLY INDIVIDUAL OCEAN AND HEMISPHERIC SST UPDATES
Monthly Change = +0.013 deg C
Monthly Change = +0.011 deg C
North Atlantic (0 to 75N, 78W to 10E)
Monthly Change = +0.120 deg C
South Atlantic (0 to 60S, 70W to 20E)
Monthly Change = -0.007 deg C
Note: The 2009 upward shift in South Atlantic SST anomalies is becoming very obvious. I’ll have to work up a post about it. I have yet to see a paper that explains it.
North Pacific (0 to 65N, 100 to 270E, where 270E=90W)
Monthly Change = -0.058 Deg C
South Pacific (0 to 60S, 145 to 290E, where 290E=70W)
Monthly Change = -0.033 deg C
Indian Ocean (30N to 60S, 20 to 145E)
Monthly Change = +0.082 deg C
Arctic Ocean (65 to 90N)
Monthly Change = -0.092 deg C
Southern Ocean (60 to 90S)
Monthly Change = +0.120 deg C
WEEKLY NINO3.4 SST ANOMALIES
The weekly NINO3.4 SST anomaly data illustrate OI.v2 data centered on Wednesdays. The latest weekly NINO3.4 SST anomalies are +0.97 deg C. They’re working their way down.
Weekly NINO3.4 (5S-5N, 170W-120W)
The Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).