by Bob Tisdale

THE EAST PACIFIC VERSUS THE REST OF THE WORLD

This month I’m going to start the update with the two graphs that represent the East Pacific and the Rest-Of-The-World Sea Surface Temperature (SST) anomalies. These datasets were discussed in the post Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World.Both datasets have been adjusted for the impacts of volcanic aerosols, and both are smoothed with 13-month running-average filters to reduce the seasonal noise. The global oceans were divided into these two subsets to illustrate two facts. First, the linear trend of the volcano-adjusted East Pacific (90S-90N, 180-80W) SST anomalies since the start of the Reynolds OI.v2 dataset is basically flat. The East Pacific linear trend varies with each monthly update, so with ENSO-related SST anomalies varying from La Niña toward zero, that trend will also rise slightly each month. But it won’t rise significantly up through the next El Niño.

(3) Volcano-Adjusted East Pacific (90S-90N, 180-80W)

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And second, the volcano-adjusted SST anomalies for the Rest of the World (90S-90N, 80W-180) rise in very clear steps, in response to the significant 1986/87/88 and 1997/98 El Niño/La Niña events. It also appears as though the SST anomalies of this dataset are making another shift in response to the most recent ENSO event.

(4) Volcano-Adjusted Rest of the World (90S-90N, 80W-180)

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The “July 2009 to Present” average varies with each update. As noted in the linked post, it will be interesting to see where that SST anomaly average settles out, if it does, before the next significant El Niño drives them higher.

The SST anomalies of the East Pacific Ocean, or approximately 33% of the surface area of the global oceans, have risen very little since 1982 based on the linear trend. And between upward shifts, the SST anomalies for the rest of the world (67% of the global ocean surface area) remain relatively flat. Anthropogenic forcings are said to be responsible for most of the rise in global surface temperatures over this period, but the SST anomaly graphs of those two areas prompt a two-part question: Since 1982, what anthropogenic global warming processes would overlook the sea surface temperatures of 33% of the global oceans and have an impact on the other 67% but only in response to the significant El Niño events of 1986/87/88, 1997/98 and 2009/10?

Back to the monthly update.

MONTHLY SST ANOMALY MAP

The following is a Global map of Reynolds OI.v2 SST anomalies for May 2011 downloaded from the NOMADS website. The contour levels are set at 0.5 deg C, and white is set at zero.

May 2011 SST Anomalies Map (Global SST Anomaly = +0.132 deg C)

MONTHLY OVERVIEW

Monthly NINO3.4 SST anomalies are within ENSO-neutral conditions and continuing their rise toward zero. The Monthly NINO3.4 SST Anomaly is -0.34 deg C.

The SST anomalies in Northern Hemisphere rose (about +0.07 deg C) this month. That rise was countered by a drop (approximately -0.04 deg C) in Southern Hemisphere SST anomalies. Global SST anomalies rose slightly (+0.009 deg C). The Global SST anomalies are presently at +0.132 deg C.

(1) Global

Monthly Change = +0.009 deg C

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(2) NINO3.4 SST Anomaly

Monthly Change = +0.322 deg C

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EAST INDIAN-WEST PACIFIC

The SST anomalies in the East Indian and West Pacific rose slightly this month.

I’ve added this dataset in an attempt to draw attention to what appears to be the upward steps in response to significant El Niño events that are followed by La Niña events.

(5) East Indian-West Pacific (60S-65N, 80E-180)

Monthly Change = +0.038 deg C

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Further information on the upward “step changes” that result from strong El Niño 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

The animations included in the post La Niña Is Not The Opposite Of El Niño – The Videosfurther help explain the reasons why East Indian and West Pacific SST anomalies can rise in response to both El Niño and La Niña events.

NOTE ABOUT THE DATA

The MONTHLY graphs illustrate raw monthly OI.v2 SST anomaly data from December 1981 to May 2011, as it is presented by the NOAA NOMADS website linked at the end of the post.

MONTHLY INDIVIDUAL OCEAN AND HEMISPHERIC SST UPDATES

(6) Northern Hemisphere

Monthly Change = +0.067 deg C

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(7) Southern Hemisphere

Monthly Change = -0.037 deg C

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(8) North Atlantic (0 to 75N, 78W to 10E)

Monthly Change = +0.050 deg C

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(9) South Atlantic (0 to 60S, 70W to 20E)

Monthly Change = -0.150 deg C

Note: I discussed the upward shift in the South Atlantic SST anomalies in the post The 2009/10 Warming Of The South Atlantic. It does not appear as though the South Atlantic will return to the level it was at before that surge, and where it had been since the late 1980s. That is, it appears to have made an upward step and continues to rise. Why? Dunno—yet.

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(10) North Pacific (0 to 65N, 100E to 90W)

Monthly Change = +0.083 Deg C

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(11) South Pacific (0 to 60S, 120E to 70W)

Monthly Change = +0.042 deg C

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(12) Indian Ocean (60S to 30N, 20E to 120E)

Monthly Change = -0.006 deg C

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(13) Arctic Ocean (65N to 90N)

Monthly Change = +0.047 deg C

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(14) Southern Ocean (90S-60S)

Monthly Change = -0.071 deg C

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WEEKLY SST ANOMALIES

WEEKLY NINO3.4 SST ANOMALIES

The weekly NINO3.4 Sea Surface Temperature (SST) Anomalies have risen well above the threshold of a La Niña, and are quickly approaching zero. The NINO3.4 SST anomaly based on the week centered on June 1, 2011 is -0.207 deg C.

(15) Weekly NINO3.4 SST Anomalies

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The weekly global SST anomalies are at +0.105 deg C.

(16) Weekly Global

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SOURCE

The Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).

http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh

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