March 2012 Sea Surface Temperature (SST) Anomaly Update – A New Look

Guest post by Bob Tisdale

THE ADDITION OF CMIP3 (IPCC AR4) HINDCASTS/PROJECTIONS TO GRAPHS

I’ve added a new feature to the graphs of the monthly sea surface temperature updates on a trial basis, and it is the multi-model mean of the CMIP3 hindcasts/projections for sea surface temperatures, presenting them in comparisons to the observed data. The observed and modeled linear trends are also shown. This is done for the global, hemispheric and ocean basin sea surface temperature anomalies. As you will recall, CMIP3 is the climate model archive used by the IPCC for its 4^thAssessment Report (AR4). I haven’t decided whether to include the model simulation data and trends in each monthly update or to include them only on a quarterly basis; that is, for the monthly updates in March, June, September, and December. I’m leaning toward providing them on a quarterly basis, not only because they’re a lot of extra work, but the model data also detracts from the data update itself. On the other hand, it would likely be good to provide the monthly reminder of just how poorly the models simulate global and regional sea surface temperatures.

The multi-model mean and linear trends of the CMIP3 model simulation data definitely make the graphs busier. Refer to the Global sea surface temperature anomaly graph. We added the smoothed data (13-month running-average filter) on a trial basis a few months ago, and readers requested that we keep the smoothed data. On some occasions, the trend lines may obscure the most recent changes in the dataset. Let me know whether we should include the additional climate model data in each monthly update or if you would prefer it on a quarterly basis.

(1) Global Sea Surface Temperature Anomalies

Monthly Change = -0.016 deg C

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NOTES ABOUT THE MODEL-OBSERVATION COMPARISONS

The model-observations comparisons serve as updates to two of my favorite posts: Satellite-Era Sea Surface Temperature Versus IPCC Hindcast/Projections Part 1 and Part 2. Refer to those posts for the discussions of the monumental differences between the models and observations. They are also presented in my book, in Section 8.

A couple of notes: The multi-model mean data are not expected to present the year-to-year variations in sea surface temperature associated with the El Niño-Southern Oscillation (ENSO). Some of the models simulate ENSO; others don’t. The models that do attempt to simulate ENSO do a poor job of it. (This is documented in numerous peer-reviewed papers.) Each model produces ENSO events on its own schedule; that is, the modeled ENSO events do not reproduce the observed frequency, duration, and magnitude of El Niño and La Niña events. Since the multi-model mean presents the average of all of those out-of-synch ENSO signals, they are smoothed out. For this reason, we are only concerned with the disparity in the modeled and observed trends.

And as shown above, the difference between the linear trends on a global basis is quite large. The model simulations hindcast/project a global sea surface temperature anomaly warming rate that is about 80% higher than the observed rate. Depending on the subset, the models perform better and worse. For example, the model-simulated rate of warming for Northern Hemisphere sea surface temperature anomalies is only about 24% higher than observed, while in the Southern Hemisphere, the models say the sea surface temperatures should be warming at a rate that is more than 2.5 times faster than the observed rate.

Part 1 and Part 2 of Satellite-Era Sea Surface Temperature Versus IPCC Hindcast/Projections and my bookalso illustrate the differences in observed and modeled trends on a zonal mean basis. See example below for the global oceans, which shows the trends from November 1981 to February 2011. In my view, this is the greatest failing of the models. For the last 30 years, the models show the global oceans warming faster in the tropics than at mid latitudes and faster at mid latitudes than at the poles. And it’s very obvious that the global oceans have not warmed in that fashion over the past 30+ years. The warming of the global oceans since November 1981 is actually greatest toward the high latitudes of the Northern Hemisphere, while the oceans south of about 50S have cooled. Note also that there has been comparatively little warming at the equator.

(16) Global Zonal Mean Model-Data Comparison – Trends

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Those zonal mean graphs will not be updated as part of these posts.

Keep in mind, the global oceans represent about 70% of the surface area of the globe, and the climate models show no skill at being able to simulate the warming of their surface. As discussed under the heading of THE EAST PACIFIC VERSUS THE REST OF THE WORLD in this post, global sea surface temperatures have warmed over the past 30+ years in response to ENSO events, not anthropogenic greenhouse gases. This was presented and discussed in detail in my book titled If the IPCC was Selling Manmade Global Warming as a Product, Would the FTC Stop their Deceptive Ads?and in a good number of posts at my blog.

When CMIP5-based sea surface temperature data is available through the KNMI Climate Explorer, I will provide a post about it, to serve as a preview of the IPCC’s upcoming 5^thAssessment Report.

Last, the differences between models and observations are not discussed throughout the rest of the post. The remainder is the normal monthly sea surface temperature update. Feel free, however, to comment on the disparity between the models and the observations.

MONTHLY SST ANOMALY MAP

The following is a Global map of Reynolds OI.v2 Sea Surface Temperature (SST) anomalies for March 2012 downloaded from the NOMADS website. The contour level is set at 0.5 deg C, and white is set at zero.

March 2012 Sea Surface Temperature (SST) Anomalies Map

(Global SST Anomaly = +0.106 deg C)

MONTHLY OVERVIEW

The Monthly NINO3.4 SST Anomaly continued their climb toward zero in March 2012, rising about +0.196 deg C, to -0.467 deg C, which is just above the -0.5 deg C threshold of a La Niña event.

(2) NINO3.4 Sea Surface Temperature Anomalies

(5S-5N, 170W-120W)

Monthly Change = +0.196 deg C

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On the other hand, Global Sea Surface Temperature anomalies, as shown at the opening of the post, cooled slightly, approximately -0.016 deg C. Both hemispheres cooled this month, with the greater drop taking place in the Northern Hemisphere. The monthly Global Sea Surface Temperature anomalies are presently at +0.106 deg C.

THE EAST PACIFIC VERSUS THE REST OF THE WORLD

Note:  I have not included the model data for these two subsets. They would detract from the discussions of them.

The East Pacific and the Rest-Of-The-World (Atlantic-Indian-West Pacific) datasets were first 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. 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) Sea Surface Temperature anomalies since the start of the Reynolds OI.v2 dataset is basically flat. The East Pacific linear trend varies with each monthly update. But it won’t vary significantly between El Niño and La Niña events.

(3) Volcano-Adjusted East Pacific Sea Surface Temperature (SST) Anomalies

(90S-90N, 180-80W)

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And second, the volcano-adjusted Sea Surface Temperature anomalies for the Rest of the World (90S-90N, 80W-180) rise in very clear steps, and those rises are clearly in response to the significant 1986/87/88 and 1997/98 El Niño/La Niña events. It also appears as though the Sea Surface Temperature anomalies of this dataset are making another upward shift in response to the more recent 2009/10 ENSO event. For those who are interested in the actual trends of the Sea Surface Temperature anomalies between the 1986/87/88 and 1997/98 El Niño events and between the 1997/98 and 2009/10 El Niño events refer to Figure 4 in Does The Sea Surface Temperature Record Support The Hypothesis Of Anthropogenic Global Warming? I further described (at an introductory level) the ENSO-related processes that cause these upward steps in the post ENSO Indices Do Not Represent The Process Of ENSO Or Its Impact On Global Temperature.

I also went into greater detail to describe the ENSO-related processes that cause those upward shifts in Section 6 of my book. Section 6 takes the reader from a very basic description of the El Niño-Southern Oscillation (ENSO) through to how certain parts of the global oceans warm in response to El Niño AND La Niña events. Refer to the Table of Contents included in the .pdf file here.

(4) Volcano-Adjusted Sea Surface Temperature Anomalies For The Rest of the World

(90S-90N, 80W-180)

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The periods used for the average Rest-Of-The-World Sea Surface Temperature anomalies between the significant El Niño events of 1982/83, 1986/87/88, 1997/98, and 2009/10 are determined as follows. Using the NOAA Oceanic Nino Index(ONI) for the official months of those El Niño events, I shifted (lagged) those El Niño periods by six months to accommodate the lag between NINO3.4 SST anomalies and the response of the Rest-Of-The-World Sea Surface Temperature anomalies, then deleted the Rest-Of-The-World data that corresponds to those significant El Niño events. I then averaged the Rest-Of-The-World SST anomalies between those El Niño-related gaps.

The “Nov 2010 to Present” average varies with each update. As noted in the post Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World, it will be interesting to see where that Sea Surface Temperature anomaly average settles out, if it does, before the next significant El Niño drives them higher.

Of course, something could shift. Will the upward ratcheting continue when the Atlantic Multidecadal Oscillation (AMO) decides to turn around and start its decline? The upward steps would not continue in the North Atlantic, but would the AMO impact the upward steps in other portions of the globe? For more information about the Atlantic Multidecadal Oscillation, refer to the post An Introduction To ENSO, AMO, and PDO — Part 2.

The Sea Surface Temperature anomalies of the East Pacific Ocean, or approximately 33% of the surface area of the global oceans, have decreased slightly since 1982 based on the linear trend. And between upward shifts, the Sea Surface Temperature 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 Sea Surface Temperature 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 during the months of the significant El Niño events of 1986/87/88, 1997/98 and 2009/10?

NOTE ABOUT THE DATA

The MONTHLY graphs illustrate raw monthly OI.v2 SEA SURFACE TEMPERATURE anomaly data from November 1981 to March 2012, as it is presented by the NOAA NOMADS website linked at the end of the post. I’ve added the 13-month running-average filter to smooth out the seasonal variations.

MONTHLY INDIVIDUAL OCEAN AND HEMISPHERIC SEA SURFACE TEMPERATURE UPDATES

(5) Northern Hemisphere Sea Surface Temperature (SST) Anomalies

Monthly Change = -0.026 deg C

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(6) Southern Hemisphere Sea Surface Temperature (SST) Anomalies

Monthly Change = -0.009 deg C

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(7) North Atlantic Sea Surface Temperature (SST) Anomalies

(0 to 70N, 80W to 0)

Monthly Change = -0.039 deg C

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(8) South Atlantic Sea Surface Temperature (SST) Anomalies

(0 to 60S, 70W to 20E)

Monthly Change = +0.095 deg C

Note: I discussed the (now apparently temporary) upward shift in the South Atlantic Sea Surface Temperature anomalies in the post The 2009/10 Warming Of The South Atlantic. It looks as though the South Atlantic sea surface temperature anomalies MAYreturn to the level they were at before that surge, and where they had been since the late 1980s. We’ll have to see where things settle.

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(9) North Pacific Sea Surface Temperature (SST) Anomalies

(0 to 65N, 100E to 90W)

Monthly Change = -0.031 Deg C

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(10) South Pacific Sea Surface Temperature (SST) Anomalies

(0 to 60S, 120E to 70W)

Monthly Change = -0.004 deg C

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(11) Indian Ocean Sea Surface Temperature (SST) Anomalies

(60S to 30N, 20E to 120E)

Monthly Change = -0.116 deg C

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(12) Arctic Ocean Sea Surface Temperature (SST) Anomalies

(65N to 90N)

Monthly Change = -0.031 deg C

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(13) Southern Ocean Sea Surface Temperature (SST) Anomalies

(90S-60S)

Monthly Change = +0.140 deg C

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WEEKLY SEA SURFACE TEMPERATURE ANOMALIES

The weekly NINO3.4 Sea Surface Temperature (SST) Anomalies have risen well above the threshold of a La Niña event. The NINO3.4 Sea Surface Temperature anomaly based on the week centered on April 4, 2012 is -0.262 deg C.

(14) Weekly NINO3.4 Sea Surface Temperature (SST) Anomalies

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The weekly global Sea Surface Temperature anomalies dropped a little over the past few weeks and are now at +0.116 deg C.

(15) Weekly Global Sea Surface Temperature (SST) Anomalies

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MY FIRST BOOK

I referred to my recently published book a few times in this post. It is available in pdf and Kindle formats. See If the IPCC was Selling Manmade Global Warming as a Product, Would the FTC Stop their deceptive Ads? A copy of the introduction, table of contents, and closing can be found here. Of course, donations are welcome and gratefully accepted, because the rumor that bloggers skeptical of anthropogenic climate change are supported by big oil is simply that, a rumor.

SOURCES

The Reynolds 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

The CMIP3 Sea Surface Temperature data (identified as TOS, assumedly for Temperature of the Ocean Surface) is available through the KNMI Climate Explorer Monthly CMIP3+ scenario runs webpage.