May 2015 Sea Surface Temperature (SST) Anomaly Update

MONTHLY SEA SURFACE TEMPERATURE ANOMALY MAP

The following is a Global map of Reynolds OI.v2 Sea Surface Temperature (SST) anomalies for May 2015.  It was downloaded from the KNMI Climate Explorer. The contour range was set to -2.5 to +2.5 deg C.

May 2015 Sea Surface Temperature (SST) Anomalies Map

(Global SST Anomaly = +0.291 deg C)

MONTHLY GLOBAL OVERVIEW

Global Sea Surface Temperature anomalies took another upswing in May, an increase of about +0.04 deg C from April to May. The Northern Hemisphere showed a sizeable warming, while there was basically no change in the Southern Hemisphere. With the exceptions of the South Pacific and Southern Oceans, all ocean basins showed warming.  As the El Niño continues to develop, we should expect those increases around the globe.  The monthly Global Sea Surface Temperature anomalies are presently at +0.291 deg C, referenced to the WMO-preferred base years of 1981 to 2010.

(1)Global Sea Surface Temperature Anomalies

Monthly Change = +0.042 deg C

THE EQUATORIAL PACIFIC

The NINO3.4 Sea Surface Temperature anomalies for May 2015 have risen above the +1.0 deg C threshold of a moderate El Nino.  They are presently at +1.08 deg C, having increased about +0.26 deg C since April.

(2) NINO3.4 Sea Surface Temperature Anomalies

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

Monthly Change = +0.259 deg C

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The sea surface temperature anomalies for the NINO3.4 region in the east-central equatorial Pacific (5S-5N, 170E-120E) are a commonly used index for the strength, frequency and duration of El Niño and La Nina events.  We keep an eye on the sea surface temperatures there because El Niño and La Niña events are the primary cause of the yearly variations in global sea surface temperatures AND they are the primary cause of the long-term warming of global sea surface temperatures over the past 30 years.   See the discussion of the East Pacific versus the Rest-of-the-World that follows.  We present NINO3.4 sea surface temperature anomalies in monthly and weekly formats in these updates.

Also see the weekly data toward the end of the post.

INITIAL NOTES

Note 1: Because the NOMADS servers are off line, I’ve downloaded the Reynolds OI.v2 data from the KNMI Climate Explorer, using the base years of 1981-2010.  The updated base years help to reduce the seasonal components in the ocean-basin subsets—they don’t eliminate those seasonal components, but they reduce them.

Note 2: We discussed the reasons for the elevated sea surface temperatures in the post On The Recent Record-High Global Sea Surface Temperatures – The Wheres and Whys.

Note 3:  I’ve moved the model-data comparison to the end of the post.

Note 4: I recently added a graph of the sea surface temperature anomalies for The Blob in the eastern extratropical North Pacific. It also is toward the end of the post.

THE EAST PACIFIC VERSUS THE REST OF THE WORLD

NOTE:  This section of the updates has been revised.  We discussed the reasons for the changes in the post Changes to the Monthly Sea Surface Temperature Anomaly Updates.

For years, we have shown and discussed that the surfaces of the global oceans have not warmed uniformly during the satellite era of sea surface temperature data. In fact, some portions of the global oceans have cooled during that 3+ decade period.   One simply has to look at a trend map for the period of 1982 to 2013 to see where the ocean surfaces have warmed and where they have not.  Yet the climate science community has not addressed this.  See the post Maybe the IPCC’s Modelers Should Try to Simulate Earth’s Oceans.

The North Atlantic (data illustrated later in the post) has had the greatest warming over the past 3+ decades, but the reason for this is widely known.  The North Atlantic has an additional mode of natural variability called the Atlantic Multidecadal Oscillation.  If you’re not familiar with the Atlantic Multidecadal Oscillation see the NOAA Frequently Asked Questions About the Atlantic Multidecadal Oscillation (AMO) webpage and the posts An Introduction To ENSO, AMO, and PDO — Part 2 and Multidecadal Variations and Sea Surface Temperature Reconstructions.  As a result of the Atlantic Multidecadal Oscillation, the surface of the North Atlantic warmed at a rate that was more than twice the rate of the surface of the rest of the global oceans.  See the trend comparison graph here.

The East Pacific Ocean also stands out in the trend map above.  Some portions of its surfaces warmed and others cooled.  It comes as no surprise then that the linear trend of the East Pacific (90S-90N, 180-80W) Sea Surface Temperature anomalies since the start of the Reynolds OI.v2 dataset is so low.  With the El Nino conditions in the eastern tropical Pacific, it has acquired a slight positive trend, but it’s still far below the approximate +0.15 deg C/decade warming rate predicted by the CMIP5 climate models. Please see Figure 19 in the post Maybe the IPCC’s Modelers Should Try to Simulate Earth’s Oceans. (Note that the region also includes portions of the Arctic and Southern Oceans.)  That is, there has been little to no warming of the sea surfaces of the East Pacific (from pole to pole) in 32 years.  The East Pacific is not a small region.  It represents about 33% of the surface area of the global oceans. The East Pacific linear trend varies very slightly with each monthly update.  But it doesn’t vary greatly between El Niño and La Niña events.

Notice how there appears to have been a strong El Niño event this year in the East Pacific data, while there has only been a small off season event so far this year.  Note also how there appears to have been a shift in the data in 2013. Refer again to the post On The Recent Record-High Global Sea Surface Temperatures – The Wheres and Whys. The other ocean basins, thankfully, are not responding as if there has been an El Niño.

(3) East Pacific Sea Surface Temperature (SST) Anomalies

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

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That leaves the largest region of the trend map, which includes the South Atlantic, the Indian and West Pacific Oceans, with the corresponding portions of the Arctic and Southern Oceans.  Sea surface temperatures there warmed 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 sea surface temperature anomalies of this dataset have made another upward shift in response to the 2009/10 El Niño and 2010/11 La Niña events.  I further described the ENSO-related processes that cause these upward steps in the recent post Answer to the Question Posed at Climate Etc.: By What Mechanism Does an El Niño Contribute to Global Warming?

Again, as you’ll note, the data for the South Atlantic, Indian and West Pacific Oceans do not show anything unusual this year. (And as you’ll see later, the North Atlantic is presently showing the “normal” range of seasonal variations.) The big surge is in the East Pacific, the eastern North Pacific to be specific.

(4) Sea Surface Temperature Anomalies For The South Atlantic-Indian-West Pacific Oceans

(Weighted Average of 0-90N, 40E-180 @ 27.9% And 90S-0, 80W-180 @72.1%)

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The periods used for the average temperature anomalies for the South Atlantic-Indian-West Pacific subset between the significant El Niño events of 1982/83, 1986/87/88, 1997/98, and 2009/10 are determined as follows.  Using the original 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 South Atlantic-Indian-West Pacific Oceans, then deleted the South Atlantic-Indian-West Pacific data that corresponds to those significant El Niño events.  I then averaged the South Atlantic-Indian-West Pacific Oceans sea surface temperature anomalies between those El Niño-related gaps.

The “Nov 2010 to Present” average varies with each update.

The Sea Surface Temperature anomalies of the East Pacific Ocean, or approximately 33% of the surface area of the global oceans, have shown little to no long-term warming since 1982 based on the linear trend. And between upward shifts, the Sea Surface Temperature anomalies for the South Atlantic-Indian-West Pacific subset (about 52.5% of the global ocean surface area) remain relatively flat, though they actually cool slightly.  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 regions discussed above 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 52% but only during the months of the significant El Niño events of 1986/87/88, 1997/98 and 2009/10?

They were also discussed in great detail in my recently published book Who Turned on the Heat? The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation. The Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing. Also see the blog post Everything You Every Wanted to Know about El Niño and La Niña… for an overview. It’s now sale priced at US$5.00.  Please click here to buy a copy. (Paypal or Credit/Debit Card.  You do not need to open a PayPal account.)

STANDARD NOTE ABOUT THE DATA

The MONTHLY graphs illustrate raw monthly OI.v2 sea surface temperature anomaly data from November 1981 to May 2015, as it is presented by the KNMI Climate Explorer linked at the end of the post.  While NOAA uses the base years of 1971-2000 for this dataset, those base years cannot be used at the KNMI Climate Explorer because they extend before the actual data. (NOAA had created a special climatology for the Reynolds OI.v2 data.) I’ve referenced the data to the period of 1981 to 2010, which is actually 1982 to 2010 for most months. And I’ve added a 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 = +0.095 deg C

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

Monthly Change = +0.001 deg C

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

(0 to 70N, 80W to 0)

Monthly Change = +0.108 deg C

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

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

Monthly Change = +0.006 deg C

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(9) Pacific Sea Surface Temperature (SST) Anomalies

(60S to 65N, 120E to 80W)

Monthly Change = +0.008 Deg C

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

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

Monthly Change = +0.072 Deg C

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

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

Monthly Change = -0.033 deg C

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

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

Monthly Change = +0.098 deg C

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

(65N to 90N)

Monthly Change = +0.012 deg C

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

(90S-60S)

Monthly Change = -0.009 deg C

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WEEKLY SEA SURFACE TEMPERATURE ANOMALIES

Weekly NINO3.4 sea surface temperature anomalies are at +1.2 deg C.  They are above the +1.0 deg C threshold of a moderate El Niño.

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

Note:  With the NOMADS servers off line, I’ve used the weekly NINO3.4 data available from the NOAA/CPC Monthly Atmospheric & SST Indices webpage, specifically the data here.  They do not provide the global data on a weekly basis, so I can’t present it. Sorry.

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MODEL-DATA COMPARISON:  To counter the nonsensical “Just what AGW predicts” rantings of alarmists about the “record-high” global sea surface temperatures in 2014, I’ve added a model-data comparison of satellite-era global sea surface temperatures to these monthly updates.  See the example below.  The models are represented the multi-model ensemble-member mean of the climate models stored in the CMIP5 archive, which was used by the IPCC for their 5^th Assessment Report. For further information on the use of the model mean, see the post here. For most models, historic forcings run through 2005 (2012 for others) and the middle-of-the-road RCP6.0 forcings are used after in this comparison.  The data are represented by NOAA’s Optimum Interpolation Sea Surface Temperature data, version 2—a.k.a. Reynolds OI.v2—which is NOAA’s best.   The model outputs and data have been shifted so that their trend lines begin at “zero” anomaly for the (November, 1981) start month of this dataset. That “zeroing” helps to highlight how poorly the models simulate the warming of the ocean surfaces…almost doubling the observed warming rate.  Both the Reynolds OI.v2 data and the model outputs of their simulations of sea surface temperature (TOS) are available to the public at the KNMI Climate Explorer.

000 – Model-Data Comparison

Linked here is an illustration that compares maps of the simulated and observed warming rates of the global oceans from 1982 to 2014.  It is from the post Alarmists Bizarrely Claim “Just what AGW predicts” about the Record High Global Sea Surface Temperatures in 2014.

This addition to the monthly update was further discussed in the post The Nonsensical “Just What AGW predicts” and Other Claims By Alarmists about “Record-High” Global Sea Surface Temperatures in 2014.

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THE BLOB

After decades of no surface warming in the North Pacific as a whole, a prolonged weather event in the eastern extratropical North Pacific caused an unusual and unexpected warming there, raising sea surface temperatures in the North Pacific to new levels. That region of unusually warm sea surfaces in the eastern extratropical North Pacific has become known as The Blob.  We’ve discussed The Blob in detail in the recent post North Pacific Update: The Blob’s Strengthening Suggests It’s Not Ready to Depart.  There are links to numerous earlier discussions of the North Pacific in that post, some reaching back as far as the boreal summer of 2013.

I’ve added a graph of the sea surface temperature anomalies for The Blob region so that we can keep track of how it responds to the developing El Niño.  Keep in mind, the data for The Blob covers a relatively small part of the North Pacific, so they will be volatile.

(16) The Blob

(35N-55N, 150W-125W)

Monthly Change = -0.071 deg C

INTERESTED IN LEARNING MORE ABOUT HOW AND WHY THE GLOBAL OCEANS INDICATE THEY’VE WARMED NATURALLY?

Why should you be interested?  The hypothesis of manmade global warming depends on manmade greenhouse gases being the cause of the recent warming. But the sea surface temperature record indicates El Niño and La Niña events are responsible for the warming of global sea surface temperature anomalies over the past 32 years, not manmade greenhouse gases.  Scroll back up to the discussion of the East Pacific versus the Rest of the World.  I’ve searched sea surface temperature records for more than 4 years, and I can find no evidence of an anthropogenic greenhouse gas signal.  That is, the warming of the global oceans has been caused by Mother Nature, not anthropogenic greenhouse gases.

I’ve recently published my e-book (pdf) about the phenomena called El Niño and La Niña.  It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation.  It is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 30 years.  Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well.  The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet.  It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases.  None at all.

Who Turned on the Heat? was introduced in the blog post Everything You Ever Wanted to Know about El Niño and La Niña… …Well Just about Everything. The Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing.

Please buy a copy. (Paypal or Credit/Debit Card).  You do not need to have a PayPal account. Simply scroll down to the “Don’t Have a PayPal Account” purchase option. It’s now sale priced at US$5.00.

SOURCES

The monthly Sea Surface Temperature (SST) anomaly data and model outputs used in this post are available from the KNMI Climate Explorer.