personal player football: Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World

I’ve moved to WordPress. This post can now be found at Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World

################
I will be adding two volcano-adjusted SST anomaly subsets to the monthly updates starting with the February 2011 update. They are the East Pacific, which mimics NINO3.4 SST anomalies, and the Rest of the World, which rises in very clear steps during significant ENSO events.

You may want to bookmark the LINKS TO SST ANOMALY UPDATES for future reference.

INTRODUCTION

I’ve written numerous posts about the upward steps in the Sea Surface Temperature (SST) anomalies of the East Indian-West Pacific Oceans (60S-65, 80E-180). Many of them are linked at the end if this post under the heading of “Further Discussions”. In an upcoming post, which is a continuation of my Comments On Tamino’s AMO Post, I’ll also be illustrating and discussing similar upward steps in the Atlantic Multidecadal Oscillation (AMO) data, which are detrended North Atlantic SST data (0-70N, 80W-0). Refer to Figure 1, which is a .gif animation. As illustrated, ENSO- and Volcano-adjusted AMO data rise in steps during the transitions from El Niño to La Niña, but between the upward steps, they mimic the inverted NINO3.4 SST anomalies.

http://i56.tinypic.com/2repfo0.jpg
Figure 1

Similar upward steps can also be illustrated if we divide the global oceans into two subsets so that one of them contains both the North Atlantic and the East Indian-West Pacific datasets. The two subsets, Figure 2, are the East Pacific Ocean (90S-90N, 180W-80W) and the Rest Of The World (90S-90N, 80W-180E), the latter of the two containing the North Atlantic and East Indian-West Pacific datasets. As we shall see, the East Pacific SST anomalies mimic the variations of ENSO proxies, with little trend, while the SST anomalies of the Rest of the World rise in very clear steps that coincide with the 1986/87/88 and 1997/98 El Niño events.

http://i53.tinypic.com/141qcyd.jpg
Figure 2

ACCOUNTING FOR THE IMPACTS OF VOLCANIC ERUPTIONS
I’ll be removing the linear effects of the two major volcanic eruptions, El Chichon and Mount Pinatubo, from the two SST datasets. To determine the scaling factor for the volcanic aerosol proxy, I used a linear regression software tool (Analyse-it for Excel) with global SST anomalies as the dependent variable and GISS Stratospheric Aerosol Optical Thickness data (ASCII data) as the independent variable. The scaling factor determined was 1.431. This equals a global SST anomaly impact of approximately 0.2 deg C for the 1991 Mount Pinatubo eruption. Refer to Figure 3. I’ll use that scaling factor for the East Pacific and Rest of the World datasets.

http://i55.tinypic.com/33acpwp.jpg
Figure 3

EAST PACIFIC
As shown in Figure 4, the Volcano-adjusted East Pacific SST anomalies vary in concert with the scaled NINO3.4 SST anomalies. There are periodic divergences, but the variations in the East Pacific SST anomalies mimic the commonly used ENSO proxy.

http://i53.tinypic.com/2zi4ig2.jpg
Figure 4

The linear trend for the East Pacific SST anomalies since November 1981 is basically flat, at only 0.08 deg C per Century. Refer to Figure 5.

http://i56.tinypic.com/1565ldz.jpg
Figure 5

This obviously means the rise in the global SST anomalies since the start if this satellite-based SST dataset must occur outside of the East Pacific.

REST OF THE WORLD

Figure 6 compares the SST anomalies and the linear trends of the East Pacific and the Rest Of the World. Since November 1981, the SST anomalies of the Rest of the World (90S-90N, 80W-180) have risen at a rate of approximately 1.01 deg C per Century, while the trend of the East Pacific SST anomalies is only 0.08 deg C per Century.

http://i55.tinypic.com/2mxh9pf.jpg
Figure 6

The East Pacific data used in this post represent approximately 33% of the global ocean surface area. (The percentage is based on the NCEP/DOE Reanalysis-2 “Land Mask” data available through the KNMI Climate Explorer.) So we can place the two datasets in perspective by scaling the East Pacific data by a factor of 0.5. Refer to Figure 7. Notice how flat the Rest of the World SST anomalies are after the 1997/98 upward shift. There are some minor fluctuations, but the Rest of the World SST anomalies are essentially flat until 2009/10. Backing up in time, the same could be said for the period from 1987/88 and 1997/98; the volcano-adjusted Rest of the World data also have not risen over that period.

http://i55.tinypic.com/15hgy0j.jpg
Figure 7

Adding period-average values to the Rest Of The World SST anomalies, Figure 8, makes the upward steps stand out even more. It will be interesting to see where the “July 2009 to Present” SST anomaly average settles out, if it does before the next significant El Niño drives them higher.