October 2008 SST Update

OPENING NOTES: All but the graph of weekly NINO3.4 SST anomalies are based on ERSST.v2 data. They illustrate raw monthly data from January 1978 to October 2008. The graph of weekly NINO3.4 SST anomalies is based on OI.v2 SST data and illustrates raw weekly data that’s centered on Wednesdays.

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Sorry for the delay, but NOMADS was off line for a few days early in the week and I got sidetracked with a few other posts.

I’ve elected to eliminate the Southern Oscillation Index (SOI) updates. At times, NINO3.4 SST anomalies don’t follow the SOI precisely, so the SOI can be misleading with respect to the overall direction of NINO3.4 SST. In its place, I’ve added the weekly Optimally Interpolated Sea Surface Temperature (OI.v2 SST) data for the NINO3.4 region.

NINO3.4 SST ANOMALIES BASED ON WEEKLY OI.v2 SST DATA

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NINO3.4 SST Anomaly (OI.v2 SST)

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MONTHLY ERSST.v2 UPDATES

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NINO3.4 SST Anomaly – Monthly Change = +0.187 deg C

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Global SST – Monthly Change = +0.056 deg C

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Northern Hemisphere – Monthly Change = +0.099 deg C

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Southern Hemisphere – Monthly Change = +0.022 deg C

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North Atlantic (0 to 75N, 78W to 10E) – Monthly Change = -0.038 deg C

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South Atlantic (0 to 60S, 70W to 20E) – Monthly Change = +0.030 deg C

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North Pacific (0 to 65N, 90 to 180W) & (0 to 65N, 100 to 180E) –
Monthly Change = +0.145 deg C

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South Pacific (0 to 60S, 70 to 180W) & (0 to 60S, 145 to 180E) –
Monthly Change = +0.061 deg C

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Indian Ocean (30N to 60S, 20 to 145E) – Monthly Change = +0.010 deg C

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Arctic Ocean (65 to 90N) – Monthly Change = +0.302 deg C

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Southern Ocean (60 to 90S) – Monthly Change = +0.047 deg C

SOURCE

Smith and Reynolds Extended Reconstructed SST Sea Surface Temperature Data (ERSST.v2) and the Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).
http://nomads.ncdc.noaa.gov/#climatencdc

The Ishii and Kimoto Proposed Update to Ocean Heat Content

AND A CURIOUS COINCIDENCE?

The November 5, 2008, NASA Earth Observatory article “Correcting Ocean Cooling” renewed interest in Ocean Heat Content at Jennifer Marohasy’s blog with her post Correcting Ocean Cooling: NASA Changes Data to Fit the Models.

NASA Earth Observatory Article:
http://earthobservatory.nasa.gov/Features/OceanCooling/

If you search the comments on the Jennifer Marohasy thread, you can find my second attempt to post a comment with links. Unfortunately, Jennifer’s spam blocker discarded my “working version”. This post is an expansion of my post there, with copies of the Ocean Heat Content graph from the paper I linked.

About the same time the NASA article was published, I discovered a paper “Reevaluation of Historical Ocean Heat Content Variations With An XBT Depth Bias Correction” (2008), in which Ishii and Kimoto proposed a bias correction methodology that resulted in the following Ocean Heat Content graph, Figure 6 from the paper.

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Ishii and Kimoto Figure 6

Link to the Ishii and Kimoto paper:
http://atm-phys.nies.go.jp/~ism/pub/ProjD/doc/Ishii-Kimoto-2008.pdf

I highlighted the proposed update in red in the following.
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Ishii and Kimoto Figure 6 with Proposed OHC Corrections Highlighted

The Abstract of the paper includes: “In comparison with the previous temperature analysis, large differences are found in the present analysis as follows; the duration of large ocean heat content in the 1970s shortens dramatically, the global warming trend decreases, and recent ocean cooling becomes insignificant.”

Ishii and Kimoto end the differences with “and recent ocean cooling becomes insignificant”, but the clause before that “the global warming trend decreases” is significant. They explain on page 10: “The OHC trend of the present analysis for 1955-2005 becomes smaller by 20% than in ver. 6.2, while that for recent 13 years (1993-2005) becomes larger by 70%. These changes in global warming trends are substantial.” The reason for the substantial increase in trend from 1993 to 2005 is the major downward correction in Ocean Heat Content from 1991 to 1997. It wasn’t due to an increase, because most of the upward correction from 2003 through 2006 was not included in the trend.

Therefore, the decrease in the long-term trend of 20% is, in my opinion, the significant difference.

A CURIOUS COINCIDENCE?

UPDATE (November 14, 2008): Please note that I am not implying any wrongdoing on the parts of those who calculate Ocean Heat Content. I simply found the following to be an odd coincidence, one that should be discussed.

The following is a graph of the number of global ocean data profiles accumulated monthly from 1979 to 2006 by the NCEP Global Ocean Data Assimilation System for a depth of 0-250 Meters from 90S to 90N. It’s odd that in recent years the Ocean Heat Content rises above its previous high in the 1970s, while at the same time the number of subsurface ocean temperature readings increases drastically. Then the Ocean Heat Content peak and decline about the same time as the number of readings.
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Number of Global Ocean Data Profiles

The Climate Prediction Center NCEP Global Ocean Data Assimilation System: Monthly Products webpage is here:
http://www.cpc.noaa.gov/products/GODAS/data_distribution.shtml

NINO3.4 SST & Warm Water Volume & Subsurface Temperature

This just a quick post to illustrate the correlation between the following three data sets:
- NINO3.4 SST Anomaly,
- East Equatorial Pacific Warm Water Volume Anomaly, and
- East Equatorial Pacific Subsurface Temperature Anomaly.

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Figure 1

The NINO3.4 SST anomaly data is for the area with the coordinates 5S to 5N, 170W to 120W. The East Equatorial Pacific Warm Water Volume represents the volume of water with temperature above 20 Deg C in the tropical Pacific between 5°N to 5°S, 155W to 80W. The East Equatorial Pacific Subsurface Temperature Anomaly is the average temperature (Deg C) in the upper 300 Meters of the slice of the equator between 180W and 100W.

The data did not have to be scaled. The graph represents the raw data.

The Subsurface Temperature Anomaly data has not been updated since April 2008, but the Warm Water Volume data appears to be updated possibly on weekly basis, with the current month being an average of values to date.

I discussed the Equatorial Pacific Subsurface Temperature Anomaly data here:
http://bobtisdale.blogspot.com/2008/11/average-subsurface-temperature-of.html

And I discussed the Equatorial Pacific Warm Water Volume data here:
http://bobtisdale.blogspot.com/2008/11/equatorial-pacific-warm-water-volume.html

SOURCES


The Warm Water Volume data is available from the Tropical Atmosphere Ocean (TAO) Project Office of the NOAA Pacific Marine Environmental Laboratory webpage titled “Warm Water Volume and ENSO”. http://www.pmel.noaa.gov/tao/elnino/wwv/



The Equatorial Pacific Subsurface Temperature anomaly data is referred to as Equatorial Upper-Ocean Heat Content Anomalies(1979-present) by the National Weather Service Climate Prediction Center (CDC here: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/enso.shtml


Sea Surface Temperature Data is Smith and Reynolds Extended Reconstructed SST (ERSST.v2) available through the NOAA National Operational Model Archive & Distribution System (NOMADS).http://nomads.ncdc.noaa.gov/#climatencdc