Guest post by Bob Tisdale
The National Oceanographic Data Center (NODC) recently updated its 4th quarter and annual 2009 Ocean Heat Content (OHC) data. The data that was presented in conjunction with the Levitus et al (2009) Paper now covers the period of 1955 to 2009. There have been changes that some might find significant.
This post presents:
1. A brief look at the revisions (corrections) to the data in 2007 and 2008 OHC data
2. A comparison of the NODC OHC data for the period of 2003 to 2009 versus the GISS projection
REVISIONS (Corrections) TO THE 2007 AND 2008 NODC OHC DATA
Figure 1 is a gif animation of two Ocean Heat Content graphs posted on the NODC GLOBAL OCEAN HEAT CONTENT webpage. It shows the differences between the current (January 2010) version and one that appears to include data through June or September 2009. So this is an “Official” correction (not more incompletely updated data posted on the NODC website discussed in NODC’s CORRECTION TO OHC (0-700m) DATA, which required me to make corrections to a handful of posts). I have found nothing in the NODC OHC web pages that discuss these new corrections. Due to the years involved, is it safe to assume these are more corrections for ARGO biases? As of this writing, I have not gone through the individual ocean basins to determine if the corrections were to one ocean basin, a group of basins, or if they’re global; I’ll put aside the multipart post I’ve been working on for the past few weeks and try to take a look over the next few days.
NODC OHC OBSERVATIONS VERSUS GISS PROJECTION (2003-2009)
One of the posts that needed to be corrected back in October was NODC Ocean Heat Content (0-700 Meters) Versus GISS Projections (Corrected). The final graph in that post was a comparison of global ocean heat content observations for the period of 2003 through year-to-date 2009 versus the projection made by James Hansen of GISS of an approximate accumulation of 0.98*10^22 Joules per year. Figure 2 is an updated version of that comparison. Annual Global OHC data was downloaded from the NODC website (not through KNMI). The trend of the current version of the NODC OHC data is approximately 1.5% of the GISS projection. That is, GISS projected a significant rise, while the observations have flattened significantly in recent years. The apparent basis for the divergence between observations and the GISS Projection was discussed in the appropriately titled post Why Are OHC Observations (0-700m) Diverging From GISS Projections?
Note: The earlier version of that graph (with the NODC’s October 15, 2009 correction)…
…shows a linear trend of ~0.08*10^22 Joules/year. The current linear trend is ~0.015*10^22 Joules/year. Some might consider that decrease to be significant.
NOTE: I DELETED THE THIRD AND FOURTH PARTS OF THIS POST…
3. GLOBAL, HEMISPHERIC, AND INDIVIDUAL BASIN OHC UPDATE THROUGH DECEMBER 2009, AND
4. TREND COMPARISONS
…UNTIL I TRACK DOWN DISCREPANCIES I CAN’T EXPLAIN. I WILL REPOST THOSE SECTIONS IN A NEW POST. I BELIEVE I UNDERSTAND THE DIFFERENCES, BUT I NEED TO CHECK WITH KNMI.
NODC Annual Global OHC data used in Figure 2 is available here: