Guest Post by: Craig Loehle
In the paper
Levitus S., J. I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, A. V. Mishonov (2009), Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems,Geophys. Res. Lett., 36, L07608, doi:10.1029/2008GL037155
the long term trend of ocean heat content is reanalyzed to attempt to correct for bias in instrumentation, and the record is extended. The graph below depicts the result.
The most recent period, from 2003, uses the ARGO profiling floats, whereas earlier periods use a variety of instruments with various biases. Patching all these data together is a challenge. I draw your attention to the strong spike in the red line from 2002 to 2003. This line is the point at which the earlier data is joined up with the ARGO data. The magnitude of the jump is the largest in the entire record. The transition to the ARGO data can not be said to have been accomplished with a long cross-calibration period. It thus looks to me like there may be an error in how the different data sets are stitched together. I in no way am implying malfeasance here. I have discussed this situation with Roger Pielke Sr. and Josh Willis and they agree it looks odd and merits further investigation. Dr. Pielke points out that there is not a comparable jump in the SST data. I think this example illustrates that if there is a big jump in the data right when you change your instrumentation, it is perhaps good to look a little closer.
Further discussion of the paper is available at Pielke’s site: