GHRSST Reanalysis/GCOS SST-SI Intercomparisons

The goal of the Global Climate Observing System's (GCOS) SST and Sea Ice (SI) Working Group is to understand differences between different SST analyses and reconstructions with the aim of producing better, long-term SST climate data records. By working in the context of the GHRSST Reanalysis effort, a second goal of linking the modern satellite-based records with the historical, primarily in situ - based records can be accomplished.

For modern, satellite-based products, this group has chosen an initial focus on weekly, one degree versions of the data sets as well as monthly, five degree versions. For the historical products, the group focuses on monthly, five degree versions of the data sets. The first milestone of this intercomparison effort is to provide each of the data sets on a common grid and in common, widely-used formats. Secondly, in order to quantitatively evaluate the differences between SST analyses, a set of standard diagnostics is calculated for each data set. These diagnostics are organized into two phases: the first evaluates each data set both with respect to the data set's own climatology and with respect to a common climatology; the second evaluates each data set with respect to every other data set. In the case of the satellite era diagnostics, the common climatology used is AVHRR Pathfinder V5, Quality Flag 7, from 1985-2007. For the historical diagnostics, the Hadley Centre SST V2 climatology from 1961-1990 was used.

Go to Descriptive Diagnostics for:	Go to Intercomparison Diagnostics for:
Satellite Era (1981 - 2007)	Satellite Era (1981 - 2007)
Historical Data (1850 - 2008)	Historical Data (1850 - 2008)
Descriptive Diagnostics include: Standard deviation of anomalies in time Linear trend of anomalies in time (historical data sets only) Lag1 autocorrelation of anomalies in time (coming soon) Time series of global and hemispheric anomalies Time-latitude sections of anomalies	Intercomparison Diagnostics include: Map of root mean square (RMS) differences Map of time-averaged differences Time series of global and hemispheric anomalies (historical data sets only) Time-latitude sections of differences (historical data sets only)

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