Adequacy of the In Situ Observing System in the Satellite Era for Climate SST

Huai-Min Zhang, Richard W. Reynolds, Thomas M. Smith
2006 Journal of Atmospheric and Oceanic Technology  
A method is presented to evaluate the adequacy of the recent in situ network for climate sea surface temperature (SST) analyses using both in situ and satellite observations. Satellite observations provide superior spatiotemporal coverage but with biases; in situ data are needed to correct the satellite biases. Recent NOAA/U.S. Navy operational AVHRR satellite SST biases were analyzed to extract typical bias patterns and scales. Occasional biases of 2 o C were found during large volcano
more » ... s and near the end of the satellite instruments' lifetime. Since future biases could not be predicted, the in situ network was designed to reduce the large biases that have occurred to a required accuracy. Simulations with different buoy density were used to examine their ability to correct the satellite biases and to define the residual bias as a potential satellite bias error (PSBE). The PSBE and buoy density (BD) relationship was found to be nearly exponential, resulting in an optimal BD range of 2-3/10 o x10 o box for efficient PSBE reduction. A BD of 2 buoys/10ºx10 o reduces a 2 o C maximum bias to below 0.5 o C and reduces a 1 o C maximum bias to about 0.3 o C. The present in situ SST observing system was evaluated to define an equivalent buoy density (EBD), allowing ships to be used along with buoys according to their random errors. Seasonally averaged monthly EBD maps were computed to determine where additional buoys are needed for future deployments. Additionally, a PSBE was computed from the present EBD to assess the in situ system's adequacy to remove potential future satellite biases.
doi:10.1175/jtech1828.1 fatcat:js356nqvdbdmtpg2hfv76o33gu