Comparison of GHRSST SST analysis in the Arctic Ocean and Alaskan coastal waters using saildrones: Application to a use case in the Y-K Delta

Short abstract

There is high demand for complete satellite SST maps (or L4 SST analyses) of the Arctic regions to monitor the rapid environmental changes occurring at high latitudes. Although there is a plethora of L4 SST products to choose from, satellite-based products evolve constantly with the advent of new satellites and frequent changes in SST algorithms with the intent of improving absolute accuracies.  The constant change of these products, as reflected by the version product, make it necessary to do periodic validations against in situ data.  Eight of these L4 products are compared here against saildrone data from two 2019 campaigns in the western Arctic, as part of the MISST project. The accuracy of the different products is estimated using different statistical methods, from standard and robust statistics to Taylor diagrams.  Results are also examined in terms of spatial scales of variability using spectral analysis.  The three products with the best performance at this point and time are used in a case study of the thermal features of the Yukon-Kuskokwim delta. Comparisons are also made with Salinity data from NASA’s Soil Moisture Active Passive Mission. Overall, the statistical analyses show that two L4 SST products had consistently better relative accuracy when compared to the saildrone subsurface temperatures. Those are the NOAA/NCEI DOISST and the RSS MWOI SSTs.  Results will also be presented on comparing the spectral variance and feature resolution. Comparisons are all done using Saildrone as the reference