Validation and Application of Satellite Derived Sea Surface Temperature Gradients in the Bering Strait and Bering Sea

The Arctic is one of the most important regions of the world’s oceans for understanding the impacts of a changing climate. Yet, it is also difficult to measure because of extreme weather, as well as ice conditions. In this work we directly compare four data sets from the Group for High Resolution Sea Surface Temperature (GHRSST) with a NASA Saildrone deployment along the Alaskan Coast and the Bering Sea and Bering Strait. The four data sets used were the Remote Sensing Systems Microwave Infrared Optimally Interpolated (MWIR) Product, the Canadian Meteorological Center (CMC) product, the Daily Optimally Interpolated Product (DOISST) and the Operational Sea Surface Temperature and Ice Analysis (OSTIA) Product. Spatial sea surface temperature (SST) gradients were derived for both the Saildrone deployment and the GHRSST products, with the GHRSST products collocated with the Saildrone deployment. Overall, statistics indicate that the OSTIA product had the best correlation of 0.79 and a root mean square difference of 0.11°C/km when compared with Saildrone. Differences increased at latitudes > 65° N where sea ice would have a greater impact. A trend analysis was then performed on the gradient fields. Overall positive trends in gradients occurred in areas along the coastal regions. A negative trend occurred at approximately 60° N. A major result of the study indicates that future work needs to revolve around the impact of changing ice conditions on SST gradients. A major result is that a northward shift in the southern ice edge occurred after 2010 with a maxima at approximately 2019. Future work needs to revolve around examining possible causes for the northward shift.