Comparison between the Pathfinder Versions 5.0 and 4.1 Sea Surface Temperature Datasets: A Case Study for High Resolution

Abstract

Two Pathfinder sea surface temperature (SST) datasets?version 5.0 (V50) and version 4.1 (V41)?were compared in two test areas: 1) the Gulf Stream (GS) between 35° and 43°N, 75° and 60°W and 2) the California coast (CC) between 30° and 45°N, 130° and 120°W. Using a nearest-neighbor approach, V50 data were regridded to the lower resolution V41 9-km data. The V50 and V41 versions were also independently compared with data from the World Ocean Database (WOD). Climatological monthly rms differences between V50 and V41 were calculated as well as seasonal differences between V50, V41, and the WOD. Maximum rms differences of 0.8°C between the V50 and V41 were seen in June for the GS. In the CC maximum differences of 0.4°C were seen in July. Significant seasonal trends were evident in rms differences between V41 and the WOD, with a maximum of 1.5°C occurring in the GS in June and in the CC in July. No seasonal peaks occurred in the rms differences between V50 and the WOD. SST gradients were calculated using both V50 and V41 datasets. Maximum climatological SST gradients were seen in the June time frame for the GS and July for the CC, consistent with the largest rms differences compared to the WOD. Results indicate the importance of projects such as the Group for High-Resolution Sea Surface Temperature (GHRSST) and the creation of high-resolution SST datasets for resolving air?sea interactions, specifically in areas of strong SST gradients.