Comparison of Underway-CTD in situ and satellite data during the SPURS-2 campaign over the period August 2016 to November 2017. (Top left) Underway-CTD sea surface salinity (SSS) data overlays the SSS map from SMAP RSS Level 3 V4 8-day running mean. (Top right) Underway-CTD SSS data (red line), SMAP SSS data (white line). (Bottom left) Underway-CTD sea surface temperature (SST) data overlays the SST map from GHRSST Level 4 MUR V4.1. (Bottom right) Underway-CTD SST (red line), MUR SST (white line). (Underway-CTD DOI: 10.5067/SPUR2-PCO20; SMAP SSS DOI: 10.5067/SMP40-3SPCS; MUR SST DOI: 10.5067/GHGMR-4FJ04).