Evaluation of the relative performance of sea surface temperature measurements from different types of drifting and moored buoys using satellite-derived reference products

Sea surface temperature (SST) measurements from drifting and moored buoys have been used extensively to validate satellite SST products. Previous efforts explored overall uncertainties in the buoy measurements, but did not quantify differences in the performance of different buoy types. Here, drifting and moored buoys stratified into open-ocean and coastal, were evaluated by manufacturer (drifters) and buoy program (moorings) to identify significant deviations in their suitability for satellite validation. Biases and standard deviations were computed for differences between the buoy SST measurements and two satellite references: the Advanced Microwave Scanning Radiometer SST product from Remote Sensing Systems and the U. S. Naval Oceanographic Office K10 analysis. No significant differences were found among the various drifting and tropical moored buoys, regardless of the manufacturer/program. The largest deviations were observed for the non-tropical moored buoys possibly in part due to calibration differences. In general, coastal buoys exhibited greater standard deviations associated with increased physical variability within the coastal regions. Tropical moored buoys showed smaller standard deviations than for the drifters resulting from better quality measurements or reduced variability in the tropics. Large deviations between the coastal moorings and the SST references appeared linked to coastal currents with upwelling, rather than buoy performance. Coastal moorings provided sampling of small-scale coastal variability, not resolved in satellite products, offering the potential for improving poorly parameterized coastal SSTs. Differences due to diurnal warming were largely eliminated by constraining collocations between the satellite and the buoy to +/- 1 h. Overall, most buoy types appear suitable for satellite SST validation.