Fine-resolution satellite-based daily sea surface temperatures over the global ocean

[1] The accuracy and relative merits of two sets of daily global sea surface temperature (SST) analyses are examined and compared. The 1/8 Modular Ocean Data Analysis System (MODAS) of the Naval Research Laboratory (NRL) is based only on infrared satellite retrievals. The 1/2 Real-Time, Global (RTG) SST analysis of the National Centers for Environmental Prediction (NCEP) supplements infrared satellite observations with ship and buoy data. The accuracy of both products is reported, providing potential users of either data set a common basis to assess the strengths and weaknesses of either product. Differences between the two show the impact of horizontal resolution, inclusion of source data streams, and different assumptions regarding error covariances. The global average of the root-mean-square (RMS) SST difference between MODAS and RTG is found to be 0.51 C, with almost no mean bias. A global set of yearlong daily SST time series from moored buoys during 2002–2005 provides extensive validation data for this study. Comparisons at the locations of these 420 yearlong time series give a median RMS SST difference of 0.40 C between MODAS and RTG. RMS error relative to the buoy observations is comparable, 0.38 C for MODAS and 0.36 C for RTG. The seasonal cycle of SST is well produced by both products with respect to the buoys with a median correlation coefficient of 0.94 for both products. Overall, higher resolution is an advantage for MODAS in improving pattern of daily SSTs, while including in situ SSTs is an advantage for RTG.