Daytime vs nighttime AVHRR sea surface temperature data: A report regarding Wellington et al. (2001)

A recent study by Wellington et al. (2001) excluded daytime and selected only nighttime AVHRR sea surface temperature (SST) data for comparison with in situ observations, citing two studies to support this decision. One of these studies is incorrectly referenced since it does not discuss day-night satellite data issues, and the other supports the use of nighttime AVHRR data based on biases with a single buoy recording SST in a different ocean basin. This report discusses the diffculty in selecting only daytime or nighttime AVHRR data based on dissimilar studies owing to highly variable satellite SST biases and differences in satellite processing algorithms. Additionally, it presents a simple analysis based on co-located satellite and in situ data which highlights two important processes affecting the day-night satellite SST differences: diurnal warming and the skin effect.