Diurnal sea surface temperature warming and its impact on mesoscale air-sea interaction in a coastal area

The authors estimated daily sea surface temperature (SST) amplitude over the western Pacific using satellite-derived data only, and revealed that in coastal areas around Japan, large SST warming occurred with particularly high frequency in summer. The authors then investigated air-sea interaction related with the SST warming in Mutsu Bay using a mesoscale air-sea coupled model. The daily SST amplitude can exceed 5 K under a clear and calm condition. Such sea surface warming weakens land-sea temperature contrast. As a result, horizontal negative heat transfer by sea breeze is weakened and air temperature above land near the coast becomes higher by about 1 K than that without air-sea coupling. This result indicates that the large diurnal SST warming can have a non-negligible impact on air temperature prediction in coastal regions.