抄録
In this study, a regional climate model (WRF-ARW; the Advanced Research Weather Research and Forecasting model) having a resolution of 4.5 km was used to examine the sensitivity of precipitation on the Japan Sea side of Japan to the sea surface temperature (SST) in the Japan Sea during winter. We performed a control simulation (CTL) driven by reanalysis and observational SST datasets. Three sensitivity experiments in which SSTs over the entire domain were 1K, 2K, and − 1K different from the CTL SST were conducted to examine the sensitivity of precipitation to SST. The calculated precipitation on the Japan Sea side increased by 6-12% K−1 of SST warming. Concurrent with the precipitation changes, latent heat flux over the Japan Sea increased by 11-14% K−1 of SST warming. Because the changes in surface relative humidity were very small, the increase can be explained by the Clausius-Clapeyron equation. The deviation from the 7% increase in latent heat flux calculated from this equation can be quantitatively explained by the development of the planetary boundary layer over the Japan Sea, which was related to an increase in sensible heat flux due to the SST warming. This result also implies that the 1 K uncertainty in simulated and projected SST over the Japan Sea among multiple atmosphere-ocean global climate models corresponds to an approximately 10% uncertainty in precipitation on the Japan Sea side of Japan.
