On the Warming Events over Toyama Plain by Using NHRCM

The climatological features of warming events over Toyama Plain and the heating mechanisms are investigated by using observation and the non-hydrostatic regional climate model NHRCM. Warming events are frequently observed in March and April. The 20 km-NHRCM can reproduce the seasonal variation of the frequency of warming events. In spite of the large diversity of heating mechanisms in the warming events, typical warming factors are apparent, and the ratio of contribution differs case by case. The results of the 10 km-NHRCM and backward trajectory analysis indicate that these factors are moist-adiabatic processes, dry-adiabatic processes, and sunshine insolation. The frequency of the typical insolation event is quite low, but it often accelerates warming with other factors. The NHRCM demonstrates high potential for the application of local climate studies as a dynamical downscaling tool.