NASA散乱計(NSCAT)で観測された寒気吹き出し時の日本海の風の収束帯

抄録

Winds are the critical factor in determining regional weather patterns and climate. In winter, the winds over the Sea of Japan have great effect on the weather of Japan islands. In this paper, wind distribution over the Sea of Japan is analyzed by using wind data observed by NASA Scatterometer (NSCAT) aboard Japan's Advanced Earth Observing Satellite (ADEOS, Midori).
Synoptic views of the wind field over the Sea of Japan show remarkable evidence of a land topography effect causing a convergence of the surface wind field during cold-air outbreaks. The Changbai mountains in the North Korea locates at upstream of outbreak winds, and the wind field is deformed by them over the western part of the Sea of Japan. Strong north winds and northwesterly winds of about 15-20 m/s are observed off Vladivostok and off the Korea Peninsula, respectively, and they converge while blowing over the Sea of Japan. A wind shadow, where the wind speed is less than about 9 m/s, is seen in the downwind of the mountains, extending more than 200 km. Numerical experiments using a three-dimensional local circulation model were performed to investigate the formation mechanisms of the outbreak-wind deformation. The results show that the simulated winds agree well with the NSCAT observed winds.