On the High Tropospheric Conditions of Wind and Temperature over Japan during June 1953

[摘要] First, main characteristics of mean conditions of the upper troposphere during June 1953 are as follows:1) Mean jet of 140°E meridian is situated at 37°N near 12km (50m sec-1). On 12km level chart the mean jet passes through the northern part of Korean Strait and 37°N 140°E.2) Along 140°E meridian, just under the mean jet, mean horizontal temperature gradient is relatively strong between 500 mb and 300 mb.3) On 500 mb chart, northern part of the mean jet axis (of 12km) is dry (relative humidity 50%) and southern part is wet (60_??_70%).Second, main characteristics of the meridional cross sections through Japan during 6_??_7 June, 1953 are as follows:4) Polar front (Baiu-front) is rather shallow over Honshu and increases its inclinatiom over Hokkaido. Polar-front jet is situated at 45°N near 250 mb.5) Subtropical jet is situated at 40°N near 150_??_200 mb. Under this jet there exists a frontal zone between temperate air and tropical air. This frontal zone might be called as a subtropical front.6) Distinct polar-front tropopause (in Palmén's sense) is observed associated with the polar-front jet and the subtropical jet.7) Tropical cyclone Judy (5302) has its maximum wind speed at 450 mb level, at 12 Japanese Standard Time, 7 June.

[学科分类] 大气科学