The Morphology of the Subtropical Anticyclone

[摘要] In order to study the morphology of the subtropical anticyclone, the monthly mean patterns in August were analyzed in the layers from the troposphere up to the lower stratosphere. From the thickness distribution along 30°N at upper isobaric levels, it is seen that in the layers above 500mb level the southern Asia anticyclone shows a higher temperature than in the northwestern Pacific anticyclone. Also it is observed that the anticyclone over the North American Continent shows a lower temperature than the southern Asia anticyclone. The temperature field in the Atlantic anticyclone is not clear. The difference of temperature between the two anticyclones over the Asiatic and North American Continents may be attributable to the different thermal influence of the Himalays and the Rockies, because the temperature distribution may greatly depend on the shape of the large scale mountain. The development (decay) of the northwestern Pacific anticyclone on the 500mb level corresponds to weakening (intensification) of the polar low. However, the strength of the southern Asia anticyclone on the 100mb level is not related to that of either polar low at the same level or the northwestern Pacific anticyclone at lower levels. Therefore we cannot consider that the northwestern Pacific anticyclone at the surface level is linked vertically with the southern Asia anticyclone.* It is speculated that the axis of the northwestern Pacific anticyclone tilts westward with altitude and connects with a separate anticyclone or an anticyclonic cell appearing off the east coast of the Continent of Eurasia. Also the Atlantic anticyclone at the surface level does not connect with the North American anticyclone on the 100mb level. The northwestern Pacific anticyclone and the Atlantic anticyclone predominate in lower layers than in the mid-troposphere, but they are different in intensity. The southern Asia anticyclone becomes stronger than the North American anticyclone in the layers between the 300mb and 100mb levels.

[学科分类] 大气科学