FURTHER ANALYSES OF THE STRUCTURE OF TYPHOON NO. 7507 Ⅱ. TEMPERATURE AND MOISTURE FIELDS

This paper, the second part of further analyses of the structure of the typhoon, mainly discusses the distributions of temperature and moisture fields of typhoon No.7507.The result has shown that the typhoon developed from the warm-core disturbance.The height of maximum warming is highest (300 to 250 hPa) during the mature stage.There is a dry layer capping the typhoon during the initial stage.Once the typhoon rapidly developed, the dry layer was destroyed.A deep saturation layer eventually occurred in the central region of the typhoon.Meanwhile, the dry air from the China main continuously intruded into the outer region in the western and northwestern parts of the typhoon.
The initial eyewall of the typhoon sloped outward with increasing height, and then became nearly vertical below 12 km level.This was closely associated with convective activity.The convective instability had been mostly released during the growing stage of the typhoon and stratification rapidly tended to moist neutralization.In addition.the water vapor flux in the south of the typhoon was clearly different from that in the north, with divergence in the north and convergence in the south in the lower troposphere.The strongest convergence occurred in the boundary layer, especially near the surface of the earth.