On the Analysis of the Typhoon Kitty

Abstract

In order to study the three-dimensional structure of typhoons, we analysed the typhoon Kitty. At first we studied it by drawing cross-sections (in both the N-S and E-W directions across Japan) of isotherms, isentropic surfaces, and the curves of pressure variation and pressure isopleths at several places. Next we examined the distribution of areas of relatively higher and lower pressures and temperatures in the region of the typhoon. Lastly we classified the tropopause into the types A, B, C, D (A: no singular points above the tropopause; B: singular points above the tropopause; C: the topopause is distinct, but other singular points are not clearly remarked owing to the lack of data; D: even the tropopause itself indistinct owing to the lack of data) and examined the distributions of these types and areas of relatively higher and lower tropopauses.
The results obtained are:
(a) 1. A region of strikingly higher temperature (corresponding to higher pressure) is recognized in the upper levels (14_??_16km) in front of the typhoon Kitty, and it moves with the typhoon. We think that this is caused by the circulation of the typhoon
2. The axis of the minimum pressure inclines to the SW direction, and the axis of the secondary minimum pressure to the NE direction.
(b) 1. The distribution of pressure at 3km and 6km, 9km and 12km, 15km and 18km respectively resemble each other in their shape. Consequently the heights where the variation of pressure distribution occurs exist between 6km and 9km, and between 12km and 15km, respectively.
2. At the center of the typhoon, the pressure is minimum up to the height 6km, and at 9km the region of minimum pressure seems to shift to the SW direction. At 15km the neighbourhood of the typhoon center becomes a high pressure area except the region in front of it, and at 18km the pressure in this region becomes also high.
3. At 9km it seems that the areas of H and L are distributed alternately.
4. At the position of the typhoon center, the temperature is low up to 3km (perhaps by the influence of rain), and at 6km the warm region around the center is isolated, and in the NE direction of the center an isolated warm region also exists. At 9km these two isolated warm regions connect with each other. At 18km the area of low pressure in front of the center becomes cold again.
5. The region of minimum pressure behind the center is warm up to 6km, and from 9km to 15km it is cold, and it becomes again warm at 18km.
6. If we compare the temperature distributions at 9km, 12km, 15km with the pressure distributions at 12km, 15km, 18km respectively, we see H and L correspond to W and C respectively. Therefore we conclude that the distribution of temperature in the region of the typhoon is dynamical.
(c) 1. In the neighbourhood of the center of the typhoon, the tropopause is high and warm, and it belongs to A-type (with no singular points). This means that a strong descending current exists up to upper levels and its magnitude decreases with the height. This mechanism concerning the tropopause is strongly different from that for cyclones in middle latitudes.
2. The tropopauses of the minimum. pressure area behind the typhoon center and of the secondary minimum pressure area in front of it are low and cold, and belong to Btype (with singular points). It means that in these regions a strong ascending current exists up to upper levels and its magnitude decreases with the height. This mechanism concerning the tropopause is also strongly different from that for cyclones in middle latitudes.
3. In the decay stage of the typhoon the tropopause is of the same type as the tropopause for cyclones in middle latitudes.