The linear regression and horizontally stepwise correction are conducted on the observational data from AMSU-A L1 B of NOAA polar orbit satellite to invert a 40-layers(from 1,000 h Pa to 0.1 h Pa) dataset of atmospheric temperature with a horizontal resolution of 0.5°×0.5° after the correction of satellite antenna pattern and limb adjustment. Case study shows that the inversion data of temperature can reveal the detail structure of warm core in tropical cyclone. We choose two categories of tropical depressions(TDs) over the South China Sea, including the non-developing TDs and developing TDs. Both of them are developed downward from the middle and upper level to the lower level. Comparison between the evolutions of warm core in the two categories of TDs indicates that the warm core is developed downward from the middle and upper troposphere to the sea surface in all the downward-developing TDs. The difference is that in the group of further developing TDs, the warm core in the upper troposphere is intensified suddenly when it is extending to the sea surface. The warm core in the upper and lower troposphere is strengthened in a meantime. But the similar feature is not observed in the non-developing TDs. Then it may be helpful to judge the TD development by monitoring the change in its warm-core structure.
Observation from automatic weather stations, radars and TRMM satellites are employed to investigate the precipitation distribution of tropical cyclone(TC) Koppu(0915) that made landfall on Guangdong province in 2009.The results show that the precipitation of landfall TC Koppu is featured by significant asymmetry and mesoscale structure, and occurs mainly to the left of its moving path. By examining the sea surface temperature(SST), water vapor flux, Q vector, vertical wind shear of environment etc., it is found out that the distribution of SST, water vapor convergence, low-level convective ascending and vertical wind shear facilitates the TC precipitation to take place to the left of the TC moving path. The mesoscale structure separated by Barnes band-pass filter presents that the precipitation of landfall KOPPU has some organized mesoscale spiral structures, which is around the TC center and composed of the form of belts or blocks. The heavy local rainfall of landfall TC Koppu is primarily associated with the rainfall due to mesoscale spiral structure.
