INVERSION OF TEMPERATURE FROM AMSU-A AND ITS APPLICATION ON WARM-CORE OF TROPICAL DEPRESSION OVER THE SOUTH CHINA SEA

The linear regression and horizontally stepwise correction are conducted on the observational data from AMSU-A L1B of NOAA polar orbit satellite to invert a 40-layers (from 1,000 hPa to 0.1 hPa) 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.