An Energetic Diagnosis And Analysis Of The Heavy Rain Process Caused By Typhoon "Saomai"

An energetic diagnostic analysis for the heavy rain process caused by typhoon "Saomai" is made in this paper. It is revealed that a ridge located in Shanxi Province at that time is the mainly large-scale circulation system of No.0608 typhoon saomai. The northwest air current in front of the ridge steers the cold air from polar region continue moving southward, which favors the cold and warm air effect one another in the eastern China. Plenty of vapour and the effect between cold and warm air benefit for the form and maintenance of rain belt in this area.By using synoptic diagnostic methods, the typhoon rainfall is analyzed with NCEP objective analysis data, the conventional observational datasets. It is found that the coupling of low-level and upper-level jets is an important cause of this heavy rainfall. Analyzing multiform physical quantity shows that the variations of chief physical quantity in the process of storm are indicators to the counterparts of precipitation in a certain sense. By using the NCEP reanalyzed grid data, we carry through an analysis of energy synoptic meteorology on the storm. At first, we figure out the total energy and wet static total energy of different time and levels. Then we can get average energy of the air column and the energy difference between different time and levels. The last figs are the vertical sections of energy distribution and profile charts of vertical energy for a single grid, and so on. These charts indicate: (1)The area of heavy precipitation has a good corresponding relation to the higher value region of upper level energy, the average total energy of air column and the anomaly of wet static total energy on 700hPa;(2)Before the rainstorm, the total energy and wet static total energy prominently increase, while after the rain, the energy value decrease sharply. (3)The energy precipitation section diffuses from the area of higher values to lower region. (4)Before and in the course of rainstorm, the energy of the precipitation region is higher than the outside.