伊犁地区2010~2017年暴雨过程的水汽特征分析

Analysis of Water Vapor Characteristics during the Heavy Rains in Yili Area from 2010 to 2017

利用NECP/NCAR再分析资料,总结了2010~2017年伊犁地区30次暴雨过程的水汽特征,通过分析700 hPa水汽通量及风场、水汽通量散度、比湿、大气可降水量等物理量,得出:伊犁暴雨东南部多,西部少;夏季多,春秋季少;出现暴雨时700 hPa水汽通量散度、比湿、大气可降水量等物理量指标分别为?3 ×10?5 g?m?2?s?1,6~7 g/kg,30 kg/m?2;伊犁暴雨的水汽源地有里海、黑海、红海、地中海、孟加拉湾、咸海、巴尔喀什湖、阿拉伯海,其中黑海和里海对伊犁地区暴雨水汽贡献最大。阿拉伯海、孟加拉湾作为水汽源地,大气可降水量达到60 kg/m?2,是否可作为暴雨的预报指标有待进一步验证;系统性暴雨和区域性暴雨比湿、大气可降水量等指标差别不大,而系统性暴雨水汽辐合强度明显高于区域性暴雨。

Based on the NECP/NCAR reanalysis data, the water vapor characteristics of 30 heavy rains processes in Yili area from 2010 to 2017 are summarized. 700 hPa water vapor flux and wind field, divergence of vapor flux, specific humidity, atmospheric precipitation were analyzed. It is concluded that the heavy rains in yili area are more in the south and east and less in the west, that heavy rains occur more in summer, less in spring and autumn. In the case of heavy rains, the physical indexes of divergence of vapor flux of 700 hPa are ?3 ×10?5g?m?2?s?1, specific humidity of 700 hPa are 6 - 7g/kg, atmospheric precipitation of 700 hPa are 30 kg/m?2. Water vapor in the heavy rains in Yili originates from the Caspian Sea, Black Sea, Red Sea, Mediterranean Sea, bay of Bengal, Aral Sea, Balkashi Lake and Arabian Sea, the Black Sea and Caspian Sea contribute the most. When the Arabian Sea and the Bay of Bengal are the water vapor sources, whether the atmospheric precipitation up to 60 kg/m?2 can be used as the prediction index of heavy rains needs to be further verified. There is little difference between systematic heavy rains and regional heavy rains in terms of specific humidity and atmospheric precipitation, but the moisture convergence intensity of systematic heavy rains is obviously higher than that of regional heavy rains.