西藏地区雷暴的卫星云图特征研究

Characteristic Analysis of Satellite Images of Thunderstorm in Tibet

  • 摘要: 利用2006~2008年FY2-C卫星资料和西藏自治区雷暴记录资料,采用通道差异及云指数法对西藏地区雷暴在卫星云图上的特征进行了分析研究。结果表明,雷暴开始时刻,拉萨、日喀则、当雄卫星通道差异和云指数特征明显,红外-分裂窗亮温差值为-5~5℃、红外-水汽亮温差值为-10~10℃和FYCDI云指数为-0.11~0.28K,能较好指示西藏雷暴的开始。从初始时刻至成熟强盛阶段,雷暴的红外和水汽亮温均表现出强烈的降温,其中,雷暴开始时红外和水汽亮温下降约15℃左右,并于1~2小时后达-70℃左右的最低值,达雷暴强盛阶段;成熟阶段雷暴的红外-水汽亮温差值为0~-5℃,FYC_TS值为0左右。

     

    Abstract: Based on the FY2-C satellite and thunderstorms data from 2006 to 2008, thunderstorm’s characteristics were analyzed by channel differencing and cloud index methods in Tibet.The research results show that thunderstorms characteristic is obvious as a indicator in Lasa、Shigatse and Dangxiong.Concretely, TBB difference between IR1 and IR2 is from-5℃ to 5℃, and is from-10℃ to 10℃ between IR1 and IR3. FYCDI is from-0.11 to 0.28K. There is a distinct intensive reduction from the beginning to mature phase of thunderstorm in IR1 and IR3. Their TBB goes down 15℃, and to-70℃ within 1~2 hours. As the TBB difference between IR1 and IR2, most of them are from 0 to-5℃, and FYC_TS is close to 0 at the mature stage.

     

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