西藏地区雷暴与大气热源关系研究

利用1979～2008年NCEP/NCAR全球再分析月平均资料和雷暴记录资料, 运用相关分析和合成分析等方法分别对西藏地区大气热源和雷暴日数的关系以及热源强弱不同时期雷暴日数变化特征进行了分析。结果表明, 大气热源与雷暴日数存在着明显的正相关关系, 月相关系数高达0.86。在雷暴高发区的那曲东部、拉萨、日喀则中部、山南地区东北部和林芝地区西北部, 相关系数均超过了0.4。进一步分析表明, 当大气热源强值年时, 整个日喀则地区、拉萨地区、山南地区、那曲中西部和东部地区以及昌都地区中西部, 雷暴日数是偏多的。当大气热源偏弱时, 雷暴日数在日喀则中部地区减少最为明显, 其次在日喀则南木林县东北部和林芝西北部地区。

Relationships between Thunderstorms and Atmospheric Heat Source in Tibet

Based on global NCEP/NCAR reanalysis data and thunderstorm data from 1979 to 2008, the relation- ships between the atmospheric heat source and the number of thunderstorm days are analyzed, as well as the variations in the number of thunderstorm days with different heat source intensities. The results indicate that the intensity of the atmospheric heat source is positively correlated with the number of thunderstorm days, with correlation coefficients as high as 0.86. Further, the correlation coefficients exceed 0.4 in eastern Nagqu, Lhasa, central Shigatse, northeastern Shannan, and northwestern Nyingchi, where thunderstorms are the most dominant activity. Further analysis shows that more thunderstorm days than the average occur in Shigatse, Lhasa, Shannan, most parts of Nagqu, and the midwestern region of Qamdo when the atmospheric heat source is stronger. In contrast, in years with a weaker heat source, the number of thunderstorm days is reduced in central Shigatse, Namling, and northwestern Nyingchi.