高原东部凝结潜热及其对北半球500hPa高度场和我国汛期降水的影响

Latent Heat Series over the East Part of QXP in Rainy Season and Its Impact on 500hPa Height Fields of Northern Hemisphere and Precipitation in China Flood Season

利用1961—2005年青藏高原东部雨季凝结潜热序列进一步分析其气候特征及其对后期北半球大气环流和中国汛期降水的影响。结果表明，青藏高原东部雨季各月的凝结潜热均有所增加，其年际变化的差异也较大，其中5月最大，6～7月较稳定，极大年份均出现在气候明显变暖的近10年，极小年份多数出现在气候相对较冷的时期。青藏高原东部凝结潜热具有一定的持续影响力，当其潜热增强时，可引起北半球同纬度带的位势高度场偏低，特别是西太平洋副热带高压偏弱，位置偏南，进而使我国长江流域汛期降水偏多，西北区东部、华北、东北区南部及华南降水偏少。

Using the latent heat series in rainy seasons over the east part of Qinghai-Xizang Plateau （QXP） in the period from 1961 to 2005, its climatic characteristics are analyzed and then its influences to atmospheric circulation of Northern Hemisphere and precipitation of China are studied. Results show： （1） the setting latent heat of every month has a certain increase over the eastern part of Qinghai-Xizang Plateau in rainy season. The difference of its interannual variation is also clear, and its difference is the biggest （steady） in May （June and July）. （2） The maximum （minimum） year appears in the period of warmer （colder）. （3） It has at least one month sustained influence power, and when it is enhance, which can cause the same latitude＇s geopotential height field of Northern Hemisphere lower. Specially, west Pacific ocean subtropical high pressure is weaker, and its position declines toward the south, then causes precipitation in flood season of Yangtze River valley is northwest eastern part and northeast south more. ern part But the precipitation of South China, North China, of China are less.