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Based on the reanalysis data of monthly mean global SST and wind from the NCEP/NCAR and the observation data of rain seasons in 124 stations of Yunnan province from 1961 to 2006, we applied the analytical methods of correlation analysis and composite analysis and a significance testing method to two sets of samples of average differences. The goal is to investigate into the influence of the Southern Hemispheric (SH) SST on the summer precipitation in Yunnan from January to May so as to identify the key time and marine regions. Physical mechanisms are obtained by analyzing the influence of sea level wind and the key marine regions on the precipitation during Yunnan’s rain season. Results show that there is indeed significant relationship between the SST in SH and summer precipitation in Yunnan. The key areas for influencing the summer precipitation are mainly distributed in a region called “West Wind Drift” in the SH, including the Southeast Indian, southern Australia, west coast of eastern Pacific off Chile, Peru and the southwest Atlantic Magellan. Besides, the most significant marine region is the west coast of Chile and Peru (cold-current areas of the eastern Pacific). Diagnostic analysis results also showed that monsoons in the Bay of Bengal, a cross-equatorial flow in the Indian Ocean near the equator and southwest monsoon in India weaken during the warm phase of the Peruvian cold current in the eastern Pacific. Otherwise, they strengthen. 相似文献
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一次云南强对流暴雨的中尺度特征分析 总被引：2，自引：2，他引：0
利用NCEP/NCAR再分析资料及常规观测资料与雷达、卫星等非常规观测资料,综合分析了2014年6月6日云南暴雨过程的天气成因及中尺度对流系统特征。结果表明:500hPa前倾槽、700hPa切变线及地面冷锋是此次暴雨过程的天气尺度影响系统;高能高湿的对流不稳定层结、明显的垂直风向切变是强对流天气形成的有利条件;在Q矢量散度辐合区内多个β中尺度对流系统(MCS)发生发展,短时强降水主要出现在MCS移动方前沿对流活跃的云顶亮温(TBB)等值线密集区,雨强变化与TBB等值线梯度变化密切相关;多普勒雷达及地闪资料显示多个γ中尺度对流系统是强对流暴雨产生的直接影响系统,雷暴易发生于回波强度在35~45dBz、回波顶高超过10km的区域,中尺度辐合线、第二类γ中尺度辐合区附近负地闪密集区与短时强降水、雷暴天气有很好的对应关系。 相似文献
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采用NCEP/NCAR 1961—2006年的全球月平均海表温度和风场再分析资料,以及云南省汛期(6—8月)124个观测站的降水资料,运用相关分析、合成分析及两组样本平均值差异的显著性检验方法,研究前期1—5月南半球海表温度对云南汛期降水异常有影响的关键时期和关键海区,并用南半球海平面风场分析关键海区的海温异常对云南汛期降水异常影响的物理成因机制。结果表明,前期南半球海表温度与云南汛期降水相关显著,显著关键海区主要位于南半球西风漂流区的东南印度洋、澳大利亚南部、东太平洋的智利和秘鲁西海岸及西南大西洋的麦哲伦海峡。其中东太平洋秘鲁寒流区的智利和秘鲁西海岸是影响云南汛期降水最显著的关键区。诊断分析还表明,在东太平洋秘鲁寒流区的暖位相期,孟加拉湾地区的季风和赤道印度洋附近的越赤道气流及印度洋的西南季风减弱,反之则加强。 相似文献
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