中国北方春季沙尘暴频数与北半球500hPa高度场的SVD分析

SVD Analysis between Northern Hemisphere 500 hPa Heights and Spring Duststorms over Northern China

选取1957—2000年中国北方地区春季沙尘暴发生次数资料和北半球500hPa秋、冬、春季的平均高度场资料,对沙尘暴和高度场作SVD分析。结果表明,我国北方春季沙尘暴次数各地具有比较一致的变化趋势,表明可能与大尺度气候背景的变化有联系。变化的最敏感区域为内蒙古中西部地区、新疆西部、青海西部和东北地区。我国北方春季沙尘暴发生次数与同期及前期500hPa高度场有较好的相关关系,前期环流形势对春季沙尘暴频数有一定的指示和预测意义,冬季环流场尤其具有预报指示意义,因为前一年冬季北大西洋涛动对我国春季北方沙尘暴发生次数有影响。

Relationship between spring duststorms over northern China and 500 hPa heights at Northern Hemisphere in autumn, winter, and spring during period of 1957-2000 are studied by applying Singular Value Decomposition (SVD) analysis. The results reveal that variability of spring duststorms over northern China are generally consistent from place to place. The most obvious change are found in west-central Inner Mongolia, western Xinjiang, northeast and western Qinghai. The patterns of 500 hPa heights in Northern Hemisphere not only control the duststorms over northern China in the same spring but also can be used as prediction signal. Especially in winter, the anomalous height implies a clear pattern as a predictant for spring duststorms. North Atlantic Ocean Oscillation in the winter has impact on occurrence of duststorms in the coming spring.