In recent 40 years in northern china the space - time abnormity characteristics and its climatic formation cause of sand - dust storm days number change were analyzed utilizing eof and circumfluence synthesis statistic method 摘要利用eof和环流合成统计方法，分析了我国北方近40年来沙尘暴日数变化的时空异常特征及其气候成因。
