近40年北疆年积雪日数变化的CEOF分析

A CEOF Analysis on Variation about Yearly Snow Days in Northern Xinjiang in Recent 40 Years

通过1961—2001年间北疆年积雪日数的CEOF分析,研究了40年来北疆年降雪日数的时空变化特点。结果表明:北疆年积雪日数场有波动特征。第一种类型为南—北一致偏多(偏少)型,空间位相相近,并有6.4年和3.6年的周期。第二种类型为西南—东北一致偏多(偏少)型,空间位相相近,并有6.4年的周期。第一复主分量的时间位相和第二复主分量的时间振幅峰值年可用于年积雪日数的预测。

By using the complex empirical orthogonal function (CEOF) analyses, the spatial and temporal distributions about yearly snow days in Northern Xinjiang in 1961\_2001 are investigated. The results show that there are two main types of the spatial distribution of snow days. In the first type, more (or less) yearly snow days appear in the north and south of Northern Xinjiang, their spatial phases are approximately the same, and there are 6.4 and 3.1 year periods. In the second type, more (or less) days of yearly snow lying appear in the southwest- northeast of Northern Xinjiang, their spatial phases are approximately the same too, and there are 6.4 year periods. Time phase for the first complex principal component and time amplitude for the second one may use forecast of days of yearly snow lying.