锡林郭勒积雪日数时空分布规律研究

Spatio-temporal characteristics of snow cover days in Xilin Gol

利用1971—2015年锡林郭勒地区15个气象观测站近45 a的逐日积雪日数资料,采用滑动T检验、Mann-Kendall检验、小波分析和EOF方法对研究区的积雪日数时空变化特征进行分析。结果表明:研究期内积雪日数在1996年发生了一次由多到少的突变,且日数变化存在7 a的主周期和11 a、22 a的副周期。积雪月际变化呈单峰型的分布特征,多雪期主要集中在12～2月,少雪期分布在10月份和4月份;研究区空间分布差异性显著,总体呈东多西少、南多北少的分布格局,区内大部地区属于稳定积雪区。对积雪日数及其影响因子进行聚类分析,将研究区划分为4种类型,分别为降雪量偏少—积雪日数偏高区、降雪量—积雪日数一致偏高区、降雪量—积雪日数中值区、降雪量—积雪日数一致偏少区。该区有3种异常分布型:第一模态为全区一致偏多(少)型;第二模态为北多(少)南少(多)型;第三模态为中西部多(少),东南部少(多)型。

Based on the data from 15 meteorological stations covering the period from 1971 to 2015, this paper analyzed the spatio-temporal characteristics of snow cover days in Xilin Gol League, Inner Mongolia, China, by running t-test, Mann-Kendall test, wavelet analysis and empirical orthogonal function （EOF） method. The results are cap- tured as follows：there was a sudden change in the snow cover days from many to less in 1996 and there was a quasi- periods of 7 years for this type of change. The monthly average of snow cover days showed a single peak type of dis- tribution, with the months of December, January and February forming the peak which accounted for 69% of the to- tal snow days while the sum of those in October and April taking up only 6%. The spatial distribution displayed a significant variation with larger numbers in the south and east and smaller numbers in the north and west in the re- gion from an overall perspective. Except Erenhot and Sonid Right Banner, the snow cover days in most areas of Xilin Gol exceeded 90 days and therefore Xilin Gol is a region of stable snowing. The study region was divided into four categories based on the cluster analysis using the snow cover days and its influencing factors： the area with less snowfall but a big snow cover days, such as East Wuzhumuqinqi and Wulagai; cordance with the snow cover days and both are on the high side, such as Zh the area where the snowfall is in ac- engxiangbai Banner and Taibus Ban- ner; the area where the snowfall and snow cover days are in the median, such as Zhenglan Banner and Xianghuang Banner; the area where the snowfall is in accordance with the snow cover days and both are on the low side, such as Erenhot and Sonid Right Banner. From EOF method, there were three major spatial patterns in the region ： （ 1 ） consistently more or fewer than the average in an area; （2） a seesaw between south and north; （3） a seesaw between central west and southeast.