中国积雪时空演变特征及其与海气环流因子的时序关联性

积雪时空变化作为表征增暖背景下冰冻圈的重要指标之一,在全球气候变化科学研究中具有重要作用。采用1961—2016年中国545个气象观测站的积雪日数、积雪深度日值数据和3个海气环流因子,通过多种统计方法,诊断中国积雪的时空演变特征及积雪与海气环流因子的时频相关性。结果表明:(1)1961—2016年中国积雪日数和深度在波动中呈缓慢增加趋势,且具有明显的年代分段变化特征。中国积雪日数和深度均具有30a和50a的周期振荡特征,其中积雪深度在1969年发生突变。(2)1961—2016年中国气候态积雪日数和深度具有明显的南低北高的空间分异特征,尤其是东北、内蒙古东部和新疆北部的积雪较多分布。中国积雪多寡具有明显的年代和区域分异特征。(3)在变化趋势上,1961—2016年中国积雪日数在东北和内蒙古东部趋于增多;而积雪深度除上述区域外,在华北、西北和江淮东部也趋于增多。在波动特征上,中国积雪日数和深度在华南南部、云南和四川东部波动较大,其它地区波动相对较小。(4)与海气因子时频关联性上,中国积雪与不同海气因子关联性不同,且与同一因子在不同时段的关联性也有一定差异。

Temporal and spatial evolution characteristics of snow cover in China and their temporal relevancies with ocean atmospheric circulation factors

Temporal and spatial variations of snow cover，as one of the important indicators of the cryosphere under warming background，play an important role in global climate change system science research． Based on the days with snow cover and the daily data of snow depth from 1961 to 2016 from 545 meteorological stations in China and three ocean atmospheric circulation factors，the temporal and spatial evolution characteristics of snow cover in China and their time frequency relevancies with the ocean atmospheric circulation factors are diagnosed through several statistical methods． The result shows that ( 1) both the days with snow cover and the snow depth from 1961 to 2016 in China exhibit slowly increasing trends in fluctuation with obvious characteristics of yearly variation． Both the days with snow cover and the snow depth in China have the characteristics of periodic oscillations of 30 and 50 years，in which the mutation of snow depth occurs in 1969; ( 2) the days with snow cover and the snow depth from 1961 to 2016 in China have obvious spatial differentiation characteristics of low in the south and high in the north，especially the snow covers are more distributed in the Northeast China，the Eastern Inner Mongolia and the Northern Xinjiang． More or less snow covers in China have obvious yearly and regional differentiation characteristics; ( 3) in the aspect of changing trend，the days with snow cover in China tend to be increased in the Northeast China and the Eastern Inner Mongolia，while the snow depth tends to be increased as well in the North China，the Northwest China and the Eastern Jiang-Huai region except the regions mentioned above; in the aspect of fluctuation characteristics，the days with snow cover and the snow depth in China are largely fluctuated in the south of the Southern China，Yunnan and the Eastern Sichuan，while the fluctuations in the other regions are less; ( 4) in the aspect of the time-frequency relevancy with the ocean atmospheric circulation factors，the time-frequency relevancy of the snow cover in China is not only different with different ocean atmospheric circulation factors，but its relevancy is also different with the same factor at different period of time．