1979-2018年澜沧江乌弄龙流域积雪时空变化及其影响因素

Spatiotemporal Variations of Snow Cover and Its Influencing Factors in The Wunonglong Basin From 1979 to 2018

积雪是地表特征的重要参数,其对辐射收支、能量平衡及天气和气候变化有重要影响。基于1979-2018年积雪深度卫星数据及同期的格点型降水和气温观测资料,分析了澜沧江上游乌弄龙流域积雪的时空变化特征及其与气候因子的关系。采用回归分析法分析积雪及气候因子随时间的变化趋势和幅度。利用相关分析法研究降水、气温对积雪的影响及其空间规律。结果表明:流域内降水量、气温和雪深空间分布不均,西北部和东南部积雪深度较大;年降水量和年均气温呈逐年上升趋势,流域各部分上升速度存在明显差异,年均雪深表现为整体下降趋势且主要集中在流域西北部和中部区域;积雪深度与降水量多为正相关,与气温多为负相关,在研究区上游和下游表现的相关性较强。

Snow cover is an important parameter of land surface features,which has significant impacts on radiation balance,energy budget,weather and climate change.Based on satellite data of snow depth from 1979 to 2018 and corresponding observed data of gridded precipitation and temperature,the spatiotemporal variations of snow cover in the Wunonglong Basin,upstream of the Lancang River,as well as its relationship with climate factors were analyzed.Regression analysis was used to explore the temporal trends and amplitudes of snow cover and climate factors.Correlation analysis was conducted to investigate the spatial patterns of precipitation and temperature impacts on snow cover.The results showed that precipitation,temperature,and snow depth distribution were uneven in the basin,with larger snow depth in the northwest and southeast.Annual precipitation and mean temperature exhibited an increasing trend,with a significant difference in the rising speed among different regions in the basin.Overall,the annual snow depth showed a decreasing trend mainly concentrated in the northwest and central regions of the basin.Snow depth was positively correlated with precipitation and negatively correlated with temperature,with stronger correlations in upstream and downstream areas of the study area.