2002-2016年高亚洲500m MODIS逐日积雪覆盖率数据集

高亚洲是以青藏高原为主要区域的亚洲高海拔地区，是中低纬度高山积雪的重要分布区，其积雪的动态变化对水和能量平衡及区域气候具有重要的影响。由于青藏高原地区季节性积雪具有赋存时间短、雪层较薄的特点，在对水循环等问题的理解中，迫切需要日时间尺度的积雪覆盖度动态监测数据。本数据集基于空间分辨率为500 m的MODIS归一化积雪指数数据，结合地形和多种云覆盖下积雪覆盖度估算算法的优势，实现云覆盖条件下的积雪覆盖度再估算，满足高亚洲地区逐日少云（＜10％）数据产品的生产要求，构建了2002～2016年高亚洲地区MODIS逐日积雪覆盖度数据集。选取无云条件下的二值积雪产品作为参考，通过云量分布和积雪总面积的时空对比，表明该产品的时空特征和二值产品具有较好的一致性。以2013年冬季为例，当积雪覆盖度大于50％时，其相关性可达0.8628。本数据集可为高亚洲地区的积雪动态监测、气候环境、水文和能量平衡、灾害评估等研究提供逐日积雪覆盖度数据。

The High Asia region, centered on the Tibetan Plateau, is a high-altitude area in Asia and an important distribution region of mountain snow cover at mid-to-low latitudes. The dynamic changes of its snow cover exert significant impacts on water and energy balance as well as regional climate. Given that seasonal snow cover on the Tibetan Plateau features short retention duration and thin snow layers, dynamic monitoring data of snow cover fraction at daily time scales are urgently needed to advance the understanding of issues such as the water cycle. This dataset is developed based on MODIS Normalized Difference Snow Index (NDSI) data with a spatial resolution of 500 m, leveraging the advantages of topographic correction and multiple cloud-covered snow cover fraction estimation algorithms to re-estimate snow cover fraction under cloud-covered conditions. It meets the production requirements of daily cloud-reduced (cloud cover <10%) data products for the High Asia region, and a 2002–2016 MODIS daily snow cover fraction dataset for the High Asia region is thus constructed. Taking the cloud-free binary snow cover product as the reference, through spatial-temporal comparison of cloud cover distribution and total snow cover area, it is verified that the temporal and spatial characteristics of this product are in good consistency with those of the binary product. Taking the winter of 2013 as an example, the correlation coefficient can reach 0.8628 when the snow cover fraction is greater than 50%. This dataset can provide daily snow cover fraction data for research on snow cover dynamic monitoring, climate and environment, hydrological and energy balance, disaster assessment and other related studies in the High Asia region.

搜集汇总

背景与挑战

背景概述

该数据集为2002-2016年高亚洲地区500m分辨率的MODIS逐日积雪覆盖率数据，覆盖北纬26°-46°，东经62°-105°范围，采用GeoTiff格式存储。数据集通过优化算法减少了云覆盖影响，适用于积雪动态监测、气候环境和水文研究等领域。