为探究复杂地形下积雪对气象条件的响应，利用2001年9月至2020年8月黄河源区MODIS（Mod‐erate Resolution lmaging Spectroradiometer）积雪覆盖时间序列产品（MOD10A2）和气温与降水量逐日观测资料，结合数字高程模型（Digital Elevation Model，DEM）数据，以积雪频率和积雪覆盖率为监测指标，分析黄河源区积雪覆盖时空变化特征及其与主要气象要素的关系。结果表明：（1）黄河源区积雪主要出现在10月至次年5月，海拔越高积雪覆盖率越大、持续时间越长，积雪主要分布在高山区。3500 m高度及以下区域积雪积累过程呈“U”字型，峰值在冬季，而 3500 m高度以上区域则过渡为倒“W”字型，且两波峰间距随海拔升高逐渐收窄，最大峰值由春季转为秋季。（2）积累期，黄河源区北坡和偏北坡的积雪覆盖率高于南坡和偏南坡，东北坡最大、南坡最小；各坡向积雪倒“W”字型积累过程特征相似且同步，峰值和次峰值分别在10月末、4月初，坡向对积雪分布的影响相较于高程弱。（3）在暖湿化气候背景下，2001年以来黄河源区积累期积雪覆盖率整体呈增加趋势，全区每10年增加约5. 6%，4000 m以上高度尤其显著，而春季及冬季4000~5000 m高度积雪面积的显著增加对积累期积雪覆盖率增大有重要贡献。（4）黄河源区各高度带积累期积雪覆盖率随气温下降和降水增加，先增后减，高度带越高拟合度越好。2001年以来积累期各季降水一致增加尤其春季高海拔区降水的显著增加是促使积雪覆盖率增大的关键因素，高海拔带积雪对降水量依赖性更强。

In order to explore the response of snow cover to climate conditions under the complex topography， based on composite snow cover products on eight days of MOD10A2，daily temperature and precipitation from September 2001 to August 2020 and digital elevation model（DEM）in the Yellow-River source region，the snow cover frequency and percentage was used as an index to study the spatio-temporal variation characteristic of snow cover and their relations with major meteorological elements. The results are as follows：（1）Snow was mainly appeared from October to next May in the Yellow-River resource region，and the higher altitude，the greater snow cover percentage and the longer duration. Snow mainly distributed in high mountainous areas. The yearly accumulative process of snow showed a U-shaped at the altitude of 3500 m and below，the peak appeared in win‐ ter，while that transited to inverted W-shaped above the altitude of 3500 m，and the gap between two peaks grad‐ ually reduced with the rising of altitude，the appearing time of the maximum peak shifted from spring to autumn. （2）The snow cover percentages on the northern and northerly slopes were more than that on the southern and southerly slopes during the accumulative period，among the maximum was on the northeastern slope，and the minimum was on the southern slope，but the yearly variation characteristics with inverted W-shaped were similar and synchronous on each slope，the maximum and secondary peaks appeared at the end of October and the early of April，respectively.（3）Under the background of warming and humidification，the snow cover percentage dur‐ ing the accumulative period exhibited an overall increasing trend with a rate of about 5. 6% per 10-year in the Yel‐ low-River resource since 2001，especially at heights above 4000 m. The significant increase of snow cover area in spring and winter at heights 4000~5000 m contributed greatly to the increase of snow cover percentage during the accumulative period.（4）The average snow cover percentage first increased and then decreased with the de‐ cline of temperature and the increase of precipitation during the cumulative period in each altitude zone of the Yellow-River source，and the higher the altitude，the higher the fitting goodness between the two. The consistent increase of precipitation was the key factor contributing to the increase of snow cover percentage in each season of accumulative period since 2001，especially the significant increase of precipitation at high altitude areas in spring. Snow was more dependent on precipitation at high altitude areas.