Seasonal snow cover in mountainous areas is a key source of water for downstream regions. The snow cover area (SCA) in the Northern Hemisphere has significantly decreased during the past decades in response to global warming. Therefore, it is necessary to investigate the primary factors controlling the spatiotemporal variabilities in the SCA in high altitude regions. In this study, based on remote sensing data of SCA, temperature, and precipitation in the Yarlung Zangbo River basin, Pearson's correlation analysis was used to identify the relative importance of temperature and precipitation on the SCA variability with altitude. The results showed that temperature played a more dominant role for the SCA than precipitation at all elevation during the period 2001–2017; three threshold altitudes at high, moderate, and low elevation were identified, and these threshold altitudes are dynamic and vary with time; the threshold altitude at high elevation was 5,925 ± 125 m, below which temperature (precipitation) was negatively (positively) correlated and above which temperature (precipitation) was positively (negatively) correlated with the SCA; the threshold altitude at moderate elevation was 3,200 ± 300 m, below which temperature (precipitation) was positively (negatively) correlated and above which temperature (precipitation) was negatively (positively) correlated with the SCA; the threshold altitude in low elevation regions was 2,100 ± 200 m. This study sheds light on the dominant climatic control factors on the variability in SCA in high altitude regions. These results have major implications for SCA and water resources availability under future climate change.

中文翻译：

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温度和降水对雅鲁藏布江流域积雪变化的垂直影响

山区的季节性积雪是下游地区的主要水源。在过去的几十年中，由于全球变暖，北半球的积雪面积（SCA）大大减少。因此，有必要研究控制高海拔地区SCA中时空变化的主要因素。在这项研究中，根据雅鲁藏布江流域SCA，温度和降水的遥感数据，使用Pearson相关分析确定温度和降水对SCA随高度变化的相对重要性。结果显示，在2001-2017年期间，温度对SCA的影响比降水在所有海拔的影响更大；确定了高，中和低海拔的三个阈值高度，这些阈值高度是动态的，并随时间而变化；高海拔的阈值海拔高度为5,925±125 m，低于该高度时，温度（降水）与SCA呈负（正）相关，高于该温度时（降水）与SCA呈正（负）相关；中海拔的阈值海拔高度为3200±300 m，低于该高度时，温度（降水）与SCA正相关（负），高于该温度时（降水）与SCA负相关（正）。低海拔地区的阈值高度为2,100±200 m。这项研究揭示了高海拔地区SCA变异的主要气候控制因素。这些结果对未来气候变化下的SCA和水资源可利用性具有重大影响。