The influence of climate change on regional-scale precipitation is becoming undeniable, and can lead to increased flood and drought risks in some regions. The study assessed the potential effect of global warming of 1.5 °C and 2 °C on total precipitation and snowfall in the Upper Yangtze River Basin (UYRB) based on General Circulation Models (GCMs). Seven total precipitation and six snowfall indices were employed in this analysis. The results show that the annual precipitation (PA) in the UYRB will increase by approximately 4.5–5% and 9–13% per 1.0 °C under the 1.5 °C and 2 °C warming, respectively. Spatially, the PA is shown to increase across the northern part of the basin, but decrease in the southern part. Relative to the baseline period (1986–2005), the frequency of trace and moderate precipitation days shows a decreasing trend, while that of heavy and intense precipitation days will increase under both 1.5 °C and 2 °C warming scenarios. Moreover, it varies among significance levels of trace, light, moderate, heavy and intense precipitation frequency under 1.5 °C and 2 °C warming for different Representative Concentration Pathways (RCPs). Unlike overall total precipitation, the annual snowfall (ASF) will decrease by approximately 2.5–8% per 1.0 °C under the 1.5 °C warming, and the 2–4% per 1.0 °C under the 2 °C warming. The ASF exhibits a decreasing trend in most of the UYRB except for the far northern part under all global warming scenarios. The date of first snowfall is modeled to be delayed and that of last snowfall will advance, which will lead to the decrease of snowfall days by about 15–20 days under different warming scenarios. In a warming world, total precipitation in the UYRB will increase and snowfall will decrease, which may increase the risk of flood in the future, and more attention should be paid.

中文翻译：

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1.5°C和2°C全球变暖情景下长江上游流域总降水量和降雪量的差异

气候变化对区域尺度降水的影响越来越不可否认，并可能导致部分地区水旱灾害风险增加。该研究基于大气环流模型 (GCM) 评估了全球变暖 1.5 °C 和 2 °C 对长江上游流域 (UYRB) 总降水量和降雪量的潜在影响。在该分析中使用了七个总降水量和六个降雪指数。结果表明，在升温1.5°C和2°C的情况下，UYRB的年降水量（PA）每增加1.0°C将分别增加约4.5-5%和9-13%。在空间上，PA 在盆地北部增加，但在南部减少。相对于基线期（1986-2005），微量和中等降水日数出现频率呈下降趋势，而在 1.5 °C 和 2 °C 升温情景下，强降水日数都会增加。此外，在 1.5 °C 和 2 °C 升温下，不同代表性浓度路径 (RCP) 的微量、轻、中、重和强降水频率的显着性水平不同。与总降水量不同，年降雪量 (ASF) 在升温 1.5 °C 下每 1.0 °C 减少约 2.5-8%，在升温 2 °C 下每 1.0 °C 减少 2-4%。在所有全球变暖情景下，除远北地区外，大部分 UYRB 的 ASF 均呈现下降趋势。模拟首场降雪日期推迟，末场降雪日期提前，导致不同增温情景下降雪日数减少约15-20天。在一个变暖的世界里，