青藏高原雪水比例时空变化特征

Spatiotemporal variation characteristics of snowfall-precipitation ratio on the Tibetan Plateau

  • 摘要: 为厘清青藏高原地区不同相态降水及其变化规律, 本文基于第三极地区长时间序列(1979—2020年)高分辨率(1/30°, 日)地面气象要素驱动数据集, 采用基于表面高程和气象条件的雨雪识别方法, 识别了青藏高原地区的降雨和降雪, 分析了青藏高原雪水比例(SPR)的分布特征和时空演变规律。结果表明: ① SPR空间分布差异显著, 西高东低; ② SPR整体呈下降趋势, 平均以1.11%/(10 a)的速率显著降低; ③冷、暖季均呈现降雨增加、降雪减少、SPR降低趋势, 但暖季的变化速率和显著性高于冷季;④高原东西部降雪量在冷、暖季相当, 高原中部以暖季降雪为主,高原暖季降雨量约占全年的90%,高原大部分地区暖季降雪占全年降雪的比例呈下降趋势(-0.29%/(10 a))。研究结果有望为区域气候变化和水科学研究提供科学依据。

     

    Abstract: This study investigates the variations in precipitation phases on the Tibetan Plateau (TP) from 1979 to 2020. Utilizing the Third Pole region′s high-resolution (1/30°, daily) surface meteorological data (TPMFD) and a method based on elevation and meteorological conditions, we analyzed the snowfall-precipitation ratio (SPR) spatiotemporal characteristics on the TP. Key findings include: ① Significant spatial differences in SPR, with higher values in the west and lower in the east. ② An overall downward trend in SPR, decreasing at an average rate of 1.11% per decade (p < 0.001). ③ Both cold and warm seasons exhibit increases in rainfall and decreases in snowfall and SPR. However, the rates of change are more pronounced in the warm season. ④ Snowfall is comparable in the cold and warm seasons in the east and west of the plateau. In contrast, the central plateau experiences predominant snowfall during the warm season. About 90% of the annual rainfall occurs in the warm season, and the proportion of warm season snowfall to annual snowfall is decreasing (-0.29% per decade) in most plateau regions. These findings provide valuable insights for regional climate change and water science research.

     

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