黄河流域近40年气候变化的时空特征

黄河流域是我国主要的气候敏感区之一,气候变化对其生态环境演变与经济社会发展有显著影响。本文利用欧洲中期天气预报中心ERA5再分析资料分析了黄河流域过去40年的温度、降水、水汽通量散度、蒸散和荒漠化风险等的演变特征,结果发现:1979—2019年黄河流域四季均呈现明显增温趋势,其中春季增温最为明显;季节性降水的变化差异显著,春季和夏季降水呈现下降趋势,秋季降水增加;黄河流域空中水汽以辐合为主,过去40年黄河流域上游水汽辐合年际波动最小,中游次之,下游最大;黄河流域蒸散整体呈现减少趋势,其中增加趋势集中在上游地区;黄河流域荒漠化风险整体处于中等风险以上,呈现由南向北加剧的空间分布,1982—2014年黄河流域荒漠化风险呈现下降趋势。本研究厘清了全球气候变化背景下黄河流域蒸散、水汽输送和降水等水循环过程的变化规律,能够为维护黄河流域地区生态安全、防范重大气象灾害风险提供科学依据。

Characteristics of climate change in the Yellow River basin during recent 40 years

The Yellow River basin is one of the main climate sensitive areas in China, and climate change has a significant impact on ecological environment evolution and socioeconomic development. In this paper, the evolution characteristics of temperature, precipitation, moisture flux divergence, evapotranspiration, and desertification risk in the Yellow River basin in the past 40 years are analyzed by using ERA5 reanalysis data of the European Centre for Medium Range Weather Forecast. The results show that the Yellow River Basin has a significant warming trend in the four seasons from 1979 to 2019,with the most obvious in spring. Different with temperature, the seasonal precipitation showed a decreasing trend in spring and summer, and increasing trend in autumn. In the past 40 years, annual fluctuation of water vapor convergence in the upper reaches of the Yellow River basin is the smallest, followed by the middle reaches, and the lower reaches. Meanwhile, the evapotranspiration in the Yellow River Basin showed a decreasing trend, with little increasing trend in the upper reaches. The desertification risk of the Yellow River Basin is above the medium level as a whole, with a spatial distribution increasing from south to north, and decreasing trend from 1982 to 2014. In the context of global climate change, the change rules of the water cycle such as evapotranspiration, vapor transport and precipitation in the Yellow River basin are clarified, which can provide scientific basis for maintaining the ecological security of the Yellow River basin and preventing the risk of major meteorological disasters.