Water vapor sources for Yangtze River Valley rainfall: Climatology, variability, and implications for rainfall forecasting
Water vapor sources for Yangtze River Valley rainfall: Climatology, variability, and implications for rainfall forecasting
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DOI：
10.1029/2011jd016902
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发表时间：
2012-03
影响因子：
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通讯作者：
Jiangfeng Wei;P. Dirmeyer;M. Bosilovich;R. Wu
中科院分区：
文献类型：
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作者：
Jiangfeng Wei;P. Dirmeyer;M. Bosilovich;R. Wu
[1]水汽通量的计算方法虽然能反映水汽输送的路径，但不能很好地识别水汽的源汇。本文利用现代回顾分析研究与应用（MERRA）的气象资料，采用水汽反轨迹法估算了长江流域降水的蒸发水汽来源。主要的水分来源及其相对贡献表现出很大的季节变化。来自孟加拉湾和西太平洋的水分通常在YRV湿季（4月至9月）的演变过程中和每年的湿月（8月达到峰值）之间相互补偿。主要的直接水汽来源是在YRV上，其主要的水汽输送途径是在陆地上，而不是在海洋上，但海洋在启动水汽输送方面是重要的。然而，在这些重要的陆地水分来源，地表蒸散不受土壤湿度的控制，对降雨的变化影响很小。在YRV的本地水分循环主要是一个被动的响应降雨和环流的变化。因此，YRV雨季降雨量的预测更多地取决于对大规模环流和季风的了解，而不是地表条件。
[1] The method of calculating water vapor flux can show the paths of moisture transport but cannot easily identify the sources and sinks of water vapor. In this study, we estimate the evaporative moisture sources for the Yangtze River Valley (YRV) rainfall with a water vapor back-trajectory method, using meteorological data from the Modern Era Retrospective-analysis for Research and Applications (MERRA). The major moisture sources and their relative contributions show large seasonal variations. The moisture from the Bay of Bengal and the western Pacific usually compensate each other both during the evolution of YRV wet season (April–September) and interannually for the wet months (peak in August). The major direct moisture sources are over YRV and its major moisture transport pathways over land, rather than over the ocean, but the ocean is important in initiating the moisture transfer. However, over these important land moisture sources, surface evapotranspiration is not controlled by soil wetness and has weak impact on the variability of rainfall. Local moisture recycling over YRV is mostly a passive response to rainfall and circulation changes. The prediction of YRV rainy season rainfall thus depends more on the knowledge of large-scale circulations and monsoons than land surface conditions.