摘要:
本文运用NCEP/NCAR再分析数据，计算分析了海河流域整层大气水汽含量即可降水量、纬向输送水汽通量、经向输送水汽通量以及流域的四个边界水汽通量的季节变化和年代际变化特征。结果表明：近50年来海河流域整层大气可降水量呈减小趋势，并于2009年降到近50年的最低值，夏季大气可降水量高于其他季节；经向和纬向水汽输送通量年际变化均呈减小趋势，但纬向水汽输送方向全年由西向东，而经向水汽输送方向冬半年为由北向南，夏半年由南向北；海河流域的水汽收支代际变化均为输入，但总体上呈下降趋势，且夏季水汽输入多于其他季节，水汽收支主要受经向水汽输送的影响，且受到东亚夏季风和中纬度西风带自西向东的水汽输送控制。
Abstract:
Based on NCEP/NCAR monthly reanalyzed data, the variability of water vapor content, water vapor flux and water budget in Haihe River basin was analyzed, which used to reflect changes of the source of at-mospheric water. The water vapor content exhibited a decreasing trend during 1961-2010, and annual water vapor content reached its lowest level at 2009. The water vapor content of Haihe River basin is most abundant in summer. The zonal and meridional water vapor presented decreasing trends during 1961-2010. Unexpectedly, the zonal water vapor transported from west to east at whole years; while meridional water vapor flux varied with season, transported from north to south in winter and from south to north in summer. The water vapor content was input and presented decreasing trends at decade scale. The water vapor budget for Haihe River basin maintained positive value at seasonal scale, especially it presented higher value in summer than that in other seasons. The vapor budget is mainly controlled by meridional water vapor transport. Influenced by the East Asian monsoon and mid-latitude westerlies, water vapor mainly imported from west and south.