东亚干旱半干旱区空中水资源研究进展

系统回顾了近年来中外对东亚干旱半干旱区空中水资源方面的主要研究进展,主要包括大气水汽、云的分布特征、空中水资源的降水转化率及其影响因子等。东亚干旱半干旱区西部及东部水汽含量较中部高,背风坡水汽含量较迎风坡高,季风区及山脉地区云水资源高于盆地、沙漠上空。20世纪80年代中期以后,东亚干旱半干旱区对流层底部的水汽显著增多,其中夏季增加最为明显。在全球气候变化背景下,中国西北部分地区云水路径总体呈现上升趋势,同时呈现"东正西负"的东西向变化差异以及"北正南负"的反相位特征。大气环流、地表温度、下垫面地表特征等因子通过影响东亚干旱半干旱区的水汽输送及蒸散,进而改变东亚干旱半干旱区空中水资源,空中水资源的改变通过影响辐射收支、不同高度云量及第2次相变产生的云水含量进而对局地温度和降水产生影响。以往研究中,大部分主要针对东亚干旱半干旱区大气中的水汽含量和云平均状态的分布与变化特征,而与降水相关联的空中水资源的变化特征目前仍不清楚,有待系统深入地研究。 

A review of the research on atmospheric water resources over arid and semi-arid regions of East Asia

Based on recent studies of the atmospheric water resources over arid and semi-arid areas in East Asia (ASEA), the progress is reviewed. Many researches have shown that the water vapor content in the atmosphere over the western and eastern parts of ASEA is higher than that over the central ASEA, and the water vapor content above the leeward slope is higher than that in the windward slope. Cloud water resources over the monsoon region and mountainous areas are higher than over basins and deserts. The water vapor content in the lower troposphere over the ASEA has increased significantly, especially in the summer after the mid-1980s. Under the background of global climate change, the cloud water path over the northwestern part of China tends to increase generally with features of "positive in east and negative in west" and "positive in the north and negative in south". The atmospheric circulation, surface temperature and land cover characteristics all impact the air water resources over ASEA through influencing the water vapor transport and evapotranspiration. The changes in air water resources affect local temperature and precipitation by affecting the radiation budget, the cloud cover and the cloud water content produced by the second phase transition. At present, most of the researches mainly focus on the distribution and variation of water vapor content and cloud mean state over the study area. The characteristics of air water resources associated with precipitation are still unclear and need to be studied systematically.