京津冀空中水资源的时空变化特征及成因

强化分析空中水资源有助于合理利用水资源。基于1960～2015年NCEP/NCAR月平均再分析数据集,采用一元线性方程等方法,计算了京津冀区域水汽总量和水汽通量,并分析了该区域空中水资源的时空变化特征及成因。结果表明,1960年代以来,京津冀区域四季及年平均水汽总量均呈显著减小趋势,且夏季最为明显;受由东南向西北递减的水汽输送强度的影响,京津冀区域四季及年平均水汽总量均呈现由东南向西北随纬度增大而减少的趋势,且南北分布差异夏季最大,冬季最小;孟加拉湾和西风带纬向环流为该区域水汽输送的主要通道,其中夏季水汽输送最大,主要来自孟加拉湾、南海和西太平洋;京津冀区域西、北面环山,东部为平原的特殊地形造成其水汽总收支以弱流出为主;虽然该区域水汽输送以纬向为主,但经向流入的显著减少是造成该区域水汽收支随时间增加而减少的主要原因。研究成果可为京津冀地区水资源的开发利用提供参考。

Characteristics and Causes of Temporal and Spatial Variation of Atmospheric Water Resources Over Beijing-Tianjin-Hebei

Strengthened analysis of atmospheric water resources is conducive to rational utilization of water resources. Based on NCEP/NCAR monthly mean reanalysis data set from 1960 to 2015, the total water vapor volume and water vapor flux in Beijing-Tianjin-Hebei region were calculated by using the method of linear equation, and the spatial-temporal variation characteristics and causes of atmospheric water resources in this region were analyzed. The results show that since the 1960s, the annual and seasonal integrated water vapor in Beijing-Tianjin-Hebei region has been decreasing significantly, and the summer is the most obvious. The decreasing from southeast to northwest of the water vapor transport causes the distribution of annual and seasonal integrated water vapor which decreased with increase of the latitude from southeast to northwest. The difference between north and south is the biggest in summer and the smallest in winter. The bay of Bengal and the westerly zone are the main channel for the transportation of water vapor to the area. The maximum water vapor transport is in summer, which main comes from the bay of Bengal, the South China Sea and the Western Pacific. The total water vapor budget in Beijing-Tianjin-Hebei region is basically balanced, with weak water vapor outflow. The water vapor input shows a downward trend, while the output shows an upward trend. The region of Beijing-Tianjin-Hebei has a special topography with mountains to the west and north, and the eastern part is a plain, which result in a weak outflow of water vapor. Although the zonal direction is the main water vapor transport channel in the region, the significant decrease of meridional inflow is the main reason for the decrease of water vapor budget. The results can provide reference for the development and utilization of water resources in Beijing-Tianjin-Hebei region.