渤海淡水存留时间分析

Freshwater residence time in Bohai Sea

利用渤海蒸发量、降水量、入海径流量、渤海及黄海盐度数据,基于淡水比例方法估算了渤海的淡水存留时间,并设计敏感性实验,定量分析了渤海淡水通量对渤海淡水存留时间的影响。结果表明,渤海年平均(1965—1980、1986—1992、1994、1996年)淡水存留时间为2.6年,并呈现弱上升的趋势。20世纪80年代的淡水存留时间(4.6年)与20世纪60年代(3.0年)相比,增加了近50%。渤海淡水存留时间随淡水输入的增加而缩短。与净降水量(降水量与蒸发量之差)相比,渤海淡水存留时间对入海径流量变化更敏感,因而流域调水的环境规划应予以充分关注。

A box model based on freshwater fraction method was used to estimate the freshwater residence time（FRT）in the Bohai Sea.The data used in this study include the evaporation,precipitation,river discharge,and salinity in the Bohai Sea and its surrounding region,the Yellow Sea.Sensitivity analysis was conducted to quantitatively assess the effects of freshwater flux on the water exchange between Bohai Sea and Yellow Sea.The results indicated that the interannual variability in the salinity in Bohai Sea was mainly caused by the freshwater supply from Yellow River,the largest river around Bohai Sea.During the periods of 1965-1980,1986-1992,1994,and 1996,the mean FRT in Bohai Sea was 2.6 years,and had a weak upward trend.In the 1960s,the FRT was 3.0 years;but in the 1980s,it increased to 4.6 years,with an increment of about 50%.The FRT decreased with increasing freshwater supply,and in general,was more sensitive to river discharge than to net precipitation flux（the difference between precipitation and evaporation）,suggesting that sufficient attention should be paid on the formulation of environmental policy on the regulation of Yellow River water resources.