应用灰色模型推算长江上游人类活动增沙量的新尝试

由于长江上游人类活动增沙影响的复杂性和区域性,加上缺乏足够的实测水、沙量资料序列和试验数据,使得难以按白色系统准确描述人类活动的增沙影响。本文根据长江上游宜昌站60年代和80年代两个丰沙段的水沙量资料,采用灰色系统理论,分别建立了反映60年代和80年代长江上游来沙量逐年累积变化的状态模型GM(1,2)。通过对状态模型的重演和对比分析,发现人类活动对长江上游的增沙影响相当大。据本文推算,如按目前的人类活动增沙速率发展下去,50年后,长江上游宜昌站年均来沙量将由50午代的5.2亿t、80年代的6.59亿t增加到7.51亿t。

A New Attempt to Calculate the Increment of Sediment Yield by Human Activities through the Grey Theory Model in Upper Changjiang River Basin

Due to the complexity and regionalism of the influence of human activities on the increment of sediment yield in upper Changjiang River basin,in addition to lack of enough data of runoff and sediment load and insitu observation and experimental data,it is difficult to exactly describe the influence of human activities on increasing sediment yield in the light of white system.Based on the data of runoff and sediment during the two peroids with high sediment yield in the sixties and eighties observed at Yichang Hydrologic Station,located at the outlet of the upper Changjiang River basin,the status models of GM(1 ,2) which represented the variations of annual accumulated sediment yield from the upper Changjiang River basin in the sixties and eighties were set up by using grey theory system.Through repeating the status models by exchanging the data of sediment and runoff in the sixties and eighties and contrast analysis,it was shown that human activities had a great influence on the increment of the sediment yield in upper Changjiang River basin. According to the calculation,if the increment of the sediment yield by human activities were kept on at the present rate,the annual average sediment yield in Yichang Hydrologic Station would increase from 520 million tons in the 1950s and 659 million tons in the 1980s to 751 million tons in the 2040s.