前汛期北江洪水过程水汽汇与河水流量的关系

RELATIONSHIP BETWEEN THE MOESTURE SINK OVER THE BEIJIANG BASIN AND THE FLOOD DISCHARGE OF THE RIVER

本文分析了１９８０～１９８４年４～６月和１９９４年６月洪水过程北江流域的大气水汽汇特征及其与河水流量的关系．结果表明：前汛期洪水过程的前期大气一般连续存在超过一定值的较强水汽汇，时间为１周左右，洪水的发生是强水汽汇连续产生的径流的积累所致，北江流域洪水期水汽汇的极大峰值一般比石角站的洪峰流量超前２天左右，本文结果为洪水的预报提供一条新思路．

In this peper the charactendics of the atmospheric moisture sinks and their relationships tothe flood tdischarges over the Beijiang Basin are analysed by using the data in the flood Periodfrom April tO June for five years from 1980 to 1984 and the flood period in June, 1994. The vertically integrated value of moisture sink is computed, which reflects the net amount of the moisture transported from the atmasphere to the underlying surface. The main findings may be summarized as follows: 1) Pronounced atmospheric moisture sinks surpass some critical value for about one week prior to the flood peak arrival. The accumulation aam convergence of run-off due to the strong moisture over a large domain in a period lead to fooding. 2) There exists good relationship between the yertically integrated value of moisture sink and flooding. The competed resulta thow that the flood discharge would reach its peak value two-day later than that of the moisture sink value. 3) The tesults mentioned above provide a new method to the flood fotecast. Further work needs to be done in ceder to quantitatively predict the flood discharge using information about the moisture sink.