中文摘要：

利用向量合成法,对1959—2005年间图们江干流代表水文站的逐年逐月径流量进行统计分析,并计算近期平均集中程度和最大径流量的出现时间.结果表明：1）在20世纪60—70年代间,图们江流域径流集中度逐渐下降,80年代后开始整体呈上升趋势,其中上游的集中度变化幅度最大,中游的平均集中度最低,下游的平均集中度最高.2）在20世纪60—90年代间,图们江流域径流集中期逐渐提前,整体集中期约提前10 d;21世纪后,集中期较20世纪90年代推迟约3 d,上中游在7月和9月出现了＂双峰型＂的集中期特征.

英文摘要：

The mean concentration degree and the concentration period were computed and analyzed by using the observed monthly streamflow of key hydrological control stations in Tumen River from 1959 to 2005 based on vector composition.The results indicated that ： 1） The concentration degree in Tumen River basin decreased in 1960 s—1970 s and increased from 1980 s;the concentration degree has changed most in the upper reaches,the maximum mean concentration degree showed in the middle reaches,and the minimum showed in the lower reaches.2） Generally the concentration period forewent about 10 d during 1960 s—1990 s;after the entered the 21 st century,the concentration period deferred about 3 d compared with 1990 s＇,and exhibited obvious ＂double peak＂ in the middle and upper reaches in July and Septemper.