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基于连续 5年的观测 ,对比研究了马占相思人工林和果园两种地表类型上地表径流的各自特点 ;讨论了季节性地表径流的差异与系统水分结构问题 ;探讨了根据实际资料求取发生地表产流的降雨量临界值的方法 ,此方法以综合考虑未发生产流的最大降雨量和已发生产流的最小降雨量为基础 ;并得到了如下的一些结果 :1)本区域不同强度的大气降水频度分布比较均匀 ,但降水量主要由少数几场特大降水带来 ,并且降水量的季节分配极不平均 ,湿季 (4～ 9月 )降水量占全年的 85 .5 %。 2 )地表径流的季节差异更大 ,果园在湿季的地表径流量占全年的93.8% ,马占相思林占 95 .1% ,作者认为在降水量存在较大干湿季差别的地区 ,对于越难于发生地表径流的下垫面 ,这个值会越高。3)马占相思地表径流系数在逐年减小 ,果园的变化较大。4)一次性降雨量对地表径流量的影响在这两种地表类型上都很明显 (r>0 .85 ) ;一次性降雨强度对地表径流的影响只有在中等降雨量 (6～ 16 mm)下才表现明显 (r>0 .87) ,对于较小和较大降水量 ,径流量与降雨强度关系都不大 ;径流系数受一次性降雨强度的影响很明显 (林地 r>0 .92 ,果园 r>0 .77)。 5 )马占相思和果园一次性“最大可能”地表径流产流的雨量临界值 ,分别为5 .1m m和 2 .8mm。
Based on the observation of five years in a row, the characteristics of surface runoff on two land types, Acacia mangium plantation and orchard, were comparatively studied. The differences of seasonal surface runoff and the system moisture structure were discussed. This method is based on the combination of the maximum rainfall with no runoff and the minimum rainfall with runoff occurred. Some results are as follows: 1) The regional rainfall intensity with different intensities The distribution of atmospheric precipitation frequency is relatively uniform, but the precipitation is mainly caused by a few extraordinary rainfalls, and the seasonal distribution of precipitation is extremely uneven. The precipitation in the wet season (April-September) accounts for 85.5% of the whole year, . 2) The seasonal variation of surface runoff is greater. The orchard’s runoff in wet season accounts for 93.8% of the whole year and Acacia forest accounts for 95.1%. According to the author’s opinion, in areas where there is a large difference in precipitation between wet and dry seasons, This value will be higher for the more difficult to surface runoff underlying surface. 3) Acacia mangium surface runoff coefficient decreased year by year, orchard changes. 4) The impact of one-off rainfall on surface runoff is obvious on both types of land surface (r> 0.85). The effects of one-off rainfall on surface runoff only occur in moderate rainfall (6-16 mm) (R> 0.87). For the smaller and larger precipitation, the relationship between runoff and rainfall intensity was not significant. The runoff coefficient was significantly affected by the one-off rainfall intensity (r> 0.92, Orchard r> 0 .77). 5) The critical value of the “maximum” surface runoff yield of Acacia mangium and orchard at one time was 5.1 m and 2.8 mm, respectively.