运用近景数字摄影测量方法,获得在不同人工降雨时段黄土模拟小流域高精度、高分辨率的DEM数据,并以地面坡度及其组合形态的变化为切入点,通过对比分析和理论验证探讨黄土小流域降雨侵蚀过程中地貌的发育特征。研究结果表明:1)在不同的侵蚀发育阶段,黄土地貌平均坡度及坡度组合持续变化。平均坡度在地貌发育幼年期呈加速增长趋势,到了壮年期增长幅度呈递减性变化;坡度组合以侵蚀临界角度为轴点呈持续逆转变化,侵蚀临界坡度单元所占面积基本保持稳定。2)黄土地貌地面坡度及其组合形态的变异不仅能有效表征黄土高原地貌形态的空间变异规律,也可以对黄土地貌侵蚀规律和它产生的时间规律进行高分辨率的地貌认识和划分。
The topographic feature is one of the main factors that influence the process of soil erosion and sediment yield of small watershed. It is very necessary to quantitate the topographic feature of small watershed and get the correlative parameters rapidly. According to the process resemble principle and statistic analysis of the topographic feature of small watershed on the Loess Plateau, the small tested watershed is designed. Based on 25 artificial simulated rainfalls, the dynamic development process of the topographic feature of the tested small watershed is studied by means of photogrammetry and GIS technology. DEMs at nine different erosion levels were picked up with a high precision and resolution. The spatial variation of slope and its composition derived from these DEMs are mainly discussed through comparison analysis and experimental validation. The result shows: firstly, in the process of rainfall erosion, the velocity of the increase of the surface mean-slope is increasing during erosion prophase and decreasing during erosion activity stage. The decrease of smoother slope balanced with the increase of steeper slope at erosion critical angle, namely, the proportion of erosion critical angle histogram resultants is keeping almost steady. In addition, the variation of slope composition reflects not only the spatial variation of loess morphology, but also the rule of loess erosion and the developing process as well.
[1] 陆中臣,贾绍凤,黄克新,等. 域地貌系统[M]. 大连:大连出版社,1991.32~41.
[2] 刘东生,孙继敏,吴文祥.中国黄土研究的历史、现状和未来[J]. 第四纪研究, 2001,21(3):185~207.
[3] Schumn S A.The Role of Creep and Rainwash on the Retreat of Badland Slope[J]. Amer, Jour.Sci,1956,254:693-706.
[4] Veneziano D, J D Niemann. Self-similarity and multifractality of topography surface at basin and subbasin scale[J].J.Geophys. Res, 1999,104(12):797-812.
[5] 马新中,陆中臣,袁宝印. 流域地貌系统的侵蚀演化与耗散结构[J]. 地理学报, 1993,48(4):367~375.
[6] 石 辉,田均良,刘普灵. 小流域坡沟侵蚀关系的模拟试验研究[J]. 土壤侵蚀与水土保持学报,1997,3(1):30~42.
[7] 蒋定生,周 清,范兴科,等. 小流域水沙调控正态整体模型模拟试验[J]. 水土保持学报,1994,8(2):25~30.
[8] 金德生,陈 浩,郭庆伍, 流域物质与水系及产沙间非线性关系实验研究[J]. 地理学报,2000,55(4):339~448.
[9] 汤国安,赵牡丹,李天文,等. DEM提取黄土高原地面坡度的不确定性[J]. 地理学报,2003,58(6):824~830.
[10] 赵牡丹,汤国安,陈正江,等. 黄土丘陵沟壑区不同坡度分级系统及地面坡谱对比[J]. 水土保持通报,2002,22(4):33~36.
[11] 张科利, 张竹梅. 坡面侵蚀过程中细沟水流动力学参数估算探讨[J]. 地理科学, 2000, 20(4):326~330.
[12] 张丽萍,朱大奎,杨大源. 黄河中游土壤侵蚀与下游古河道三角洲演化的过程响应[J]. 地理科学, 2001,21(1):52~56.
[13] 张光辉,刘国彬. 黄土丘陵区小流域土壤表面特性变化规律研究[J]. 地理科学, 2001,21(2):118~122.
[14] 卢金发,刘爱霞. 黄河中游降雨特性对泥沙粒径的影响[J]. 地理科学,2002,22(5):552~556.
[15] 郑粉莉,高学田. 坡面土壤侵蚀过程研究进展[J]. 地理科学,2003,23(2):230~235.
[16] 朱显谟. 黄土高原水蚀的主要类型及其有关因素[J]. 水土保持通报,1982 ,2 (3) :36~41.
[17] 肖学年,崔灵周,王 春,等. 模拟流域地貌发育过程的空间数据获取与分析[J].地理科学,2004, 24(4):399~443.
[18] 承继成,江美球. 流域地貌数学模型[M].北京:科学出版社, 1986.136~146.
[19] 胡世雄,靳长兴. 坡面土壤侵蚀临界坡度问题的理论与实验研究[J]. 地理学报,1999,54(4):347~356.
