中文摘要：

2011-2013年,大致以半年为周期,利用Leica ScanStation 2三维激光扫描仪对广东五华县莲塘岗崩岗进行6次野外定位监测,运用ArcGIS软件对6次监测数据进行对比分析,阐明崩岗流域侵蚀产沙的时空变化,提供精细化研究成果。研究结果表明,莲塘岗崩岗年平均侵蚀模数高达222 408t/（km2·a）,主要侵蚀区位于海拔111-131m的崩积锥分布区,占侵蚀总量的55.6%,且崩岗中、下部位侵蚀强度高于崩岗上部。崩岗侵蚀量随崩岗表面坡度变化呈现正态分布的特征,侵蚀量最大值位于崩岗40°-50°的坡面部位。单位面积的崩岗侵蚀量大致随崩岗表面坡度的增大而加大,表明崩岗流域内坡度越大,侵蚀越强烈。在6次5个监测周期内,崩岗侵蚀方式具有明显变化,沟道发育是崩岗侵蚀发生的主要触发因素之一。前3个监测周期中,崩岗以沟道快速下切、侧蚀和溯源侵蚀为主,兼有小规模崩塌;后2个监测周期中,崩岗以重力侵蚀为主,侵蚀量先减少后增大。莲塘岗崩岗目前正处于壮年期阶段,地形是崩岗发育的主要影响因素。地形因素导致崩岗水力侵蚀与重力侵蚀交替进行,两者共同作用使得崩岗侵蚀发展过程呈现出螺旋式上升的演化模式。

英文摘要：

Using Leica ScanStation 2three-dimensional laser scanner to monitor Liantanggang collapsing hill and gully in Wuhua county of Guangdong for 6times from 2011 to 2013,in half a year cycle roughly,with a comparative analysis of the measured data through ArcGIS,the authors studied the spatial and temporal variation law of erosion and sediment yield in a small watershed scale in detail.The results indicate that the average annual erosion modulus of Liantanggang collapsing hill and gully is up to 222 408t/（km2·a）.The main erosion area is the colluvial cone range,accounting for 55.6% of the total amount of erosion,at an altitude from 111 mto 131mand the erosion rate of the middle-lower zones is higher than that of the upper.The amount of erosion shows a normal distribution with the slope changing and the maximum is located on the slope of 40°to 50°.But the erosion in per unit area increases with the gradient increasing,which means the erosion is more intense in steeper slope.Within the five observation periods the erosion form shows a clear change,and gully development is one of its main motivating factors.Rapid-cutting,lateral erosion and retrogressive erosion is the main feature of Liantanggang collapsing hill and gully during the first 3periods following some small-scale landslide,but gravity erosion dominants the last 2periods making the total amount of erosion first decline and then increase.Liantanggang collapsing hill and gully is in the prime stages.Terrain is the major factor affecting the current development.Terrain factors can lead to transformation between gravitational erosion and water erosion.Their combined effect makes collapsing hill and gully erosion a spiraling evolution model.