摘要
土壤侵蚀不仅表现黄土高原强烈的现代地貌过程,也是其生态环境恶化的象征,其地貌演化和土壤侵蚀互为因果,现代研究表明黄土高原半干旱小流域的沟谷侵蚀产沙占其水土流失总量的重要部分,近年有关沟谷侵蚀的定量研究成果,加深了人们对沟道侵蚀危害的认识,为土地资源的合理利用、沟谷危害的评价等提供了科学依据。传统的沟谷侵蚀定量研究是采用实地量测的方法,现代的数字摄影测量技术的发展为估算沟谷侵蚀研究提供了一个经济高效方法。本研究采用的髙分辨率数字高程模型是由3期历史航空照片根据数字摄影测量方法制作而成,利用它对黄土高原半干旱区一个小流域的1959～1981年及1981～1999年两个时段内沟谷侵蚀产沙量进行估算,将流域侵蚀产沙的实测值与估算结果进行评价。并指出此方法在沟谷侵蚀产沙量估算方面的统计学意义及在未来应用时要注意的问题;根据流域侵蚀产沙结果分析历史时期人类活动的影响:人类活动在一定程度上改善了环境,绝大部分泥沙被拦截在流域里,同时沟道侵蚀加剧,如何采取措施减少流域坡面和沟道的侵蚀,是目前人们所面对的问题;此外,结合流域水沙统计数据的DEM的侵蚀空间分析,结果表明坡面流、重力侵蚀及沟谷的下切是导致流域土壤侵蚀的主要原因。
Soil erosion not only represents the intense geomorphologic process of the Loess Plateau but also the symbol of the environment deterioration, soil erosion and the geomorphologic evolvement are interdetermined. Present research shows gully plays a leading role in the catchment morphologic evolution and ground surface dissected extension. The semi-arid cathchment of the Loess Plateau of China is severely affected by soil erosion as it is revealed by the commonly occurring deep and wide gullies. Recent studies in the loess hillgully terrain area show gully erosion has a very significant contribution to total soil loss. Traditionally, gully erosion had been measured using field survey techniques, the advances in computing powering digital photogrammatric solution are now offering an affordable and cost effective way of estimating the gully erosion. This paper used the digital elevation models （2 m grid）, which constructed from multi-date （ 1959 - 1981 and 1999） aerial photographs （ 1：55 000, 1：20 000 and 1 ： 35 000） as a tool to compute the sediment yield by gully erosion in a small catchment of 9. 06 km^2 located in the Loess Plateau of China. Soil loss of two periods ： 1959 - 1981 and 1981 - 1999 was estimated from computed gully volumes using soil bulk density, compared the measured data with the estimated result of which, valued the DEM-based techniques for estimating soil loss, indicated that it should be possible to rapidly estimate soil loss, and recommendations were made for future applications of DEMs for assessment of soil loss as well. Based on the estimated results the impacts of human activities were analyzed： human activities is a double-edged sword which can improve the environment and accelerate the erosion at the same time, people still needs to do more to reduce soil erosion. Combined the statistic data with the DEM-based spatial analysis, it is clear that most of the soil loss are due to overland flow, mass movements and gully deepening.
出处
《地球信息科学》
CSCD
2008年第4期533-538,共6页
Geo-information Science
基金
香港特区政府研究资助局支持项目(HKU701701E)
关键词
沟谷侵蚀
数字高程模型
侵蚀产沙量
半干旱流域
gully erosion
digital elevation models
sediment production rate
semi-arid catchment
