基于GPS与GIS 技术的长江上游山地冲沟的分布特征研究

长江上游山地生态环境十分脆弱，冲沟系统广泛分布，但对该区冲沟的发生演变一直缺乏定量研究数据。以西昌长山岭地区为对象，应用RTK-GPS对该区冲沟系统进行测量，建立数字高程模型（DEM）；同时基于GIS技术，探讨了从DEM上提取冲沟系统的方法，并以实测冲沟系统为依据，对所提取的冲沟系统的精度进行了对比分析。结果表明，利用DEM提取冲沟系统是一种快速、有效的方法。与此同时，分析了长江上游地区山地冲沟系统的分布特征，结果表明，小流域的沟壑密度为46．7m／hm^2，冲沟侵蚀速率高达191．9t／（hm^2．a），小流域内的土壤侵蚀为极强度土壤侵蚀，以控制冲沟侵蚀为主的水土保持措施，是该地区生态环境建设中值得重视的关键问题。

Assessing Gully Development in Upper Yangtze River Basin Based on GPS and GIS

Gullies are extensively distributed in the upper Yangtze river Basin,SW-China.But the development of these gullies is still not clear because there is no a reliable technique to be used for quantifying this issue.The objective of this study is to investigate the distribution characteristic of gully system and major factors affecting gully development in Changshanling area of Xichang,using GPS and GIS.We measured the gully system using RTK-GPS and established digital elevation mode(DEM) of the gully catchment,and proposed a method forextract gully system from the established DEM in frame of GIS.Our results indicated that our method for quantifying gullies from the DEM based on RTK-GPS survey is practical and effective.The gully density in Changshanling catchments was 46.7 m/hm~2,and annual average gully erosion amount was 191.9 t/hm~2,indicating a severe soil erosion and land loss in SW-China.Therefore,soil and water conservation measures should focus on controlling gully erosion for rebuilding ecological environment in the study area.