近30年来西藏那曲湿地变化及驱动力探讨

Changes of wetland in Nakchu in the last 30 years and analysis of driving forces

以RS／GIS为主要手段，以基于60年代末航片绘制的那曲县1：10万地形图、1990年TM遥感数据、2000年ETM遥感数据和1：25万DEM数据为主要数据源，结合那曲县温度、降水等资料，对那曲县湿地分布、面积变迁和驱动力进行分析，结果表明：那曲县湿地变迁总体趋势自20世纪70年代以来呈萎缩趋势。空间差异表现为：那曲县西部小型断陷湖盆谷地区域的湿地面积自70年代以来一直呈现萎缩趋势，东部、南部高山宽谷地区、河源区湿地自经历70～90年代扩张后，在90年代面积转为萎缩。气候波动和频繁的人类活动是湿地变迁的驱动力，湿地的地质、水文等背景因素的不同可能是变迁差异的重要原因。

The wetland distribution, area change and driving force have been analyzed by means of RS/GIS, and take 1：100 000 topographic maps of Nakchu, based on aerial photographs in the late 1960s, remote sensing images of Landsat TM in 1990, Landsat ETM in 2 000 and the 1：250 000 DEM data as main data sources, as well as combined with the temperature and precipitation data in Nakchu. The results indicate the wetland change in Nak- chu presented degradation trend from 1970s. The spatial differences show that the wetland acreage in small-sized faulted lake basin valley areas of western Nakchu was degenerated from 1970s, while increased in high mountainwide valley and river source areas of eastern and southern Nakchu during 1970 - 1990, and decreased after 1990 s. Climatic fluctuations and human activities are also the driving forces of wetland change, and the differences of wetland geological and hydrological factors maybe an important reason for wetland change.