青藏高原湿地遥感监测与变化分析

Remote Sensing Monitoring and Change Analysis of Wetlands in the Tibetan Plateau

青藏高原是中国湿地分布较为集中的地区之一,也是全球变化的敏感区。了解青藏高原湿地分布与变化对湿地保护和全球变化研究具有重要意义。基于Landsat 8 OLI(operation land imager)数据,使用面向对象分类方法和人工解译相结合的方式得到2016年青藏高原湿地分布数据,结合2008年湿地分类数据以及高程、流域界线等辅助数据,分析了青藏高原的湿地分布现状和2008—2016年的湿地变化情况。结果表明:①2016年青藏高原研究区湿地总面积为115584 km2。其中,湖泊湿地面积为48737 km2,沼泽湿地面积为34698 km2,河流湿地面积为15927 km2,洪泛湿地面积为15035 km2,人工湿地面积为1188 km2。②2008—2016年,青藏高原湿地总面积增加3867 km2,主要表现为湖泊、河流和洪泛湿地的增加,但同时沼泽湿地减少5799 km2。③青藏高原的湿地分布与变化表现出显著的区域差异性。自然湿地的分布及面积变化集中在4~5km高程范围内,而人工湿地的变化则集中在2~4 km高程范围内;湖泊和洪泛湿地的增加集中在内流区,河流的增加及沼泽的减少集中在外流区。④青藏高原的气温和降水均呈上升趋势,与湿地总体变化呈正相关;各流域冰川面积的变化与湿地变化也具有相关性;人为因素对青藏高原的湿地变化以消极作用为主。该研究为青藏高原环境变化研究与湿地保护提供了有益支持。

Tibetan Plateau is a region with more concentrated wetland distribution in China, which has always been a sensitive region of global change, and its wetland distribution and change are of great value to the study of the change of water resources and environments in China. Based on Landsat 8 OLI(operation land imager), we adopt the method of object-oriented classification and manual interpretation to obtain the wetland distribution of the Tibetan Plateau in 2016, and the wetland classification data in 2008, as well as the auxiliary data of elevation and watershed boundary. The present situation of wetland distribution and wetland changes in the Tibetan Plateau from 2008 to 2016 were analyzed. The results show that: ① In2016, the total area of the Tibetan Plateau wetland was 115 584 km2, the area of lake wetland was 48 737 km2, marsh wetland area was 34 698 km2, river wetland area was 15 927 km2, flood wetland area was15 035 km2, constructed wetland area was 1 188 km2. ② From 2008 to 2016, the total area of wetland in the Tibetan Plateau increased 3 867 km2, mainly from the increase of lake, river and flood wetland and the decrease of the marsh wetland. ③ In different watersheds and altitudes, the distribution and variation of wetland in the Tibetan Plateau showed significant regional differences. ④ Both temperature and precipitation in the Tibetan Plateau showed upward trends, which was positively correlated with the overall change of the wetlands;the change of glacier area in drainage basins had a certain correlation with the wetland change;human activities mainly played a negative role in the wetland change of the Tibetan Plateau. This paper provides a useful support for the study of environmental change and wetland conservation in the Tibetan Plateau.