黑河中游金塔地区生态环境变化遥感监测

Monitoring the Ecology and Environment in the Middle Reaches of the Heihe River Using Remote Sensing

利用 1990年和 2 0 0 0年的TM遥感资料 ,在经过定标、几何校正和图像增强等图像处理的基础上对土地覆盖类型进行解译 ,从而实现黑河中游金塔地区的生态环境遥感动态监测 .从监测结果计算出黑河中游金塔地区 2 0 0 0年的生态环境相对于 1990年的生态环境变化如下 :人工用地增加34 17% ,农业用地增加 19 47% ,水体增加 8% ,湿地增加 6 3% ,未利用土地增加了 1 73% ,自然 /半自然植被减少 42 78% .

The Heihe River is the second large inland river by basin area in the arid areas of Northwest China, with a total area of {128 000} km 2. In the middle reaches of it, the desertification is severe because of the over-usage of irrigation water in the oasis agriculture areas, expending of farmland, over pasture and etc. Especially in the lower reaches of it, the ecology and environment are turning worse in recent years. A major monitoring area was selected in Jinta of the middle reaches of the Heihe River Basin and the Landsat TM data in summer of 1990 and 2000 was used for interpretation on computer screen, classification and setting up ecological and environmental investigation database (1∶{100 000}) combined with DEM, land cover/land use, land type data and etc., according to the ecological and environmental classification system. The dynamic monitoring results in 1990 and 2000 show that the changing percentage in area of 6 ground objects are as follows: land use and agriculture land use increasing by 34^17% and 19^47%, respectively, wet land and water-body also increasing by 6^29% and 8^03%, respectively; unused land increasing by 1^73%, and the biggest change is decrease in natural/semi-natural vegetation area, 42^78%. Dynamic monitoring found that the area of natural/semi-natural vegetation in the middle reaches of the Heihe River largely reduced. On the one hand, it is resulted from the increasing of cultivated land within oases, and is also resulted from the desertification, on the other hand. So it is a dangerous signal of large area desertification, if the natural/semi-natural vegetation reduces continuously and dramatically. In the past years, both the number and the area of small reservoirs increased remarkably in the middle reaches, which met the increasing water requirement due to largely increasing cultivated area. This is the direct cause of the cutting off runoff and the ecology and environment going from bad to worse in the lower reaches. So unified allocation of water utilization and development of save-water agriculture are very important.