1990—2011年若尔盖高原土地覆盖变化

以1990—2011年的Landsat TM遥感影像为数据源，利用ENVI的面向对象法和Google Earth提取地物信息及自然水系与人工沟渠的分布格局，结合1967—2012年降水量和气温数据，分析气候变化对土地覆盖的趋势性影响。结果表明:2011年建设用地和荒漠的面积分别是1990年的5.84倍和1.35倍，林地面积主要受人口增长和伐木等人类活动影响以0.66 km²/a的速率不断减少，水面面积受水文周期和降水量影响呈现波动性变化，草地面积增加，植被覆盖度先减后增，泥炭沼泽湿地面积由于气候变暖、人工开渠和自然水系溯源下切的叠加作用影响以78.62 km²/a的速率快速萎缩；若尔盖高原人工沟渠控制的泥炭沼泽有完全由人工沟渠排水和自然水系与人工沟渠共同排水两种输水模式；持续的人工沟渠排水活动显著影响着泥炭沼泽的蓄水量，制约着泥炭沼泽的维持并加速泥炭沼泽脱水萎缩。

Land cover change in Zoige Plateau during 1990-2011

Based on the data source of the remote-sensing images of Landsat TM in 1990-2011, object-oriented ENVI method and Google Earth were used to analyze the land cover as well as spatial distribution patterns of natural river networks and artificial ditches. Combined with the annual precipitation and temperature data in 1967-2012, the impact of climatic change on land cover was analyzed. The results show that the area of construction land and desert in 2011 is 5.84 and 1.35 times of that in 1990, respectively. Forestland area decreased with a rate of 0.66 km²/a under the influence of population increase and human activities. Water surface area was in a fluctuating variation due to the influence of both hydrological cycle and precipitation. Grassland area always increased, in which the vegetation coverage decreased first and then increased. The peatland swamps rapidly shrank at a rate of 78.62 km²/a due to the combined effects of climatic warming, artificial ditches and headward erosion of natural river networks. There are two primary dewatering patterns of peatland swamps in Zoige Plateau, dewatering by artificial ditches and joint dewatering by both natural river networks and artificial ditches. Persistent dewatering by artificial ditches significantly influences the water storage capacity, restricts the maintenance of peatland swamps and accelerates their shrinkage.