Changes in frozen ground in the Source Area of the Yellow River on the Qinghai-Tibet Plateau, China, and their eco-environmental impacts
Changes in frozen ground in the Source Area of the Yellow River on the Qinghai-Tibet Plateau, China, and their eco-environmental impacts
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DOI：
10.1088/1748-9326/4/4/045206
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发表时间：
2009-10-01
影响因子：
6.7
通讯作者：
Chang, Xiaoli
中科院分区：
文献类型：
--
作者：
Jin, Huijun;He, Ruixia;Chang, Xiaoli
黄河源区位于青藏高原东北部季节性冻土、间断冻土和连续冻土的镶嵌过渡带。在垂直方向上，永久冻土与冰冻作用是相互连接或分离的。后者可进一步分为浅层（深度至多年冻土表8米）和双层多年冻土。自20世纪80年代以来，气温一直以每年0.02摄氏度的平均速度上升。人类活动也显著增加，导致永久冻土的区域性退化。多年冻土下限上升了50-80米。平均最大冻深减少了0.1-0.2米。多年冻土层上层的水温上升了0.5-0.7摄氏度。多年冻土退化的一般趋势包括面积范围从连续和不连续到零星和斑块状多年冻土，多年冻土变薄，和talks的扩展。孤立的永久冻土斑块要么在面积上显著减少，要么变成季节性冻土。多年冻土的退化导致地下水位下降，湖泊和湿地缩小，草原生态系统从高山草甸变为草原。高寒草地退化将导致冻土进一步退化，生态环境恶化，表现为荒漠化扩大和水土流失加剧。
The Source Area of the Yellow River is located in the mosaic transition zones of seasonally frozen ground, and discontinuous and continuous permafrost on the northeastern Qinghai-Tibet Plateau. Vertically, permafrost is attached or detached from frost action. The latter can be further divided into shallow (depth to the permafrost table 8 m) and two-layer permafrost. Since the 1980s, air temperatures have been rising at an average rate of 0.02 degrees C yr(-1). Human activities have also increased remarkably, resulting in a regional degradation of permafrost. The lower limit of permafrost has risen by 50-80 m. The average maximum depth of frost penetration has decreased by 0.1-0.2 m. The temperatures of the suprapermafrost water have increased by 0.5-0.7 degrees C. General trends of permafrost degradation include reduction in areal extent from continuous and discontinuous to sporadic and patchy permafrost, thinning of permafrost, and expansion of taliks. Isolated patches of permafrost have either been significantly reduced in areal extent, or changed into seasonally frozen ground. Degradation of permafrost has led to a lowering of ground water levels, shrinking lakes and wetlands, and noticeable change of grassland ecosystems alpine meadows to steppes. The degradation of alpine grasslands will cause further degradation of permafrost and result in the deterioration of ecological environments as manifested by expanding desertification and enhancing soil erosion.