黄河源区气候变化及人为扰动的生态响应

The ecology response to climate changes and human disturbance in the source regions of the Yellow River

利用黄河源区1959-1999年的气象和水文资料,分析了该区气温、蒸发量、风速、降水量、径流量以及多年冻土的演变规律,揭示了源区对气候变化和人为扰动的生态响应趋势。研究表明:近40年黄河源区气温升温趋势明显,源区升温高达0.58℃/10 a,成为全国升温最高的地区,但气温的升高并没有引起蒸发量的总体上升,反而有所下降,蒸发量下降可能与风速下降有关;气温的升高导致多年冻土层变薄植被失去保护,地表蒸发增强,同时冻土层上限下移,径流量也受到影响;降水有所减少,但其变化趋势并不是十分明显,这与西北地区整体的降水规律有着较为明显的不同,显示出黄河源区的独特的地域性;降雨量与径流量的变化趋势基本一致。气候变化和人为扰动共同造成了草原退化、水土流失加剧、自然灾害频发、冰川萎缩、冻土退化、水体减少等生态问题,气候变化是造成黄河源区生态退化和破坏的根本原因,大规模生态移民可能是保护黄河源区生态的根本办法。

Using the data of meteorology and hydrology in the source regions of the Yellow River dring 1959 - 1999 ,we analyzed the evolvement regularity of temperature, evaporation capacity, wind speed, precipitation, runoff, and permafrost in order to show the ecological response trend to climatic changes and human disturbance. The results indicated that temperature intensify trend was obvious in the source regions of the Yellow River during the past 40 years, and in this region the temperature increased by 0.58 ℃/10a, becoming the area where temperature increasing the mostly comparing whole country, however, the rising of the temperature did not caused the overall rising of evaporation, but dropped to some extent instead, which relating to wind speed dropping; Rising of temperature led to permafrost become thin, and the plants lost the protection, furthermore, the ground evaporation become strengthen, at the same time, the upper permafrost shifted down, and the runoff was influenced too; Precipitation was reduced to some extent, but variation tendency was not obvious, in this point its precipitation law was obvious different with the whole Northwest in China, and that demonstrated its unique and regional characteristics; the variation tendencies of precipitation and runoff were basically identical. Climatic changes and human disturbance had caused many ecological problems, such as grassland degradating, soil erosion aggravation, natural disaster taking place frequently, glacier shrinking and the water body reducing, climatic changes was the basic reason causing the ecology degradation and destroy, and extensive ecological immigrants might the basic method to protect the ecological in the source regions of the Yellow River.