青藏高原人类活动的极端环境风险评价

Extreme Environmental Risk Assessmentof Human Activities on the Qinghai-Tibet Plateau

青藏高原极端的自然环境对生命体构成严峻威胁,开展环境风险评价对于综合风险防范措施的制定具有指导意义。选用海拔、地形起伏度、地被指数、水网密度指数、温湿指数、风寒指数、人体舒适度及绝对含氧量自然因子指标,采用地理探测器和地理加权回归两种模型,构建以1 km×1 km栅格为研究单元的青藏高原极端环境指数分区,并判断极端环境与人类活动的协调性关系。结果表明:(1)自然因子指标中地被指数、水网密度指数、海拔、绝对含氧量对乡村居民点分布贡献率较大,且高原全年体感最佳期出现在8月,1月的寒冷条件极大限制着人类活动。(2)两种模型构建的高原极端环境指数(EEI)均呈现出由东南向西北递减趋势,根据EEI数值高低将高原环境划分为低极端区、较低极端区、中极端区、较高极端区和高极端区。低极端区仅局限于藏南谷地,较低极端区以高原边缘河谷和横断山区为主体,中极端区包括柴达木盆地、川西高原、青海南部及藏东南谷地等地区,较高极端区面积占比最大且广布高山,高极端区分布在羌塘高原和西部少量高大山脉。(3)低-较低极端区环境与人类活动协调性高,中-高极端区突显出的环境与人类活动间的矛盾则与放牧活动、开展基建工程和城镇化建设有关。

This paper used altitude,relief degree of land surface,land cover index,river network density index,temperature-humidity index,wind-chill index,degree of comfort and absolute oxygen content,for these indicators regulate biological pressures and subsistence.This paper used geographical detectors and geographically weighted regression to weigh the indicators above,and then constructed 1 km×1 km grid of the extreme environment index zone of the Qinghai-Tibet Plateau,also Identified the coordinated relationship between extreme environments and human activities.The results show that:(1)Among the indicators that have a greater impact on the distribution of villages are the land cover index,river network density index,altitude,absolute oxygen content.The comfortable period of the Qinghai-Tibet Plateau is August,and January is not suitable for human activities.(2)The results of both models present similar trend in extreme environmental index and show a trend from southeast to northwest.According to the variation of extreme environmental index,Qinghai-Tibetan plateau was categorized into the least,less,average,more,and most environmentally extreme areas.The least environmentally extreme area is the Tibet-South Valley and it accounts for the smallest area size.The less environmentally extreme areas include valleys on thefringes of high plateau and in the Hengduan Mountain areas.The areas of average extreme environmental condition include the Qaidam basin,western Sichuanplateau and southern part of the Qinghai Province.The more environmentally extreme areas are mostly the mountainous areas and account for thelargest area size.The most environmentally extreme area is the Changtang Plateau.(3)The environment and human activities in the least-less environmentally extreme areas are highly coordinated.The contradiction between the environment and human activities in average-most environmentally extreme areas is related to grazing activities,construction of engineering facilities and urbanization.