丝绸之路青海道县域植被覆盖时空动态遥感分析

Remotely sensed analysis of county vegetation cover in Qinghai Silk Road region

丝绸之路经济带是新时期中国提出的重大国家战略,建设好丝绸之路经济带的前提是保护和改善生态环境,因此,定量监测和评估其生态环境质量状况意义重大,特别是对生态地位极其重要的青海省更是如此.本文以MODIS植被指数合成产品为遥感数据,采用像元二分模型,以表征生态环境变化指示器的植被盖度为指标,对青海省境内古丝绸之路(青海道)途径的22个县域,2004～2013年间的植被覆盖状况进行了研究.结果显示:10年间,青海道地区植被覆盖整体上以基本保持不变(占比61%)和得以改善(占比23%)为主,局部地区退化.其中,青海道地区东部的湟水流域和青南高原东南部整体上植被生长状况好转,青海道地区西部的柴达木盆地与东昆仑山地区局部,植被生长状况以基本保持不变为主,总体上呈现退化趋势,退化地区的植被以低覆盖度植被为主.研究结果可以作为青海道地区县域生态环境本底基础数据,也可以为开展青海道沿线地区项目投资、建设与发展潜力及可能存在的生态环境风险评估提供科学依据.

The Silk Road Economic Belt(SREB)which was proposed by China in the new era is a major national strategy.However,protecting and improving its ecological environment is the precondition for building the SREB.It is therefore very important to quantitatively monitor and evaluate its eco-environment quality,especially for Qinghai Province with the important and fragile ecological environment.Taking Fractional Vegetation Cover as an indicator of measuring eco-environmental change,and using the MODIS(Moderate-resolution Imaging Spectroradiometer)vegetation index synthetic products data and the dimidiate pixel model,this paper studied the vegetation cover conditions from 2004 to 2013 in twenty-two counties of Qinghai Silk Road(QSR)region that the ancient Silk Road passed through Qinghai province churchyard.The results showed that the vegetation cover was mostly in remaining constant(accounting for61%)and improvement(accounting for 23%),and vegetation cover was degraded in some local area.In the eastern part of QSR region,especially,in the Huangshui Valley and Southern Qinghai Plateau the vegetation growth status had a definite improvement.In the west of QSR region,especially,in the Qaidam Basin and the east Kunlun Mountains region,the vegetation growth status remained basically unchanged,and the overall degradation trend was observed.The vegetation in the degraded areas was dominated by lowcoverage vegetation.This research results can be used as the basic data of ecological environment,and can also provide a scientific basis for risk assessment of the project investment,construction and development potential and possible ecological environment along the QSR.