基于AVHRR/NOAA影像的天山北坡近10a植被变化

提出一套基于遥感和GIS技术的干旱区植被变化和生态环境质量初步评价的研究方法,在天山北坡及其典型区域三工河流域应用取得满意结果.研究表明:1)1992—1998年天山北坡植被覆盖度和生物量持续增加,与同期温度和降水变化趋势一致,从植被角度响应了天山北坡气候向暖湿发展的态势.2)1987—1998年三工河流域从前山带到北部沙漠区植被覆盖度和生物量显著增加,尤其是绿洲外围的北部沙漠区和荒漠过渡带;从增加的幅度看,平原区增幅明显大于山区,后期大于前期;植被指数与6～7a温度、降水的均值呈现出明显的正相关,和6～7a蒸发潜力的均值表现出负相关,三工河流域植被变化显著地响应了6～7a时间尺度的气候变化.

Vegetation Change during the Last 10 Years Derived from Satellite Image in the North Slopes of the Tianshan Mountains

A method for studying vegetation change in the arid areas and preliminary quality evaluation of ecological environment has been put forward based on the technology of remote sensing and GIS, and a satisfactory consequence has been obtained by applying the method to the north slopes of the Tianshan Mountains and a specific area —— Sangong River basin, based on satellite remote sensing data and meteorological data. It is found that: (1) Vegetation coverage and biomass in north slopes of the Tianshan Mountains were increasing during 1992-1998, which responded to a climatic shift from warm-dry to warm-humid; the increasing extent in the plain areas was more than that in the mountainous areas, and the increasing extent during 1995-1998 was more than that during 1992-1995. (2) The vegetation coverage and biomass in 1987-1998 increased from foothill belts to northern deserts in the Sangong River basin, especially in northern deserts and transition zones outside of oasis; the increasing extent in plain areas was more than that in mountains areas, and that in the anaphase was more than that in the prophase. (3) No evident change of vegetation index with monthly, seasonal and annual changes in temperature and precipitation were found. However, there were obviously positive correlations with temperature and precipitation averaged over 6～7 years, and evident negative correlation with potential evaporation averaged over 6～7 years, remarkably showing a climate change in the time-scale of 6～7 years.