北疆不同生态功能区近30年来植被盖度时空变化

Characteristics of Spatio-temporal Variation of NDVI in Different Ecological Function Zones in North Xinjiang in Recent 30 Years

NDVI时空变化不仅可反映生态环境的变动趋势,而且还能揭示出区域植被的恢复与退化状况。以1981—2003年GIMMS NDVI和1998—2010年SPOT VGT NDVI时间序列数据为基础,运用NDVI最大值合成法和趋势分析法,分析了北疆近30年来不同生态功能区及不同植被类型NDVI时空变化规律。结果表明:1)从北疆大功能区来看,1981—2003年期间NDVI平均值变化呈周期波动,增幅缓慢,并以2002年为转折期,北疆整体植被改善程度不断增强。2)从不同生态功能区看,1981—2003年伊犁河谷地区、天山北坡和阿尔泰山的南部生态区等主要生态功能区植被改善明显,在准噶尔盆地荒漠生态区及其东部区植被呈轻度植被退化;1998—2010年北疆大部地区植被恢复明显,伊犁河谷、天山北坡中段绿洲平原区植被改善程度达到极显著水平。3)北疆植被的改善或退化趋势可能与同期实施的生态建设工程以及区域气候的总体变化有关。

Spatial and temporal variations of NDVI can not only reflect the changing trend of the ecological environment, but also reveal the recovery situation and degeneration of regional vegetation. According to the data of time series, which were GIMMS NDVI from 1981 to 2003 and SPOT VGT NDVI from year 1998 to 2010, this paper analyzed the spatial and temporal variations of ecological function area and NDVI of different vegetation types of northern Xinjiang in recent 30 years, with the maximum synthesis method of NDVI and the trend analysis method. The results showed as follows ： （ 1 ） From the perspective of functional areas in Northern Xinjiang, the average value of NDVI grew slowly and changed with the periodic fluctua- tion during the period from 1981 to 2003 ,while as a turning period in 2002 ,the improvement of the whole vegetation enhanced continuously. （ 2 ） From the perspective of different ecological function districts, the vegetation of ecological function areas in Yili River Valley, the northern slope of Tianshan Mountains and the south of Ahai Mountains were obviously improved during the period from 1981 to 2003 ,while the veg- etation of desert ecological area and eastern region of the Junggar basin were degenerated mildly. The veg- etation in most parts of northern Xinjiang restored significantly during the period from 1998 to 2010, and the vegetation improvement reached the extremely significant level in the Yili River Valley and the plain oasis area in the middle of the northern slope of Tianshan Mountains. （3） The improvement or degradation trends of vegetation in northern Xinjiang may be related to the implementation of ecological construction and the overall regional climate change during the same period.