摘要
利用2000—2015年每年8月份的MODIS卫星影像数据,计算眉山市同期的归一化植被指数(NDVI),并根据降水和气温的相对一致性选取2000年和2014年两个典型年份,以其NDVI为基础反演植被覆盖度,通过差值植被指数的差值分级,量化分析眉山市2000—2015年的植被状况,结果表明:眉山市NDVI均值从2000年的0.773 8增加到了2015年的0.810 7,6区县除东坡区之外NDVI均值均呈升高趋势;2014年与2000年相比,全市低覆盖度、中覆盖度、中高覆盖度植被区域面积分别降低了7%、3%和14.44%,高覆盖度植被区域面积增加了17.53%;不同区县之间植被覆盖度变化主要集中在中高覆盖度和高覆盖度两个等级。以NDVI为基础分析了植被的时间变化特点,并利用2000年和2014年8月份的NDVI植被梯度与差值植被指数从全市及各区县两个尺度进行讨论分析,结果表明:全市植被改善区域面积超出退化区域面积6 525 hm^2,彭山县、仁寿县和青神县植被以改善为主,改善区域面积分别超出植被退化区域面积11.01%、7.66%和4.05%;洪雅县、东坡区和丹棱县植被以退化为主,退化区域面积分别高出植被改善区域面积11.58%、3.33%和0.77%;生态退化区域主要集中在山地区、水域区以及道路沿线。
In this paper,the normalized difference vegetation index（ NDVI） was calculated based on the MODIS satellite image data taken from August 2000 to August 2014,which was in turn used to estimate vegetation coverage in2000-2015 in Meishan city. The vegetation change was quantitatively assessed with the NDVI of 2000 and 2014 which was chosen according to the relative uniformity of precipitation and temperature. The result showed that the average value of NDVI increased from 0. 7738 in 2000 to 0. 8107 in 2015,and it was also slowly rising in six counties except for Dongpo District; Compared with the year of 2000,the areas with low,medium and medium-high vegetation coverage reduced by 7%,3% and 14. 44%,respectively,in 2014 while the area with high coverage increased by 17. 53%; The change of vegetation coverage between different districts mainly concentrated in the medium-high and high grades. The vegetation change characteristic in different time was analyzed based on NDVI,and the NDVIvegetation gradients and difference vegetation index between August 2000 and August 2014 were discussed at two levels,i. e.,the city and its districts. The statistical results in NDVI showed that the vegetation quality improved area exceeds the degraded area by 6525 ha. The vegetation in Pengshan,Renshou and Qingshen counties has been improved,with the area 11. 01%,7. 66% and 4. 05% higher than the degraded area,while Hongya,Dongpo and Danling counties have more degenerated vegetation area,which 11. 58%,3. 33% and 0. 77% more than the improved area,respectively. The degradation area is mainly concentrated in the mountain area,water area and along the road.
出处
《中国城市林业》
2018年第1期11-16,共6页
Journal of Chinese Urban Forestry
基金
林业公益性行业科研专项经费项目(201404301)
