基于MODIS的民勤绿洲植被覆盖变化定量分析

Quantitative analysis on the vegetation coverage changes of Minqin Oasis based on MODIS

以典型沙漠绿洲-民勤绿洲为研究区,利用MODIS陆地3级标准数据产品MOD13,通过改进的植被覆盖度估算模型对2000～2010年7月的植被覆盖度进行了估算,并对其进行分级,通过空间叠置定量分析了不同级别植被覆盖度的分布特征及动态变化。研究发现,从2000～2010年11年间,民勤绿洲轮廓变化明显,绿洲面积明显缩小,荒漠进一步扩张,极低覆盖度植被面积增加1106.01km2,相当于研究区总面积26.95%,中高覆盖度和高覆盖度植被面积分别减少133.63km2和54.75km2,各占研究区总面积的3.26%和1.33%;研究表明,11年来民勤绿洲面积萎缩明显,岛状绿洲大量消失,其中以西北部最为严重。

In this paper,the typical Minqin oasis were taken as research area.Using standard MODIS data products of MOD13 and improved vegetation coverage estimation model,the vegetation coverage from July 2000 to July 2010 were estimated and classified,the distribution characteristics of vegetation coverage and the dynamic changes of different vegetation coverage were analyzed through quantitative analysis of special overlay.Analysis showed that during the study years Minqin Oasis changed dramatically,the area of oasis shrinked significantly and desert expanded further more,the increase area of very low vegetation coverage was 1106.01 km^2 and it took up 26.95% of the whole study areas.The vegetation coverage types of intermediate and high grade reduced by 133.63 km^2 and 54.75 km^2 respectively,accounted for 3.26% and 1.33% of the whole study areas.In a whole,the area of Minqin oasis shrinked dramatically,a large number of island oasises were lost,and the northwest was the most serious part.