基于MODIS-NDVI的云南省植被覆盖度变化分析

Analysis of Vegetation Coverage Change in Yunnan Province Based on MODIS-NDVI

植被覆盖变化监测是区域资源环境承载力研究的基础,本文通过计算2001-2016年MODIS-NDVI植被指数,辅以趋势分析、变异系数等方法,估算了2001-2016年云南省植被覆盖度,进而探讨了植被覆盖度的时空变化特征及与地形因子之间的分布关系。结果表明:(1) 2001-2016年云南省植被覆盖度呈显著增加趋势,增速为4.992%/10 a。(2)在空间上,植被覆盖度空间格局呈现由南向北、由西向东逐渐降低的特征,滇西、滇西南地区植被覆盖度最高,滇西北地区最低;植被覆盖度稳定性表现为由西南向东北方向波动性越来越大;滇东北地区植被覆盖度增加趋势明显优于其他区域,研究区内植被覆盖度变化趋势为增加、基本稳定和减少趋势的面积分别占49.53%、43.76%和6.71%。(3)植被覆盖度在2001-2006年、2006-2011年、2011-2016年3个时段的面积转移矩阵结果均表现为植被覆盖进化面积大于退化面积,二者的比值分别为1.42、1.63、2.01,植被覆盖情况呈持续改善趋势。(4)云南省植被覆盖度与地形因子之间的关系表现为,平均植被覆盖度随海拔增加呈先增加再减少、再增加、再减少趋势;随坡度的增加呈先增加再减少趋势;随坡向的变化呈由北向南逐渐减少趋势。

The monitoring of vegetation cover change is the basis of regional resource and environmental bearing capacity research. This paper estimates the vegetation of Yunnan Province from 2001 to 2016 by calculating the MODIS-NDVI vegetation index from 2001 to 2016, supplemented by trend analysis, and coefficient of variation. Next, the spatial and temporal variation characteristics of vegetation coverage and its distribution relationship with topographic factors are discussed in depth. Results are shown as follows:(1) From2001 to 2016, the vegetation coverage in Yunnan shows a significant increase, with a growth rate of 4.992%/10 a.(2) Spatially, the spatial pattern of vegetation coverage appears to be gradually decreasing from the south to the north and from the west to the east. The vegetation coverage is highest in the west and southwestern Yunnan and the lowest in the northwestern Yunnan. The stability of the vegetation coverage is characterized by increasing volatility from southwest to northeast; the increase of vegetation coverage in northeastern Yunnan was significantly better than other areas. The study region of the vegetation coverage change trend which was increased, basically stable and decreased, accounting for 49.53%, 43.76% and 6.71%, respectively.(3) The area transfer matrix results of vegetation coverage in the three periods from 2001-2006, 2006-2011, and 2011-2016 all showed that the vegetation cover evolution area was larger than the degraded area, and the ratios of the two were 1.42, 1.63, and 2.0. It indicates that the vegetation coverage shows a continuous improvement trend in the study area.(4) The relationship between vegetation coverage and topographic factors in Yunnan Province shows that the average vegetation coverage increases first, then decreases, then increases, and then decreases with the increase in altitude; it increases first and then decreases with increasing slope; Changes have gradually decreased from north to south.