地震灾区植被综合生态质量变化特征及与气候因子的关系--以5·12汶川地震灾区为例

Variation of Vegetation Ecological Quality and its Relationship with Climate Factors in Earthquake-stricken Area-A Case Study of 5·12 Wenchuan Earthquake-stricken Area

采用MODIS卫星归一化植被指数(Normalized Difference Vegetation Index,NDVI)和植被净初级生产力(Net Primary Productivity,NPP)遥感数据,反演汶川地震重灾区2000~2019年植被综合生态质量指数及其恢复率,并结合气候因子探讨该地区植被恢复的时空差异变化。结果表明:(1)2000~2019年,研究区植被综合生态质量在空间上从东北至西南呈对角式减少特征,东北方向植被综合生态质量区域改善,震中龙门山中段至南段和盆周低山地区受到地震、气候变化等多因子的耦合影响,植被综合生态质量呈现恶化趋势。(2)震后恢复阶段(2011~2019年),研究区植被综合生态质量改善明显,龙门山中段至南段东侧植被综合生态质量已得到恢复,但并未恢复至灾前最佳水平。(3)地震对平原、中山、耕地、林地和湿地的植被综合生态质量损伤较大,对高山的植被综合生态质量有一定的损伤,但无法判定地震对草地、灌木的植被综合生态质量是否有影响。(4)气候因子对植被综合生态质量恢复率的影响存在一定差异,降水比气温更能促进生态质量的恢复。

Using MODIS NDVI and MODIS NPP remote sensing data,the vegetation comprehensive ecological quality index and its restoration rate in Wenchuan earthquake-stricken area from 2000 to 2019 were retrieved,and the temporal and spatial variation of vegetation restoration in this area was discussed combined with climatic factors.The results show that:(1)From 2000 to 2019,the comprehensive ecological quality of vegetation in the study area showed a diagonal pattern in space(northeast to southwest),while the CVEQI in the northeast improved.The middle to the south section of Longmen Mountain and the low mountain area around the basin were affected by the coupling of earthquake,climate change and other factors,and the comprehensive ecological quality of vegetation showed a deteriorating trend.(2)In the post earthquake recovery stage(2011~2019),the comprehensive ecological quality of vegetation in the study area was significantly improved,and the comprehensive ecological quality of vegetation in Longmen Mountain had been significantly improved.The comprehensive ecological quality of vegetation had been restored from the middle section to the east of the south section of Longmen Mountain,but it did not restore to the best level before the disaster.(3)The earthquake had a great damage to the comprehensive ecological quality of vegetation in plain,Zhongshan,cultivated land,forest land and wetland,and had a certain damage to the comprehensive ecological quality of vegetation in high mountains,but it was impossible to determine whether the earthquake had an impact on the comprehensive ecological quality of vegetation in grassland and shrubs.(4)There were some differences in the effects of meteorological factors on the restoration rate of comprehensive ecological quality of vegetation in different degrees.Precipitation could promote the restoration of ecological quality better than temperature.