| Changes in the global climate are imperceptibly affecting the functions and structures of land-based ecosystems.They pose a serious threat to human production and livelihood,and they also impede the sustainable development of the world.Therefore,how to mitigate global warming and improve the global climate has become the common concern of all mankind.Vegetation is the “indicator” of the global climate defense.It connects the atmosphere,soil and water.The change of vegetation can well reflect the change of the regional ecological environment.The change in vegetation can be reflected by the vegetation coverage.Therefore,studying the dynamic changes in vegetation coverage plays a decisive role in the study of global climate change.In the study area of this paper,the Guangxi Zhuang Autonomous Region,which has a relatively weak ecological environment,the paper selected MODIS images from 2000 to2015 as the remote sensing data source.On the ARCGIS 10.1 platform,the vegetation coverage was calculated using the normalized vegetation index,and Dynamic changes and influencing factors were analyzed.The main findings of this article are as follows:(1)Using the Pixel Binary Model to Estimate the Vegetation Coverage in Guangxi and analyze its spatial and temporal variation.In the 16 years from 2000 to 2015,the vegetation coverage in Guangxi showed an overall trend of increase.From 2000 to 2005,the vegetation coverage was slightly fluctuated.In 2002,the vegetation coverage showed a small peak and then declined.In 2004,It start to rise.During the period from 2005 to 2010,the vegetation coverage in the first four years is on an upward trend,with a marked decline in 2009 and a minimum in2010.This phenomenon may be related to the special drought in the autumn of 2009 and the spring of 2010.After 2010 Vegetation coverage began to rise again and then slightly fluctuated.In 2015,vegetation coverage reached 86.17%.(2)The type of vegetation cover in Guangxi and the trend of changes were analyzed.It can be concluded that in all levels of vegetation coverage,the vegetation coverage of high vegetation is relatively stable and basically maintained at a stable rate of 50%,the other several types of vegetation coverage evolution is more dramatic,but from the evolution of the type of view In the 16 years,the coverage of vegetation in Guangxi showed a good trend.By analyzing the trend of vegetation coverage,it can be found that the proportion of basic invariance and slight improvement is the highest,reaching a total of 72.38% of the total area of Guangxi,while the total percentage of improvement is higher than that of deteriorating,So the overall coverage of vegetation in Guangxi showed an improving trend.(3)Analysis of influencing factors on vegetation coverage.According to the analysis,among the climatic factors,only precipitation has a significant effect on the vegetation coverage,while the temperature has no significant effect on the vegetation coverage during the study period.Among the topographic factors,the significant impact on vegetation coverage is elevation and In terms of slope,vegetation coverage increased first and then decreased with increasing altitude and slope.However,the slope direction had no significant effect on vegetation coverage.Among the human activities,land reclamation rate was mainly at work and vegetation coverage The degree of decline with the increase of the land reclamation rate,in addition,the policy factors such as returning farmland to forests also have a certain impact on the vegetation coverage. |
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