Change Of Fractional Vegetation Cover And Analysis Of Driving Force In Sichuan Province

Vegetation is an important part of the whole ecosystem,and its changes have an important influence on the global energy cycle and the biological and chemical properties of matter.Fractional Vegetation Cover is the most important index to measure vegetation coverage.It directly reflects the situation of regional ecological environment and plays an important role in indicating the change of regional ecosystem.Sichuan province is an irreplaceable ecological barrier in the upper reaches of the Yangtze River.The study of Fractional Vegetation Cover change in Sichuan province is of great significance to the environmental quality of Sichuan's terrestrial ecosystems and the regulation of the ecological processes in the upper reaches of the Yangtze River.Based on the MODIS image data of three phases in July,2000,2007 and 2015,the vegetation coverage of three phases in 2000,2007 and 2015 is estimated,and the variation characteristics of FVC in the study area for the last 15 years are analyzed,combined with topographic data and meteorological data at the same time,based on the MODIS image data of July,2000,2007 and 2015.Data and population,GDP data,using the pixel two model and linear regression analysis to study the driving factors of the change of FVC in Sichuan province.The results are as follows:(1)The Fractional Vegetation Cover in Sichuan is generally high,and the average Fractional Vegetation Cover in Sichuan from 2000 to 2015 is 70.42%.The distribution of Fractional Vegetation Cover in Sichuan province has obvious regional characteristics.The area of high Fractional Vegetation Cover area is the most extensive in the northwest of Sichuan Province.The areas of all vegetation cover mainly in Wenchuan,Lixian and Barkam counties.The middle,low and non Fractional Vegetation Cover are scattered in the high mountain plateau area in Northwest Sichuan,and the vegetation in the southwest mountainous area of Sichuan Province is covered with vegetation.The coverage is mainly covered by high vegetation,among which the salt edge and the Hui Li county are mainly covered by vegetation;the basin in the mountainous area is mainly covered with full vegetation,and the West Sichuan plain and the hilly area of the basin are mainly covered by high vegetation.(2)The average value of 2000-2007 annual change of Fractional Vegetation Cover is 0.3375%,the Fractional Vegetation Cover changes mainly stable;the third level and fourth level of Fractional Vegetation Cover of vegetation coverage increased,fifth level of Fractional Vegetation Cover of Fractional Vegetation Cover is reduced.The average value of 2007-2015 annual change of Fractional Vegetation Cover is-2.4422%,the Fractional Vegetation Cover changes to reduce third;Fractional Vegetation Cover of Fractional Vegetation Cover increased,vegetation area fourth and fifth of the coverage tends to decrease.(3)The natural factors such as terrain factors,climatic factors,population density and social and economic factors such as ecological engineering all affect the change of FVC.From 2000 to 2007,there was a significant negative correlation between slope gradient,slope aspect and temperature factor in the driving factors of FVC change.From 2007 to 2015,slope factor showed a significant positive correlation,while slope aspect factor was significantly negatively correlated,and temperature factor showed a significant positive correlation.The population density has significant regional characteristics on the change of FVC.In the past 2000-2007 Years,the total FVC increased with the increase of population density.In the 2007-2015 years,the FVC decreased with the increase of population density.The FVC of Sichuan province is generally high and has obvious regional characteristics.In 2000-2015 years,the FVC of Sichuan province increased first and then decreased,and the change was not significant.Natural factors and social and economic factors have important impacts on FVC in Sichuan province.