Dynamics Of Vegetation Cover And Its Relationship With Climate Change In Chongqing

More and more evidences indicate that the Earth's temperature gets warmer and warmer in recent 100 years, especially in the North Hemisphere, extreme climate events occurred frequently, How does vegetation, as the most sensitive part of earth ecosystem, responds to climate changes? Then, has comparatively closed position in chongqing, responded similarly? In this paper, MODIS-EVI data between 2000 to 2009 as the main source of information on vegetation changes. By using the average vale method, differencing, correlation analysis and multivariable linear regression model, analysis the chongqing city vegetation changes from different time and space, reveals the vegetation change on regional climate changes over the past decade, for the Chongqing environmental protection, and adapt to global climate change has important significance. We came to the conclusions:1. Vegetation cover of the Chongqing city trends to increase indistinctly as a whole during 2000 to 2009 with a linear regression trend of 0.0033. in addition to urban areas and the Three Gorges Reservoir area and districts expansion has decreased, other parts of the EVI values were increased. Compared with the previous five years, EVI average of the last five years increased 5.79%.2. Changes in the EVI value during the year, EVI lowest in January and july maximum, individual years, lowest in February , the highest June. During the year, the EVI value increased first and then decreased. April, May, June, October, Novermber, December has the higher Increased of mouths linear regression trend, Minimum in August.3. the meteorological factors of Chongqing is like a wave forward, annual temperature is 17.71, the trend of temperature is increasing, linear regression trend is 0.0725, higer than china 50 years temperature trend. Average annual precipitation is 1142.2mm, the trend of precipitation is decreasing, linear regression trend is -2.554mm per year, average annual sunshine duration is 1196.7 hours, the trend of sunshine duration is decreasing. Linear regression trend is -10.3 hours per year.4. During the year, the meteorological factors increased first and then decreased. extreme climate events occurred frequently, rainstorm, drought, cold, high temperature have the different effects on vegetation. High temperature make the EVI values of vegetation reduce, rainstorm have the little effect on the EVI values, and sometimes promote, EVI values higher.5. vegetation and meteorological factors over the past decade in the year showed a significant positive correlation, temperature have the highest correlation, followed by precipitation, sunshine hours minimum. EVI exhibite a significant time-lag effect to Precipitation during the year. Interannual changes in temperature lags the highest correlation with vegetation, vegetation and precipitation also have a higher correlation with sunshine lag associated with the vegetation, but not high.