Spatio-temporal Variation Characteristics of Vegetation Coverage and Its Response to Climate in Hainan Island in Recent 20 Years
Based on MODIS NDVI data,temperature and precipitation data of 18 cities and counties in Hainan Island from 2001 to 2020,the spatio-temporal variation of vegetation coverage and its response to climate in Hainan Island over the past 20 years are studied by Mann-Kendall mutation test,univariate linear fitting and correlation coefficient analysis.The results are as follows:During 2001-2020,the maximum value of annual average NDVI is located in Baisha and the minimum value is in Haikou.The regional NDVI value is mainly in an increase trend,and the average NDVI growth trend of the whole is-land mutated around 2012,and then the growth rate accelerated significantly.The high value of seasonal average NDVI is located in Qiongzhong,Wuzhishan and Baisha,while the low value is in Haikou,Wen-chang and Dongfang.The average NDVI value of the whole island is highest in summer,and all seasons share an increasing trend of average NDVI in recent 20 years,with the largest increase in winter and the smallest increase in autumn.The monthly average NDVI value is largest in August and smallest in Febru-ary,and that of all the months in recent 20 years shows an increasing trend with largest increase in De-cember and smallest increase in November.The inter-annual variation of average NDVI is mainly affected by temperature and has no significant correlation with precipitation.The monthly variation of average ND-VI is influenced by both temperature and precipitation,of which temperature performs more significantly.The monthly average NDVI value of the whole island has the strongest response to the previous month's temperature and is highly correlated to the current month's precipitation.The NDVI value of most areas presents a significant positive correlation with the temperature of the previous month and the precipitation of the current month.
万方数据
维普
