甘肃省NDVI时空演变特征及其与区域气候的响应

Spatio-temporal Variation of NDVI and Its Response to Regional Climate in Gansu Province

利用2001—2015年的MODIS-NDVI遥感数据,基于ENVI和Arc GIS空间分析技术定量探讨甘肃省的植被覆盖在研究期内的时空变化特征。按自然地理区域将甘肃省分为3个部分,与同期的气温、降水数据相结合,研究植被覆盖变化与区域气候之间的响应关系。结果表明:1)2001—2015年间,甘肃省整体植被覆盖以每年0.004 1的速率呈上升趋势,表明在研究期内甘肃省的植被覆盖有所改善,但在空间上存在明显的差异性;2)2001—2015年甘肃省的年降水量呈下降趋势,年平均气温呈上升趋势,但变化速率都较低,表明研究期内甘肃省的干热化趋势有所缓和:3)植被覆盖与降水呈正相关,与温度呈现负相关,在区域尺度上降水对植被覆盖影响要大于温度。

Long time NDVI sequences can indicate the characteristics of vegetation cover on the surface and are widely used in the study of large scale surface vegetation cover changes. This study used MODIS-NDVI data sets in 2001 to 2015 to quantitatively study the spatio-temporal variations of vegetation cover in Gansu Province based on ENVI and Arc GIS spatial analysis techniques. According to the natural geographical region,Gansu Province was divided into three parts,which were combined with the temperature and precipitation data of the same period to study the response relationship between vegetation cover change and regional climate. The results showed that:( 1) Vegetation coverage in Gansu Province increased by the rate of 0. 004 1 per year from 2001 to 2015,indicating that the vegetation cover in GansuProvince has improved during the study period,while there are obvious spatial differences.( 2) The annual precipitation in Gansu Province shows a decreasing trend,while the annual average temperature shows an upward trend. But the change rates of the both were relatively low,indicating that the trend of dry heating in Gansu Province had eased during the study period.( 3) Vegetation cover is positively correlated with precipitation,negatively correlated with temperature,and the influence of precipitation on vegetation coverage is greater than the temperature at the regional scale.