Variation of vegetation in the Northeast China and its response to meteorological factors

Based on the SPOT-VGT NDVI and meteorological data during 1998—2008,the change of annual average vegetation NDVI and the relationship with climatic factors were studied.In addition,the various vegetation NDVI changes in growing season and the correlation and hysteretic nature with climatic factors were also studied in this paper.The results showed that,the general status of vegetation in Northeast China were well in the past 11 years,most of the vegetation did not change significantly.The annual average NDVI was affected by temperature and precipitation significantly,with temperature more significantly,and the influence degree of precipitation was higher in the northern region than southern.Different vegetation had different NDVI in growing season,and the growth status changes were different,but the changes were not obvious.NDVI in growing season was affected significantly by temperature and precipitation in the same period,with temperature more significantly,which was more evident in ten days scale.The response of NDVI in Northeast region to temperature had a time lag of about 10~20 days,while had a time lag of about 20 days for precipitation.