Variation characteristics of NDVI and its response to climatic change in the growing season of Changbai Mountain Nature Reserve during 2001 and 2018

Abstract

To understand the dynamics of temperate forest in Northeast Asia and its response to climate change under the scenario of global change, we examined the temporal and spatial changes of normalized difference vegetation index (NDVI) and their correlation with temperature and precipitation of Changbai Mountain Nature Reserve in the growing season during 2001 and 2018, based on the remote sensing database of MODIS with a resolution of 250 m, land surface temperature data with a resolution of 1 km and meteorological data in the studied and surrounding area. The results showed that, in the growing season of 2001-2018, the averaged NDVI value of the study area was 0.711. Vegetation coverage was relatively high, increasing with a rate of 0.0025·a-1. The temperature showed an extremely significantly increasing trend (0.032 ℃·a-1), the rate of which was higher than that at global level. Precipitation also showed a significantly increasing trend (5.54 mm·a-1) with increased interannual variation. Spatially, NDVI generally was higher in the northwest and decreased with elevation. During the study period, the area with increased NDVI accounted for 46.2%, mainly concentrated in the north and south central high-altitude areas, while 53.8% of total area remained unchanged or slightly decrease. NDVI of the study area was mainly affected by temperature. At the annual scale, NDVI and land surface temperature were positively correlated, with 90.2% presented positive correlation and 43.6% significantly correlated. At the monthly scale, the impact of temperature on NDVI was more significant at the beginning and the end of growing season.