Dynamic Changes of NDVI in the Growing Season of the Tibetan Plateau During the Past 17 Years and Its Response to Climate Change.

Xianglin Huang,Dong He,Tingbin Zhang,Jiaqing Miao,Xiaojuan Bie,Guihua Yi,Jingji Li,Xiaobing Zhou

doi:10.3390/ijerph16183452

Abstract

The fragile alpine vegetation in the Tibetan Plateau (TP) is very sensitive to environmental changes, making TP one of the hotspots for studying the response of vegetation to climate change. Existing studies lack detailed description of the response of vegetation to different climatic factors using the method of multiple nested time series analysis and the method of grey correlation analysis. In this paper, based on the Normalized Difference Vegetation Index (NDVI) of TP in the growing season calculated from the MOD09A1 data product of Moderate-resolution Imaging Spectroradiometer (MODIS), the method of multiple nested time series analysis is adopted to study the variation trends of NDVI in recent 17 years, and the lag time of NDVI to climate change is analyzed using the method of Grey Relational Analysis (GRA). Finally, the characteristics of temporal and spatial differences of NDVI to different climate factors are summarized. The results indicate that: (1) the spatial distribution of NDVI values in the growing season shows a trend of decreasing from east to west, and from north to south, with a change rate of −0.13/10° E and −0.30/10° N, respectively. (2) From 2001 to 2017, the NDVI in the TP shows a slight trend of increase, with a growth rate of 0.01/10a. (3) The lag time of NDVI to air temperature is not obvious, while the NDVI response lags behind cumulative precipitation by zero to one month, relative humidity by two months, and sunshine duration by three months. (4) The effects of different climatic factors on NDVI are significantly different with the increase of the study period.

Highlights

The Global Climate Change and Terrestrial Ecosystem (GCTE) is one of the core research topics of the International Geosphere Biosphere Programme (IGBP), which has received great attention from the international scientific community as well as the international community in general [1]
Wang et al [15] studied the response of Normalized Difference Vegetation Index (NDVI) to climatic factors in Kansas from 1989 to 1997 and found that different vegetation types responded to air temperature and precipitation in different ways, and had different lag times
The NDVI of Tibetan Plateau (TP) has a lag effect on air temperature and precipitation, and there is a spatial difference in the lagging level, ranging from 10 days to 90 days

Summary

Introduction

The Global Climate Change and Terrestrial Ecosystem (GCTE) is one of the core research topics of the International Geosphere Biosphere Programme (IGBP), which has received great attention from the international scientific community as well as the international community in general [1]. Index (NDVI) is a quantitative parameter that can be used to characterize and reflect the sensitivity of the earth’s surface vegetation coverage and growth status, and it is one of the best indicators for quantitatively characterizing vegetation dynamic changes [2]. Since the 1980s, NDVI has been widely used in studying the impact of climate on vegetation. NDVI dynamics and its correlation with climatic factors have become one of the important research topics of global change [4,5,6].

Results

Discussion

Conclusion