Abstract
The Tibetan Plateau (TP) is one of the most sensitive regions to global climate warming, not only at the inter-annual time scale but also at the altitudinal scale. We aim to investigate the contrasting effects of temperature and precipitation on vegetation greenness at different altitudes across the TP. In this study, interannual and elevational characteristics of the Normalized Difference Vegetation Index (NDVI), temperature, and precipitation were examined during the growing season from 1982 to 2015. We compared the elevational movement rates of the isolines of NDVI, temperature, and precipitation, and the sensitivities of elevational NDVI changes to temperature and precipitation. The results show that from 1982 to 2015, the elevational variation rate of isolines for NDVI mismatched with that for temperature and precipitation. The elevational movements of NDVI isolines were mostly controlled by precipitation at elevations below 2400 m and by the temperature at elevations above 2400 m. Precipitation appears to plays a role similar to temperature, and even a more effective role than the temperature at low elevations, in controlling elevational vegetation greenness changes at both spatial and interannual scales in the TP. This study highlights the regulation of temperature and precipitation on vegetation ecosystems along elevation gradients over the whole TP under global warming conditions.
Highlights
The Tibetan Plateau (TP) is known as the ‘roof of the world’ and ‘the Earth’s third pole’
Normalized Difference Vegetation Index (NDVI) dynamics influenced by precipitation on the northeastern and southwestern TP was investigated by recent studies [23]
Our results indicate that 8km Global Inventory Modeling and Mapping Studies (GIMMS) NDVI showed similar elevational contrasting effects of temperature and precipitation across the TP compared with 250-m Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI
Summary
The Tibetan Plateau (TP) is known as the ‘roof of the world’ and ‘the Earth’s third pole’. Previous studies indicated that a continuous increase in temperature leads to vegetation greenness amplitude changes on the TP [20,26,27], and impacts the leaf-unfolding date [28,29]. Higher air temperature could indirectly result in vegetation growth reduction by increasing land surface evaporation and limiting water availability [31,32]. A comprehensive analysis was conducted by Li et al to quantify the contribution of temperature, precipitation, and solar radiation on vegetation growth [39]. Elevation and slope influenced the distribution of vegetation cover while such an effect could be attributed to the variation of temperature and water availability [44,45]. Pepin et al has illustrated elevation-dependent warming in alpine areas [48]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
