Desertification over the tibetan plateau during 1971–2015 from a climate perspective

Wiley Online Library
https://onlinelibrary.wiley.com/doi/abs/10.1002/ldr.3575

Lan Cuo, Yongxin Zhang, Yongqiu Wu, Mei Hou

First published:13 February 2020 – https://doi.org/10.1002/ldr.3575

Abstract

Our understanding of desertification on the Tibetan Plateau (TP) is limited. This study aims to fill the knowledge gap by examining desertification and the underlying climatic factors during 1971–2015 on the TP using a dynamic vegetation model and observation based gridded climate data. Four factors including precipitation, days with threshold wind speeds, simulated vegetation fractional plant coverage and soil moisture in 0–40 cm depth are employed for the spatiotemporal desertification analyses. Simulated plant functional types and soil moisture are evaluated against the observations. By referencing the existing desertification maps in 1977, 1990, 2000, 2010 and 2015, the thresholds of the four factors are determined, and the temporally continuous annual areas of four types of desertification are reconstructed. The Qaidam Basin and Ngari Deserts are successfully identified by the above approach. The reduction of total desertification since 2000 is also consistent with national desertification surveys. Climate variation exerts the dominant control on desertification on the TP where population density is low, of which precipitation is the most important climate factor. Moderate but consecutive drought events correspond to the greatest desertification. During 1971–2015, the average total desertification area is 418,329 km2; among the four types of desertification, moderate desertification occupies the largest area (253,088 km2), followed by light desertification (105,583 km2) and extremely severe desertification (30,019 km2); severe desertification has the least coverage (17,597 km2). This approach can also be applied in the other regions given sufficient meteorological and ecological data.

Author: Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.