Qiang Zhang, Keke Fan, Vijay P. Singh, Changqing Song, Chong-Yu Xu, Peng Sun
[Qiang Zhang, Keke Fan, Changqing Song]. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China.
[Qiang Zhang, Keke Fan, Changqing Song]. Faculty of Geographical Science, Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China.
[Qiang Zhang, Keke Fan, Changqing Song]. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China.
[Vijay P. Singh]. Department of Biological and Agricultural Engineering and Zachry Department of Civil Engineering, Texas A&M University, College Station, Texas, USA.
[Chong-Yu Xu]. Department of Geosciences, Oslo University, Blindern 0316, Oslo, Norway
[Peng Sun]. College of Territory Resources and Tourism, Anhui Normal University, Anhui 241000, China
Abstract: The Himalayan-Tibetan Plateau (HTP), often known as the Third Pole and the “Asian Water Tower”, is the source of water for many Asian rivers and in turn for hundreds of millions of people living downstream. The HTP has direct impacts on the establishment and maintenance of Asian monsoon, and therefore on the climate of its surrounding areas. Besides, soil moisture plays a critical role in the hydrological cycle and is a critical link between land surface and atmosphere. Hence, soil moisture was greatly emphasized by Global Climate Observing System Programme as an Essential Climate Variable. However, little is known about soil moisture changes on the HTP from a long-term perspective. By comparing remote sensing and model soil moisture datasets against in-situ observations from 100 observatory stations, here we find that Noah performed better than other soil moisture datasets. In past years, soil moisture first decreased and then increased obviously. In most regions on HTP, precipitation changes can be taken as the major cause behind soil moisture variations. In future, there is persistently decreasing soil moisture trend since ~2010 with a decreasing rate of -0.044 kg/m2/10a, -0.031 kg/m2/10a and -0.0p 88 kg/m2/10a under RCP2.6, RCP4.5 and RCP8.5 scenarios, respectively, in CMIP5 (Coupled Model Intercomparision Project Phase 5). Specifically, a sudden decrease of soil moisture with a rate of -0.372 kg/m2/10a can be expected after ~2080 under RCP8.5 scenario. Amplifying terrestrial aridity due to increasing precipitation but more significant increasing potential evapotranspiration potentially results in drying HTP. Potential water deficiency for Asian rivers due to drying HTP should arouse considerable concerns.
Published in Science of Total Environment, https://doi.org/10.1016/j.scitotenv.2018.12.209.
