Projected changes in soil freeze depth and their eco-hydrological impacts over the Tibetan Plateau during the 21st century

Hu Li; Xiaoduo Pan; Xiaoqing Peng; Rana Muhammad Ali Washakh; Min Zheng; Xiaowei Nie

doi:10.1016/j.scitotenv.2023.167074

Projected changes in soil freeze depth and their eco-hydrological impacts over the Tibetan Plateau during the 21st century

Sci Total Environ. 2023 Dec 20:905:167074. doi: 10.1016/j.scitotenv.2023.167074. Epub 2023 Sep 13.

Authors

Hu Li¹, Xiaoduo Pan², Xiaoqing Peng³, Rana Muhammad Ali Washakh⁴, Min Zheng⁵, Xiaowei Nie⁶

Affiliations

¹ National Tibetan Plateau Data Center (TPDC), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
² National Tibetan Plateau Data Center (TPDC), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810016, China. Electronic address: panxd@itpcas.ac.cn.
³ Key Laboratory of Western China's Environmental Systems, Ministry of Education, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: pengxq@lzu.edu.cn.
⁴ National Tibetan Plateau Data Center (TPDC), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; School of Civil Engineering, Guizhou Institute of Technology, Guiyang 550003, China.
⁵ Key Laboratory of Western China's Environmental Systems, Ministry of Education, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
⁶ National Tibetan Plateau Data Center (TPDC), State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China. Electronic address: xwnie@itpcas.ac.cn.

PMID: 37714360
DOI: 10.1016/j.scitotenv.2023.167074

Abstract

In the context of global warming, the soil freeze depth (SFD) over the Tibetan Plateau (TP) has undergone significant changes, with a series of profound impacts on the hydrological cycle and ecosystem. The complex terrains and high elevations of the TP pose great challenges in data acquisition, presenting difficulties for studying SFD in this region. This study employs Stefan's solution and downscaled datasets from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to simulate the future SFDs over the TP. The changing trends of the projected SFDs under different Shared Socio-economic Pathways (SSP) scenarios are investigated, and; the responses of SFDs to potential climatic factors, such as temperature and precipitation, are analyzed. The potential impacts of SFD changes on eco-hydrological processes are analyzed based on the relationships between SFDs, the distribution of frozen ground, soil moisture, and the Normalized Difference Vegetation Index (NDVI). Results show that the projected SFDs of the TP are estimated to decrease at rates of 0.100 cm/yr under the SSP126, 0.330 cm/yr under the SSP245, 0.565 cm/yr under the SSP370, and 0.750 cm/yr under the SSP585. Additionally, the SFD decreased at a rate of 0.160 cm/yr during the historical period from 1950 to 2014, which was between the decreasing rates of the SSP126 and SSP245 scenarios. The projected SFDs are negatively correlated with air temperature and precipitation, more significant under the higher emissions scenario. The projected decrease in SFDs will significantly impact eco-hydrological processes. A rapid decrease in SFD may lead to a decline in soil moisture content and have adverse impacts on vegetation growth. This research provides valuable insights into the future changes in SFD on the TP and their impacts on eco-hydrological processes.

Keywords: CMIP6; Frozen ground; Future climate change; Soil freeze depth; Stefan's solution; Tibetan plateau.