Quantitative assessment of the effects of climate, vegetation, soil and groundwater on soil moisture spatiotemporal variability in the Mongolian Plateau

Fanhao Meng; Min Luo; Chula Sa; Mulan Wang; Yuhai Bao

doi:10.1016/j.scitotenv.2021.152198

Quantitative assessment of the effects of climate, vegetation, soil and groundwater on soil moisture spatiotemporal variability in the Mongolian Plateau

Sci Total Environ. 2022 Feb 25:809:152198. doi: 10.1016/j.scitotenv.2021.152198. Epub 2021 Dec 7.

Authors

Fanhao Meng¹, Min Luo², Chula Sa¹, Mulan Wang¹, Yuhai Bao¹

Affiliations

¹ College of Geographical Science, Inner Mongolia Normal University, Hohhot 010022, China; Inner Mongolia Key Laboratory of Remote Sensing and Geographic Information Systems, Inner Mongolia Normal University, Hohhot 010022, China.
² College of Geographical Science, Inner Mongolia Normal University, Hohhot 010022, China; Inner Mongolia Key Laboratory of Remote Sensing and Geographic Information Systems, Inner Mongolia Normal University, Hohhot 010022, China. Electronic address: luomin@imnu.edu.cn.

PMID: 34890667
DOI: 10.1016/j.scitotenv.2021.152198

Abstract

Soil moisture (SM) is a key parameter regulating the hydrothermal balance of global terrestrial ecosystems and plays an important role in local ecological environment, particularly in arid and semiarid areas. However, current studies have so far obtained insufficient knowledge of SM spatiotemporal variability and its primary control factors, which limits our understanding of the feedback effects of SM on surface vegetation and hydrothermal activity. Here, we chose the ecologically fragile Mongolian Plateau (MP) as the study area to quantitatively reveal the soil moisture spatiotemporal variability (SMSTV) and the influence of control factors (climate, vegetation, soil and groundwater) with the help of empirical orthogonal functions (EOFs) and geographical detector models. The results indicated that a significant trend of decreasing SM and one dominant spatial structure (EOF1) of SM was found in the MP from 1982 to 2019, which explained over 54% of the spatial variability in SM, and as the soil depth increased, the EOF1 interpretation capacity increased. In addition, EOF1 is high in the north and east and low in the south and west of the MP and that vegetation cover is also relatively greater in the high-value areas. Overall, groundwater has the greatest influence on SMSTV in the MP (q = 0.89); however, precipitation and potential evapotranspiration remain the main control factors for SMSTV for different ecological zones, while the influence of vegetation elements (NDVI and GPP) cannot be ignored, and soil textures (clay, sand, silt) have the least influence. Meanwhile, SMSTV is explained to a greater extent by the interaction of the factors rather than by a single factor. However, there are differences in the influence mechanisms of each factor on SMSTV. This study provides strong evidence that meteorological forcing is not the only factor that dominates SMSTV and that the dominant factors may vary considerably between ecological zones.

Keywords: Climate; Groundwater; Mongolian Plateau; Soil moisture; Soil texture; Vegetation.

MeSH terms

Climate
Climate Change
Ecosystem
Groundwater*
Soil*

Substances

Soil