Variations in Soil Water Content and Evapotranspiration in Relation to Precipitation Pulses within Desert Steppe in Inner Mongolia, China

Abstract

Neither single nor discontinuous hydrological observation data can truly reflect periodic changes in soil moisture under natural conditions or interrelationships between various water sources. Therefore, in this study, precipitation pulse characteristics and variations in the soil water content (SWC) and actual evapotranspiration (ETa) in relation to pulses are explored through a field multi-water continuous observation system set in desert steppe in Inner Mongolia, China. A comparison between precipitation events in the growing seasons of 2016 and 2017 shows that precipitation events that are greater than 10 mm are the main cause of dramatic interannual precipitation variations in this region. A single small precipitation event has a limited impact on SWC and provides no obvious increase in the SWC within the top 10 cm soil layer. The precipitation interval ratio (P/I) is suitable for comparing water stresses of different drying-wetting cycles, and correlations between soil layers are found to be closer in humid years than in dry years. In this study, three modes of interpulse ETa in the desert steppe are discussed: a stable ETa mode under a water-sufficient condition, an attenuation ETa mode, and a stable ETa mode under extreme drought conditions.

Comparison of high spatiotemporal‐resolution soil moisture observations with CLM4.0 simulations

“…In addition, soil moisture may affect the atmospheric condition by directly influencing evaporation and latent heat (Mahrt and Ek, 1984), and soil moisture can also affect the prediction of a forecast model for two to three weeks or more (Walker and Rowntree, 1977). Therefore, it is of great significance to use soil moisture data properly a the land-surface model and to understand the mechanisms underlying the interaction between soil moisture and the atmosphere (Pan and Mahrt, 1987;Chen et al, 1997;Gaertner et al, 2010;Seneviratne et al, 2010;Vereecken et al, 2014;Li et al, 2019;Shi et al, 2019;Song et al, 2019).…”

Precipitation regulates the livestock dung seed bank through above ground vegetation productivity in the Qaidam basin

“…Precipitation is the most important factor limiting grassland production in arid regions (Song et al, 2019). We found that, with an increase in precipitation, the abundance, density, biomass, diversity and seed yield of the AGV increased significantly.…”

“…In the context of global climate change, there will be fewer precipitation events in certain geographic regions yet larger per‐event rainfall volumes, and the frequency of extreme precipitation events will also increase globally (Intergovernmental Panel on Climate Change, 2013). Precipitation correlates positively with grassland productivity (Gamoun, 2016; Song et al, 2019). Changes in precipitation patterns can have a notable impact on the structure and species dynamics of grassland ecosystems, as precipitation is the main limiting factor of grassland productivity, especially in semiarid and arid regions (Noy‐Meir, 1973; Reynolds et al, 2004).…”

Feasibility Investigation of Improving the Modified Green–Ampt Model for Treatment of Horizontal Infiltration in Soil

“…x bi advancement distance of the intersection point between the transmission zone and the wetting zone (m) x ci advancement distance of the intersection point of two linear functions in the wetting zone (m) x i advancement distance of the WF (m) x T water advancement distance at the top of the PVC column (m) y [1][2][3][4] parameters that described relationship between T t and θ Greek letters…”

“…The unsaturated zone of the earth's surface is an important link between the atmosphere and deeper soil profiles. Water movement and its distribution within the unsaturated zone determine the physical and hydrological properties of the soil medium and its utility in many socio-economic activities such as environmental sustainability, geo-hazards management, stability of marine dike, and beach erosion [1][2][3][4]. The unsaturated ground surface is also the most important homeland for insects, and the activities of these insects are changing water infiltration model [5].…”