Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai‐Tibetan Plateau

Abstract

[1] Soil surface temperature is a critical boundary condition for the simulation of soil temperature by environmental models. It is influenced by atmospheric and soil conditions and by vegetation cover. In sophisticated land surface models, it is simulated iteratively by solving surface energy budget equations. In ecosystem, permafrost, and hydrology models, the consideration of soil surface temperature is generally simple. In this study, we developed a methodology for representing the effects of vegetation cover and atmospheric factors on the estimation of soil surface temperature for alpine grassland ecosystems on the QinghaiTibetan Plateau. Our approach integrated measurements from meteorological stations with simulations from a sophisticated land surface model to develop an equation set for estimating soil surface temperature. After implementing this equation set into an ecosystem model and evaluating the performance of the ecosystem model in simulating soil temperature at different depths in the soil profile, we applied the model to simulate interactions among vegetation cover, freeze-thaw cycles, and soil erosion to demonstrate potential applications made possible through the implementation of the methodology developed in this study. Results showed that (1) to properly estimate daily soil surface temperature, algorithms should use air temperature, downward solar radiation, and vegetation cover as independent variables; (2) the equation set developed in this study performed better than soil surface temperature algorithms used in other models; and (3) the ecosystem model performed well in simulating soil temperature throughout the soil profile using the equation set developed in this study. Our application of the model indicates that the representation in ecosystem models of the effects of vegetation cover on the simulation of soil thermal dynamics has the potential to substantially improve our understanding of the vulnerability of alpine grassland ecosystems to changes in climate and grazing regimes.Citation: Yi, S., N. Li, B. Xiang, X. Wang, B. Ye, and A. D. McGuire (2013), Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai-Tibetan Plateau,

Strong impacts of daily minimum temperature on the green‐up date and summer greenness of the Tibetan Plateau

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The unseen iceberg: plant roots in arctic tundra

“…The thaw depth of the active layer, which can range from a shallow 20 cm to > 1 m in thickness, changes seasonally and annually depending on the soil temperature at the end of winter, the air temperature during the growing season, soil insulation by organic soils or mosses, solar radiation, soil moisture and vegetation leaf area (e.g. Dennis & Johnson, ; van der Wal et al ., ; Ström et al ., ; Yi et al ., ).…”

Freeze/thaw processes in complex permafrost landscapes of northern Siberia simulated using the TEM ecosystem model: impact of thermokarst ponds and lakes

“…For snow, frozen soil and frozen water we assumed T surf = T air . A similar method has previously been used in Yi et al (2013).…”

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