Improved Performance of CLM5.0 Model in Frozen Soil Simulation Over Tibetan Plateau by Implementing the Vegetation Emissivity and Gravel Hydrothermal Schemes

Luo, Jiangxin; Huang, Anning; Lyu, Shihua; Lin, Zhaohui; Gu, Chunlei; Li, Zhaoguo; Deng, Mingshan; Wen, Zhenhua; W, Liu

doi:10.1029/2022jd038021

Cited by 4 publications

(4 citation statements)

References 91 publications

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“…Winter biases likely occurred due to the development of a deeper early season snowpack in moist and wet meadow communities in CLM compared to observations (Figures 2a and 2b, and S2 in Supporting Information ). Work at other sites suggests that snow thermal conductivity in CLM5 is too high, resulting in cold wintertime soil temperature biases (Dutch et al., 2022; Luo et al., 2023). Preliminary results from our simulations at Niwot Ridge, however, suggest that thermal conductance of snow may be too low, resulting in warm winter soil temperature biases in moist and wet meadow columns.…”

Section: Resultsmentioning

confidence: 99%

“…Broadly, our findings underscore the challenges of representing biophysical and biogeochemical processes in sophisticated land models with high dimensionality parameter space (Dagon et al., 2020). For example, the generalized pedotransfer functions that are used in global scale, coarse resolution climate simulations with CLM may need more careful evaluation for local application in ecosystem‐scale studies (Dai et al., 2019; Luo et al., 2023). Such detailed measurements of soil thermal and hydraulic properties, however, are not commonly collected in sites with co‐located measurements of plant traits (for model parameterization) and long‐term measurements of ecosystem fluxes (for model calibration and evaluation).…”

Section: Resultsmentioning

confidence: 99%

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Topographic Heterogeneity and Aspect Moderate Exposure to Climate Change Across an Alpine Tundra Hillslope

Jay,

Wieder,

Swenson

et al. 2023

JGR Biogeosciences

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Alpine tundra ecosystems are highly vulnerable to climate warming but are governed by local‐scale abiotic heterogeneity, which makes it difficult to predict tundra responses to environmental change. Although land models are typically implemented at global scales, they can be applied at local scales to address process‐based ecological questions. In this study, we ran ecosystem‐scale Community Land Model (CLM) simulations with a novel hillslope hydrology configuration to represent topographically heterogeneous alpine tundra vegetation across a moisture gradient at Niwot Ridge, Colorado, USA. We used local observations to evaluate our simulations and investigated the role of topography and aspect in mediating patterns of snow, productivity, soil moisture, and soil temperature, as well as the potential exposure to climate change across an alpine tundra hillslope. Overall, our simulations captured observed gradients in abiotic conditions and productivity among heterogeneous, hydrologically connected vegetation communities (moist, wet, and dry). We found that south facing aspects were characterized by reduced snowpack and drier and warmer soils in all communities. When we extended our simulations to the year 2100, we found that earlier snowmelt altered the timing of runoff, with cascading effects on soil moisture, productivity, and growing season length. However, these effects were not distributed equally across the tundra, highlighting potential vulnerabilities of alpine vegetation in dry, wind‐scoured, and south facing areas. Overall, our results demonstrate how land model outputs can be applied to advance process‐based understanding of climate change impacts on ecosystem function.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Topographic Heterogeneity and Aspect Moderate Exposure to Climate Change Across an Alpine Tundra Hillslope

Jay,

Wieder,

Swenson

et al. 2023

JGR Biogeosciences

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“…The current version of Noah‐MP selectively estimates the soil hydraulic properties by partly adopting scheme of Saxton and Rawls (2006), which uses soil texture and organic matter, while the calculations of soil thermal properties only depend on soil texture. Nevertheless, studies (e.g., Liu et al., 2021; Luo et al., 2023; Luo, Lü, & Zhang, 2009; Luo, Lyu, et al., 2009; Sun et al., 2021; Zheng et al., 2015) suggested that influences of organic matter and gravel in soil hydraulic and thermal properties cannot be overlooked, especially when soil is frozen, soil with gravel has higher thermal conductivity and lower hydraulic conductivity (He et al., 2017; Peck & Watson, 1979). Organic matter and gravel widely distribute over high latitude and altitude regions (Lawrence & Slater, 2008; Shangguan et al., 2014), which should be important for calculations of soil hydraulic and thermal properties.…”

Section: Methodsmentioning

confidence: 99%

“…The detail can be referred to Table 1 in the paper by Saxton and Rawls (2006). It is worth noted that, distinguished from the incorporation into CLM (e.g., Liu et al., 2021; Luo et al., 2023), under the framework of Saxton and Rawls (2006) scheme, influences of gravel on soil porosity and matric potential cannot be directly considered, nevertheless, it can be indirectly achieved through feedback of k sat .…”

Section: Methodsmentioning

confidence: 99%

Optimization and Validation of Soil Frozen‐Thawing Parameterizations in Noah‐MP

Yang,

Zhaoye

et al. 2023

JGR Atmospheres

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Water‐heat transport in frozen soil influences the energy and water exchanges between land and atmosphere. However, frozen soil water‐heat transport simulation biases remaining in land surface model (LSM) result in uncertainties of climate model performance. In this study, the biases of the Noah with multi‐parameterization (Noah‐MP) land surface model in simulating soil water‐heat transport in freeze‐thaw (FT) process were investigated. On this basis, three parameterizations that were effective in other LSMs were implemented into Noah‐MP to optimize its performance. The results show that Noah‐MP still exhibits biases in simulating soil temperature and moisture in FT process. Even with various combinations of current parametrizations, the soil water–heat coupling relationship simulated by Noah‐MP does not align with observations. Nevertheless, the implementation of a virtual temperature parameterization, a liquid water‐dependent soil permeability parameterization, and modifications to soil hydraulic and thermal properties through considering the influences of organic matter and gravel, led to improvements in soil moisture and temperature simulations during both completely frozen and thawing periods. These enhancements resulted in a reduction of bias by approximately 20%–50%, and the simulated soil water–heat coupling relationship with implemented parameterizations closely matches observations. Global simulations further validate the improvements brought about by the implemented frozen‐thawing parameterizations in Noah‐MP.

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Negative impacts of the withered grass stems on winter snow cover over the Tibetan Plateau

Qi,

Yang,

et al. 2024

Agricultural and Forest Meteorology

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Improved Performance of CLM5.0 Model in Frozen Soil Simulation Over Tibetan Plateau by Implementing the Vegetation Emissivity and Gravel Hydrothermal Schemes

Abstract: The land surface process plays a critical role in land-air mass and energy exchanges, which greatly affects the weather and climate at local and regional scales (

Cited by 4 publications

References 91 publications

Topographic Heterogeneity and Aspect Moderate Exposure to Climate Change Across an Alpine Tundra Hillslope

Topographic Heterogeneity and Aspect Moderate Exposure to Climate Change Across an Alpine Tundra Hillslope

Optimization and Validation of Soil Frozen‐Thawing Parameterizations in Noah‐MP

Negative impacts of the withered grass stems on winter snow cover over the Tibetan Plateau

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