Agreement of Analytical and Simulation‐Based Estimates of the Required Land Depth in Climate Models

Steinert, Norman Julius; González-Rouco, J. Fidel; Melo‐Aguilar, Camilo; Pereira, Francisco; García‐Bustamante, Elena; Vrese, Philipp de; Alexeev, V. A.; Jungclaus, Johann; Lorenz, Stephan; Hagemann, Stefan

doi:10.1029/2021gl094273

Cited by 9 publications

(11 citation statements)

References 42 publications

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“…The first setup equals the standard CMIP6 version of MPI‐ESM, which uses the JSBACH LSM (Reick et al., 2021) with five layers (9.83 m; SHALLOW hereafter). For the second setup, we introduce modifications to the vertical structure of JSBACH, which uses an extended 18‐layer discretization with a larger model depth (1,417 m; DEEP hereafter) that is well suited for the simulation of centennial to millennial timescales (González‐Rouco et al., 2021; Steinert et al., 2024; Steinert, González‐Rouco, de Vrese, et al., 2021; Steinert, González‐Rouco, Melo‐Aguilar, et al., 2021). The two simulations were prepared by restarting the ocean component MPIOM from an existing CMIP6 control simulation.…”

Section: Model Data and Methodologymentioning

confidence: 99%

“…These results represent an overestimation of the amount of ocean heat storage and an underestimation of heat uptake by the cryosphere and land components in comparison to the observational estimates (Cuesta‐Valero et al., 2021). Previous literature has suggested that land heat uptake under climate change conditions in ESMs is compromised by too shallow land surface model components (LSMs) because a subsurface bottom boundary condition too close to the surface biases the representation of subsurface heat propagation and heat distribution (Alexeev et al., 2007; Cuesta‐Valero et al., 2016, 2021; González‐Rouco et al., 2009, 2021; MacDougall et al., 2008; Smerdon & Stieglitz, 2006; Steinert et al., 2024; Steinert, González‐Rouco, de Vrese, et al., 2021; Steinert, González‐Rouco, Melo‐Aguilar, et al., 2021; Stevens et al., 2007). Despite recent improvements in modeling land processes in ESMs (Fisher & Koven, 2020), only limited attention has been directed toward the effect of land model depth and its impact on the representation of terrestrial thermodynamics.…”

Section: Introductionmentioning

confidence: 99%

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Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

Steinert,

Cuesta‐Valero,

García‐Pereira

et al. 2024

Geophysical Research Letters

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Current global warming results in an uptake of heat by the Earth system, which is distributed among the different components of the climate system. However, current‐generation climate models deliver heat inventory and partitioning estimates of Earth system components that differ from recent observations. Here we investigate the global heat distribution under warming by using fully‐coupled CMIP6 Earth system model experiments, including a version of the MPI‐ESM with a deep land model component, accommodating the required space for more realistic terrestrial heat storage. The results show that sufficiently deep land models exert increased subsurface land heat uptake, leading to a heat uptake partitioning among the Earth system components that is closer to observational estimates. The results are relevant for the understanding of Earth's heat partitioning and highlight the importance of the land heat sink in the Earth heat inventory.

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Section: Model Data and Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

Steinert,

Cuesta‐Valero,

García‐Pereira

et al. 2024

Geophysical Research Letters

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“…This is very different to the standard vertical setup which represents the soil column by 5 layers reaching to a depth of less than 10 m. Imposing a deeper bottom boundary is important for a realistic representation of the soil thermodynamic regime, with implications for subsurface heat conduction and energy distribution (MacDougall et al, 2008;González-Rouco et al, 2009;González-Rouco et al, 2021), as too shallow LSMs alter the distribution of temperatures in the subsurface (Alexeev et al, 2007;Smerdon and Stieglitz, 2006). As shown by Steinert et al (2021b) a depth > 150 m is required to resemble an infinitely deep soil in climate-change simulations of centennial timescales. The improved vertical resolution and bottom boundary condition depth used herein produce changes in the subsurface thermal state that have been shown to interact with the phase changes and other hydrological features.…”

Section: Simulationsmentioning

confidence: 96%

Representation of soil hydrology in permafrost regions may explain large part of inter-model spread in simulated Arctic and subarctic climate

Vrese

Georgievski²,

González-Rouco³

et al. 2022

Preprint

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Abstract. The current generation of Earth system models exhibits large inter-model differences in the simulated climate of the Arctic and subarctic zone, with differences in model structure and parametrizations being one of the main sources of uncertainty. One particularly challenging aspect in modelling is the representation of terrestrial processes in permafrost-affected regions, which are often governed by spatial heterogeneity far below the resolution of the models' land surface components. Here, we use the MPI Earth System model to investigate how different plausible assumptions for the representation of the permafrost hydrology modulate the land-atmosphere interactions and how the resulting feedbacks affect not only the regional and global climate, but also our ability to predict whether the high latitudes will become wetter or drier in a warmer future. Focusing on two idealized setups that induce comparatively "wet" or "dry" conditions in regions that are presently affected by permafrost, we find that the parameter settings determine the direction of the 21st-century trend in the simulated soil water content and result in substantial differences in the land-atmosphere exchange of energy and moisture. The latter leads to differences in the simulated cloud cover and thus in the planetary energy uptake. The respective effects are so pronounced that uncertainties in the representation of the Arctic hydrological cycle can help to explain a large fraction of the inter-model spread in regional surface temperatures and precipitation. Furthermore, they affect a range of components of the Earth system as far to the south as the tropics. With both setups being similarly plausible, our findings highlight the need for more observational constraints on the permafrost hydrology to reduce the inter-model spread in Arctic climate projections.

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Section: Simulationsmentioning

confidence: 97%

Representation of soil hydrology in permafrost regions may explain large part of inter-model spread in simulated Arctic and subarctic climate

Vrese

Georgievski

Rouco

et al. 2022

Preprint

View full text Add to dashboard Cite

The current generation of Earth system models exhibits large inter-model differences in the simulated climate of the Arctic and subarctic zone, with differences in model structure and parametrizations being one of the main sources of uncertainty. One particularly challenging aspect in modelling is the representation of terrestrial processes in permafrost-affected regions, which are often governed by spatial heterogeneity far below the resolution of the models' land surface components. Here, we use the MPI Earth System model to investigate how different plausible assumptions for the representation of the permafrost hydrology modulate the land-atmosphere interactions and how the resulting feedbacks affect not only the regional and global climate, but also our ability to predict whether the high latitudes will become wetter or drier in a warmer future. Focusing on two idealized setups that induce comparatively "wet" or "dry" conditions in regions that are presently affected by permafrost, we find that the parameter settings determine the direction of the 21stcentury trend in the simulated soil water content and result in substantial differences in the land-atmosphere exchange of energy and moisture. The latter leads to differences in the simulated cloud cover and thus in the planetary energy uptake. The respective effects are so pronounced that uncertainties in the representation of the Arctic hydrological cycle can help to explain a large fraction of the inter-model spread in regional surface temperatures and precipitation. Furthermore, they affect a range of components of the Earth system as far to the south as the tropics. With both setups being similarly plausible, our findings highlight the need for more observational constraints on the permafrost hydrology to reduce the inter-model spread in Arctic climate projections.

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Agreement of Analytical and Simulation‐Based Estimates of the Required Land Depth in Climate Models

Abstract: The thermal state of the ground governs heat and water exchanges, latent and sensible heat fluxes, plant growth rates, and soil organic matter decomposition and transport (e.g.,

Cited by 9 publications

References 42 publications

Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

Underestimated Land Heat Uptake Alters the Global Energy Distribution in CMIP6 Climate Models

Representation of soil hydrology in permafrost regions may explain large part of inter-model spread in simulated Arctic and subarctic climate

Representation of soil hydrology in permafrost regions may explain large part of inter-model spread in simulated Arctic and subarctic climate

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