scholarly journals Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

2018 ◽  
Author(s):  
Michael M. Loranty ◽  
Benjamin W. Abbott ◽  
Daan Blok ◽  
Thomas A. Douglas ◽  
Howard E. Epstein ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Thermal Properties ◽  
Surface Energy ◽  
Terrestrial Ecosystem ◽  
Energy Partitioning ◽  
Climate Feedback ◽  
Permafrost Soil ◽  
Thermal Dynamics ◽  
Soil Thermal Properties ◽  
Permafrost Soils

Abstract. Permafrost soils in arctic and boreal ecosystems store twice the amount of current atmospheric carbon that may be mobilized and released to the atmosphere as greenhouse gases when soils thaw under a warming climate. This permafrost carbon climate feedback is among the most globally important terrestrial biosphere feedbacks to climate warming, yet its magnitude remains highly uncertain. This uncertainty lies in predicting the rates and spatial extent of permafrost thaw and subsequent carbon cycle processes. Terrestrial ecosystem influences on surface energy partitioning exert strong control on permafrost soil thermal dynamics and are critical for understanding permafrost soil responses to climate change and disturbance. Here we review how arctic and boreal ecosystem processes influence permafrost soils and characterize key ecosystem changes that regulate permafrost responses to climate. While many of the ecosystem characteristics and processes affecting soil thermal dynamics have been examined in isolation, interactions between processes are less well understood. In particular connections between vegetation, soil moisture, and soil thermal properties affecting permafrost conditions could benefit from additional research. In particular, connections between vegetation, soil moisture, and soil thermal properties affecting permafrost could benefit from additional research. Changes in ecosystem distribution and vegetation characteristics will alter spatial patterns of interactions between climate and permafrost. In addition to shrub expansion, other vegetation responses to changes in climate and disturbance regimes will all affect ecosystem surface energy partitioning in ways that are important for permafrost. Lastly, changes in vegetation and ecosystem distribution will lead to regional and global biophysical and biogeochemical climate feedbacks that may compound or offset local impacts on permafrost soils. Consequently, accurate prediction of the permafrost carbon climate feedback will require detailed understanding of changes in terrestrial ecosystem distribution and function and the net effects of multiple feedback processes operating across scales in space and time.

scholarly journals Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

2018 ◽  
Vol 15 (17) ◽  
pp. 5287-5313 ◽  
Author(s):  
Michael M. Loranty ◽  
Benjamin W. Abbott ◽  
Daan Blok ◽  
Thomas A. Douglas ◽  
Howard E. Epstein ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Energy ◽  
High Latitude ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Energy Partitioning ◽  
Climate Feedback ◽  
Permafrost Soil ◽  
Thermal Dynamics ◽  
Northern High Latitude

Abstract. Soils in Arctic and boreal ecosystems store twice as much carbon as the atmosphere, a portion of which may be released as high-latitude soils warm. Some of the uncertainty in the timing and magnitude of the permafrost–climate feedback stems from complex interactions between ecosystem properties and soil thermal dynamics. Terrestrial ecosystems fundamentally regulate the response of permafrost to climate change by influencing surface energy partitioning and the thermal properties of soil itself. Here we review how Arctic and boreal ecosystem processes influence thermal dynamics in permafrost soil and how these linkages may evolve in response to climate change. While many of the ecosystem characteristics and processes affecting soil thermal dynamics have been examined individually (e.g., vegetation, soil moisture, and soil structure), interactions among these processes are less understood. Changes in ecosystem type and vegetation characteristics will alter spatial patterns of interactions between climate and permafrost. In addition to shrub expansion, other vegetation responses to changes in climate and rapidly changing disturbance regimes will affect ecosystem surface energy partitioning in ways that are important for permafrost. Lastly, changes in vegetation and ecosystem distribution will lead to regional and global biophysical and biogeochemical climate feedbacks that may compound or offset local impacts on permafrost soils. Consequently, accurate prediction of the permafrost carbon climate feedback will require detailed understanding of changes in terrestrial ecosystem distribution and function, which depend on the net effects of multiple feedback processes operating across scales in space and time.

scholarly journals The improvement of soil thermodynamics and its effects on land surface meteorology in the IPSL climate model

2016 ◽  
Vol 9 (1) ◽  
pp. 363-381 ◽  
Author(s):  
F. Wang ◽  
F. Cheruy ◽  
J.-L. Dufresne
Keyword(s):  
Soil Moisture ◽  
Thermal Properties ◽  
Surface Energy ◽  
Surface Temperature ◽  
Energy Budget ◽  
Land Surface ◽  
Climate Model ◽  
Surface Energy Budget ◽  
Dry Areas ◽  
Soil Thermal Properties

Abstract. This paper describes the implementation of an improved soil thermodynamics in the hydrological module of Earth system model (ESM) developed at the Institut Pierre Simon Laplace (IPSL) and its effects on land surface meteorology in the IPSL climate model. A common vertical discretization scheme for the soil moisture and for the soil temperature is adopted. In addition to the heat conduction process, the heat transported by liquid water into the soil is modeled. The thermal conductivity and the heat capacity are parameterized as a function of the soil moisture and the texture. Preliminary tests are performed in an idealized 1-D (one-dimensional) framework and the full model is then evaluated in the coupled land–atmospheric module of the IPSL ESM. A nudging approach is used in order to avoid the time-consuming long-term simulations required to account for the natural variability of the climate. Thanks to this nudging approach, the effects of the modified parameterizations can be modeled. The dependence of the soil thermal properties on moisture and texture lead to the most significant changes in the surface energy budget and in the surface temperature, with the strongest effects on the surface energy budget taking place over dry areas and during the night. This has important consequences on the mean surface temperature over dry areas and during the night and on its short-term variability. The parameterization of the soil thermal properties could therefore explain some of the temperature biases and part of the dispersion over dry areas in simulations of extreme events such as heat waves in state-of-the-art climate models.

scholarly journals The improvement of soil thermodynamics and its effects on land surface meteorology in the IPSL climate model

2015 ◽  
Vol 8 (10) ◽  
pp. 8411-8450
Author(s):  
F. Wang ◽  
F. Cheruy ◽  
J.-L. Dufresne
Keyword(s):  
Soil Moisture ◽  
Thermal Properties ◽  
Surface Energy ◽  
Surface Temperature ◽  
Energy Budget ◽  
Land Surface ◽  
Climate Model ◽  
Surface Energy Budget ◽  
Dry Areas ◽  
Soil Thermal Properties

Abstract. This paper describes the implementation of an improved soil thermodynamics in the hydrological module of Earth System Model (ESM) developed at the Institut Pierre Simon Laplace (IPSL) and its effects on land surface meteorology in the IPSL climate model. A common vertical discretization scheme for the soil moisture and for the soil temperature is adopted. In addition to the heat conduction process, the heat transported by liquid water into the soil is modeled. The thermal conductivity and the heat capacity are parameterized as a function of the soil moisture and the texture. Preliminary tests are performed in an idealized 1-D framework and the full model is then evaluated in the coupled land/atmospheric module of the IPSL ESM. A nudging approach is used in order to avoid the time-consuming long-term simulations required to account for the natural variability of the climate. Thanks to this nudging approach, the effects of the modified parameterizations can be modeled. The dependence of the soil thermal properties on moisture and texture lead to the most significant changes in the surface energy budget and in the surface temperature, with the strongest effects on the surface energy budget taking place over dry areas and during the night. This has important consequences on the mean surface temperature over dry areas and during the night and on its short-term variability. The parameterization of the soil thermal properties could therefore explain some of the temperature biases and part of the dispersion over dry areas in simulations of extreme events such as heat waves in state-of-the-art climate models.

scholarly journals Satellite‐Based Assessment of Land Surface Energy Partitioning–Soil Moisture Relationships and Effects of Confounding Variables

2019 ◽  
Vol 55 (12) ◽  
pp. 10657-10677 ◽  
Author(s):  
Andrew F. Feldman ◽  
Daniel J. Short Gianotti ◽  
Isabel F. Trigo ◽  
Guido D. Salvucci ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Surface Energy ◽  
Land Surface ◽  
Energy Partitioning ◽  
Confounding Variables

scholarly journals A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback

2015 ◽  
Vol 373 (2054) ◽  
pp. 20140423 ◽  
Author(s):  
C. D. Koven ◽  
E. A. G. Schuur ◽  
C. Schädel ◽  
T. J. Bohn ◽  
E. J. Burke ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Climate Feedback ◽  
Soil Horizon ◽  
Future Climate Change ◽  
Thermal Dynamics ◽  
Soil C ◽  
Warming Scenario ◽  
C Stocks ◽  
Permafrost Soils

We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation–Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2–33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9–112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change ( γ sensitivity) of −14 to −19 Pg C °C −1 on a 100 year time scale. For CH 4 emissions, our approach assumes a fixed saturated area and that increases in CH 4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH 4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10–18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming.

scholarly journals Intercomparison of the Surface Energy Partitioning in CMIP5 Simulations

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 602 ◽  
Author(s):  
Yang ◽  
Wang ◽  
Huang
Keyword(s):  
Soil Moisture ◽  
Surface Energy ◽  
Land Surface ◽  
Radiative Forcing ◽  
Climate Models ◽  
Water Cycle ◽  
Potential Evapotranspiration ◽  
Sensible Heat Flux ◽  
Coupled Model ◽  
Energy Partitioning

The warming climate significantly modifies the global water cycle. Global evapotranspiration has increased over the past decades, yet climate models agree on the drying trend of land surface. In this study, we conducted an intercomparison analysis of the surface energy partitioning across Coupled Model Intercomparison Phase 5 (CMIP5) simulations and evaluated its behaviour with surface temperature and soil moisture anomalies, against the theoretically derived thermodynamic formula. Different responses over land and sea surfaces to elevated greenhouse gas emissions were found. Under the Representative Concentration Pathway of +8.5 W m−2 (RCP8.5) warming scenario, the multi-model mean relative efficiency anomaly from CMIP5 simulations is 3.83 and −0.12 over global sea and land, respectively. The significant anomaly over sea was captured by the thermodynamic solution based on the principle of maximum entropy production, with a mean relative error of 14.6%. The declining trend over land was also reproduced, but an accurate prediction of its small anomaly will require the inclusions of complex physical processes in future work. Despite increased potential evapotranspiration under rising temperatures, both CMIP5 simulations and thermodynamic principles suggest that the soil moisture-temperature feedback cannot support long-term enhanced evapotranspiration at the global scale. The dissipation of radiative forcing eventually shifts towards sensible heat flux and accelerates the warming over land, especially over South America and Europe.

High-resolution temperature observations to monitor soil thermal properties as a proxy for soil moisture condition in clay-shale landslide

2011 ◽  
Vol 26 (14) ◽  
pp. 2143-2156 ◽  
Author(s):  
Dominika M. Krzeminska ◽  
Susan C. Steele-Dunne ◽  
Thom A. Bogaard ◽  
Martine M. Rutten ◽  
Pascal Sailhac ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Thermal Properties ◽  
High Resolution ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Clay Shale ◽  
Soil Thermal Properties ◽  
Temperature Observations

scholarly journals Effects of Summer Rainfall on the Soil Thermal Properties and Surface Energy Balances in the Badain Jaran Desert

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jiangang Li ◽  
Ali Mamtimin ◽  
Zhaoguo Li ◽  
Cailian Jiang ◽  
Minzhong Wang
Keyword(s):  
Thermal Properties ◽  
Surface Energy ◽  
Soil Temperature ◽  
Numerical Models ◽  
Surface Energy Budget ◽  
Surface Radiation ◽  
Badain Jaran Desert ◽  
Short Term ◽  
Soil Thermal Properties ◽  
Energy Balances

Based on observational data collected during the summer of 2009 from the southern Badain Jaran Desert, the surface sensible and latent heat fluxes and shallow soil thermal storage were obtained through corrections and quality control measures. The soil thermal properties and characteristics of the land surface energy budget before and after rainfall episodes were systematically analyzed. Short-term precipitation had a greater influence than systematic precipitation on the soil temperature (ST) and soil volumetric water content (VWC). After rainfall, the VWC rapidly increased, showing a decreasing growth rate trend with depth and time in all layers; the soil temperature change rate (TCR) exhibited the opposite tendency. The surface albedo, which was affected little by the solar elevation angle and short-term precipitation, fluctuated from low to high during short-term rainfall. The soil thermal parameters, including the volumetric heat capacity, thermal conductivity, and diffusivity, all increased after rainfall. The diurnal soil heat flux variations in each layer manifested as quasisinusoids, and the amplitude gradually decreased with depth. The energy balance ratio (EBR) without and with soil heat storage (S) varied differently; after incorporating S, the EBR increased by approximately 5-6% regardless of rainfall but remained lower afterward. Throughout the observation period, the maximum daytime EBR appeared approximately 1-2 days before or after rainfall and gradually declined otherwise. These findings are fundamental for understanding the influences of cloud and precipitation disturbances on radiation budgets and energy distributions and improving the parameterization of surface radiation budgets and energy balances for numerical models of semiarid areas.

scholarly journals Reducing soil moisture measurement scale mismatch to improve surface energy flux estimation

2016 ◽  
Author(s):  
Joost Iwema ◽  
Rafael Rosolem ◽  
Mostaquimur Rahman ◽  
Eleanor Blyth ◽  
Thorsten Wagener
Keyword(s):  
Soil Moisture ◽  
Surface Energy ◽  
Energy Flux ◽  
Spatial Scales ◽  
Cosmic Ray ◽  
Energy Partitioning ◽  
Surface Model ◽  
Surface Energy Flux ◽  
Soil Moisture Data ◽  
Scale Mismatch

Abstract. At the so-called hyper-resolution scale (i.e. grid cells of 1 km2) Land Surface Model (LSM) parameters are sometimes calibrated with Eddy-Covariance (EC) data and Point Scale (PS) soil moisture data. However, measurement scales of EC and PS data differ substantially. In our study, we investigated the impact of reducing the scale mismatch between surface energy flux data and soil moisture data by replacing PS soil moisture data with observations derived from Cosmic-Ray Neutron Sensors (CRNS) made at larger spatial scales. Five soil-evapotranspiration parameters of the Joint UK Land Environment Simulator (JULES) were calibrated against PS and CRNS soil moisture data separately. We calibrated the model for twelve sites in the USA representing a range of climatic, soil, and vegetation conditions. The improvement in surface energy partitioning for the two calibration solutions was assessed by comparing to EC data and to a version of JULES runs with default parameter values. We found that simulated surface energy partitioning did not differ substantially between the PS and CRNS calibrations, despite their differences in actual soil moisture observations. We concluded that potential differences due to distinct spatial scales represented by the PS and CRNS soil moisture sensor techniques were substantially undermined by the weak coupling between soil moisture and evapotranspiration within JULES.

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