Environmental Science Division (EVS)a Division of Argonne National Laboratory
 

Soil Organic Carbon Storage and Dynamics of Permafrost Systems

EVS soil scientists are using several approaches to study the storage and dynamics of organic carbon of permafrost affected soils.

Because of their cold temperatures and multiple soil forming processes, permafrost affected soils store much of the organic carbon in terrestrial ecosystems. High-latitudes, where most permafrost affected soils are located, are projected to experience greater increases in temperature than other parts of the world. As a result of these anticipated temperature increases and the concomitant degradation of permafrost, permafrost affected soils are a vulnerable component of the global carbon cycle. EVS soil scientists are conducting a number of studies in the permafrost domain, using field observations, knowledge of soil-forming factors, and geospatial and process-based models to understand the storage and vulnerability of organic carbon of the permafrost affected soils.

Predicting Spatial and Vertical Distributions of Soil Organic Carbon

The spatial and vertical distributions of soil organic carbon (SOC) will determine the direction and magnitude of soil carbon changes in response to climate change. EVS soil scientists are estimating spatially resolved SOC stocks from surface to bedrock, distinguishing active-layer and permafrost-layer SOC stocks. EVS is also quantifying the spatial distribution of uncertainty estimates in observations, and in the environmental controllers of SOC stocks of permafrost affected soils that are critical to predicting the response of permafrost carbon to a changing climate.

Predicted SOC stocks across Alaska at 60-m spatial resolution
Predicted SOC stocks across Alaska at 60-m spatial resolution [Source: Argonne National Laboratory]

Quantifying Scaling Impacts on Spatial Heterogeneity and Environmental Controllers of Soil Organic Carbon

The spatial heterogeneity of land surfaces affects energy, moisture, and greenhouse gas exchanges with the atmosphere; however, representing this heterogeneity in Earth system models remains a critical scientific challenge. EVS soil scientists are studying the impact of spatial scaling on environmental controllers, spatial structure, and statistical properties of SOC across the state of Alaska. Understanding the scaling behavior of environmental controllers and statistical properties of SOC stocks will improve land model benchmarking and allow representation of spatial heterogeneity at scales finer than those currently resolved by Earth system models.

Scaling impacts environmental controllers, spatial structure and heterogeneity of soil organic carbon stocks
Scaling impacts environmental controllers, spatial structure and heterogeneity of soil organic carbon stocks [Source: Argonne National Laboratory]

Capturing the Spatial Heterogeneity of Soil Organic Carbon under Current and Future Climate Scenarios

Representing land surface spatial heterogeneity when designing observation networks is a critical scientific challenge. EVS soil scientists are developing geospatial approaches that utilize the multivariate spatial heterogeneity of soil-forming factors—namely, climate, topography, land cover types, and surficial geology—to identify new observation sites in Alaska that will reduce the uncertainty in SOC stock estimates and improve broad-scale mapping and model-benchmarking efforts there.

Distribution of observation sites at 2.5 kg C m<sup>-2</sup> (left) and 5 kg C m<sup>-2</sup> (right) margin of errors. Red dots represent locations within the spatial correlation length of existing samples and green dots represent observation sites where new samples need to be collected.
Distribution of observation sites at 2.5 kg C m-2 (left) and 5 kg C m-2 (right) margin of errors. Red dots represent locations within the spatial correlation length of existing samples and green dots represent observation sites where new samples need to be collected. [Source: Argonne National Laboratory]

Benchmarking Global Earth System Model Projections of Equilibrium State Soil Properties

Soil properties such as SOC stocks and active-layer thickness are used in Earth system models to predict anthropogenic and climatic impacts on soil carbon dynamics, as well as future changes in atmospheric greenhouse gas concentrations and associated climate changes in permafrost regions. Accurate representation of the spatial and vertical distribution of these soil properties in Earth system models is a prerequisite for reducing uncertainty in predicting carbon-climate feedbacks. EVS soil scientists are benchmarking the spatial representation of equilibrium SOC stocks and active-layer thicknesses predicted by the Coupled Model Intercomparison Project Phase 5 (CMIP5) Earth system models based on field observations and geospatial predictions.

Differences in SOC stocks (to 1-m depth) between baseline Earth system model estimates and observation-based data. Brown colors (positive values) show over-predictions, white shows tentative agreement, and blue colors (negative values) show under-predictions.
Differences in SOC stocks (to 1-m depth) between baseline Earth system model estimates and observation-based data. Brown colors (positive values) show over-predictions, white shows tentative agreement, and blue colors (negative values) show under-predictions. [Source: Argonne National Laboratory]

Related Research Areas

See the Research Highlights Index for a complete list of EVS Research Areas.

photo of Umakant Mishra
Geospatial Scientist
Capabilities: Digital soil prediction, spatial uncertainty estimation, terrain analysis, scaling, sampling, remote sensing, pedometrics.