A5006591200- Cryospheric studies and observations
- Climate change and permafrost
- Fire effects on ecosystems
- Arctic and Antarctic ice dynamics
- Landslides and related hazards
- Methane Hydrates and Related Phenomena
- Hydrology and Watershed Management Studies
- Plant Water Relations and Carbon Dynamics
- Groundwater flow and contamination studies
- Graphite, nuclear technology, radiation studies
- Nuclear and radioactivity studies
- CO2 Sequestration and Geologic Interactions
- Ecology and Vegetation Dynamics Studies
- Soil Moisture and Remote Sensing
- Winter Sports Injuries and Performance
- Forest ecology and management
- Geophysical and Geoelectrical Methods
- Hydraulic Fracturing and Reservoir Analysis
- Soil and Unsaturated Flow
- Fire dynamics and safety research
- Icing and De-icing Technologies
- Geophysical Methods and Applications
- Rangeland and Wildlife Management
- Radioactive contamination and transfer
- Soil erosion and sediment transport
Los Alamos National Laboratory
2015-2024
Environmental Earth Sciences
2021
United States Geological Survey
2014
Colorado School of Mines
2011-2013
Abstract A warmer climate increases evaporative demand. However, response to warming depends on water availability. Existing earth system models represent soil moisture but simplify groundwater connections, a primary control moisture. Here we apply an integrated surface-groundwater hydrologic model evaluate the sensitivity of shallow across majority US. We show that as shifts balance between supply and demand, storage can buffer plant stress; only where connections are present, not...
Abstract The need to understand potential climate impacts and feedbacks in Arctic regions has prompted recent interest modeling of permafrost dynamics a warming climate. A new fine‐scale integrated surface/subsurface thermal hydrology capability is described demonstrated proof‐of‐concept simulations. combines surface energy balance model with recently developed three‐dimensional subsurface models for nonisothermal water flows snow distribution the microtopography. Surface are modeled using...
Through taliks—thawed zones extending through the entire permafrost layer—represent a critical type of heterogeneity that affects water redistribution and heat transport, especially in sloping landscapes. The formation taliks as part transition from continuous to discontinuous creates new hydrologic pathways connecting active layer sub-permafrost regions, with significant hydrological biogeochemical consequences. At hilly field sites southern Seward Peninsula, AK, patches deep snow tall...
Abstract. Climate change is profoundly transforming the carbon-rich Arctic tundra landscape, potentially moving it from a carbon sink to source by increasing thickness of soil that thaws on seasonal basis. However, modeling capability and precise parameterizations physical characteristics needed estimate projected active layer (ALT) are limited in Earth system models (ESMs). In particular, discrepancies spatial scale between field measurements challenge validation parameterization...
The distribution of fuels is recognised as a key driver wildland fire behaviour. However, our understanding how fuel density heterogeneity affects behaviour limited because the challenges associated with experiments that isolate from other factors. Advances in modelling and computational resources provide means to explore responses heterogeneity. Using an ensemble approach simulate coupled fire–atmosphere model, we systematically tested fidelity shape effective wind characteristics...
Abstract Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in rapidly changing Arctic, uncertainties their prediction persist. Here, we harmonize SEB observations across a network vegetated and glaciated sites at circumpolar scale (1994–2021). Our variance-partitioning analysis identifies vegetation type as an important predictor SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude...
Abstract As of 2023, the use prescribed fire to manage ecosystems accounts for more than 50% area burned annually across United States. Prescribed is carried out when meteorological conditions, including temperature, humidity, and wind speed are appropriate its safe effective application. However, changes in these variables associated with future climate change may impact opportunities conduct fire. In this study, we combine projections information on burning windows ecoregions contiguous...
Abstract Active layer thickness (ALT), the uppermost of soil that thaws on an annual basis, is a direct control amount organic carbon potentially available for decomposition and release to atmosphere as carbon‐rich Arctic permafrost soils thaw in warming climate. We investigate how key site characteristics affect ALT using integrated surface/subsurface thermal hydrology model. most sensitive followed by snow depth but relatively insensitive water landscape with other conditions held fixed....
Core Ideas Burn severity data informed a hydrologic model to assess water balance changes. Loss of vegetation and evapotranspiration exceeded impact increased runoff. High burn may cause drier site conditions due Change in acts at long timescales while runoff is event based. Forest fires have significant on hydrology, such as reduced infiltration rates leading flooding. However, post‐fire changes the competing response function are not well understood. Comparing pre‐ challenging because...
Abstract. The goal of this research is to constrain the influence ice wedge polygon microtopography on near-surface ground temperatures. Ice prone rapid deformation in a changing climate, and cracking depends thermal conditions at top permafrost; therefore, feedbacks between temperature can shed light potential for future Arctic. We first report year sub-daily observations 5 depths 9 locations throughout cluster low-centered polygons near Prudhoe Bay, Alaska, demonstrate that rims become...
Abstract. The effects of soil property uncertainties on permafrost thaw projections are studied using a three-phase subsurface thermal hydrology model and calibration-constrained uncertainty analysis. null-space Monte Carlo method is used to identify hydrothermal parameter combinations that consistent with borehole temperature measurements at the study site, Barrow Environmental Observatory. Each combination then in forward projection conditions for 21st century (from calendar year 2006...
Abstract In the past three decades, an abrupt, pan‐Arctic acceleration of ice wedge melting has transformed tundra landscapes, spurring formation hummock‐like features known as high‐centered polygons (HCPs). This rapid geomorphic transition profoundly alters regional hydrology and influences surface emissions CO 2 CH 4 . Arctic Alaska, most recent instances degradation have arrested within 15–20 years inception, stabilizing HCP microtopography. However, feedbacks between ground deformation...
Abstract The Colorado River Basin is a fundamentally important river for society, ecology, and energy in the United States. Streamflow estimates are often provided using modeling tools which rely on uncertain parameters; sensitivity analysis can help determine parameters impact model results. Despite fact that simulated flows respond to changing climate vegetation basin, parameter of simulations under change has rarely been considered. In this study, we conduct global relate changes runoff,...
Abstract. We present a workflow for the rapid delineation and microtopographic characterization of ice wedge polygons within high-resolution digital elevation models. At core is convolutional neural network used to detect pixels representing polygon boundaries. A watershed transformation subsequently segment imagery into discrete polygons. Fast training times (<5 min) permit an iterative approach improving skill as routine applied across broad landscapes. Results from study sites near...
Background: Fire modeling is a key prescribed fire planning tool, but there are limited operational tools for integrating current models of forest change and behavior.AimsWe sought to integrate widely used succession model, LANDIS-II, with powerful behavior QUIC-Fire, into flexible workflow assessing in projected future fuel conditions. MethodsUsing aboveground biomass, we matched LANDIS-II data cohorts trees Forest Inventory Analysis (FIA) by predicting tree age across all FIA using Random...
Increased human health risk associated with groundwater contamination from potential carbon dioxide (CO2) leakage into a potable aquifer is predicted by conducting joint uncertainty and variability (JUV) assessment. The approach presented here explicitly incorporates heterogeneous flow geochemical reactive transport in an efficient manner used to evaluate how differences representation of subsurface physical heterogeneity reactions change the calculated for same hypothetical scenario where...
Abstract. Climate change is profoundly transforming the carbon-rich Arctic tundra landscape, potentially moving it from a carbon sink to source by increasing thickness of soil that thaws on seasonal basis. However, modeling capability and precise parameterizations physical characteristics needed estimate projected active layer (ALT) are limited in Earth System Models (ESMs). In particular, discrepancies spatial scale between field measurements challenge validation parameterization...
Abstract. Studies indicate greenhouse gas emissions following permafrost thaw will amplify current rates of atmospheric warming, a process referred to as the carbon feedback. However, large uncertainties exist regarding timing and magnitude feedback, in part due associated with subsurface parameterization structure. Development robust parameter estimation methods for permafrost-rich soils is becoming urgent under accelerated warming Arctic. Improved properties land system models would lead...
Heterogeneity in surface fuels produced by overstory trees and understory vegetation is a major driver of fire behavior ecosystem dynamics. Previous attempts at predicting tree leaf needle litter accumulation over time have been constrained scope to probabilistic models that consider limited number key factors influencing dispersal patterns decomposition processes. We present mechanistic model for estimating variation called the Distribution Understory using Elliptical Transport (DUET). DUET...