A5086354457- Climate change and permafrost
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Geological Studies and Exploration
- Indigenous Studies and Ecology
- Fire effects on ecosystems
- Rangeland and Wildlife Management
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Peatlands and Wetlands Ecology
- Arctic and Antarctic ice dynamics
- Scientific Research and Discoveries
- NMR spectroscopy and applications
- Ecology and Vegetation Dynamics Studies
- Vehicle emissions and performance
- Coastal wetland ecosystem dynamics
- Species Distribution and Climate Change
- Landslides and related hazards
- Remote Sensing in Agriculture
- Plant Water Relations and Carbon Dynamics
- Advanced MRI Techniques and Applications
- Tree-ring climate responses
- Arctic and Russian Policy Studies
- Advanced Neuroimaging Techniques and Applications
- Soil and Unsaturated Flow
United States Geological Survey
2014-2025
Earth Resources Observation and Science Center
2014-2025
University of Sioux Falls
2023
KBR (United States)
2020
Stinger Ghaffarian Technologies (United States)
2013-2018
Minnesota Department of Natural Resources
2015-2018
University of Minnesota
2015-2018
Ecological Society of America
2018
John Wiley & Sons (United States)
2018
University of Minnesota System
2017
Abstract Contemporary climate change in Alaska has resulted amplified rates of press and pulse disturbances that drive ecosystem with significant consequences for socio‐environmental systems. Despite the vulnerability Arctic boreal landscapes to change, little been done characterize landscape associated drivers across northern high‐latitude ecosystems. Here we historical sensitivity Alaska's ecosystems environmental anthropogenic using expert knowledge, remote sensing data, spatiotemporal...
Abstract Fire can be a significant driver of permafrost change in boreal landscapes, altering the availability soil carbon and nutrients that have important implications for future climate ecological succession. However, not all landscapes are equally susceptible to fire‐induced change. As fire frequency is expected increase high latitudes, methods understand vulnerability resilience different degradation needed. We present combination multiscale remote sensing, geophysical, field...
Invasive annual grasses, such as cheatgrass (Bromus tectorum L.), have proliferated in dryland ecosystems of the western United States, promoting increased fire activity and reduced biodiversity that can be detrimental to socio-environmental systems. Monitoring exotic grass cover dynamics over large areas requires use remote sensing support early detection rapid response initiatives. However, few studies leveraged technologies computing frameworks capable providing rangeland managers with...
Abstract Methane (CH 4 ) emissions from climate‐sensitive ecosystems within the northern permafrost region represent a potentially large but highly uncertain source, with current estimates spanning factor of seven (11–75 Tg CH yr −1 ). Accelerating thaw threatens significant increases in pan‐Arctic emissions, amplifying carbon feedback. We used airborne imaging spectroscopy meter‐scale spatial resolution and broad coverage to identify previously undiscovered emission hotspot adjacent...
Abstract Climate change is thawing and potentially mobilizing vast quantities of organic carbon (OC) previously stored for millennia in permafrost soils northern circumpolar landscapes. Climate‐driven increases fire thermokarst may play a key role OC mobilization by promoting transport OC. Yet, the extent mechanisms controlling terrestrial‐aquatic transfer are unclear. We demonstrate that hydrologic soil dissolved (DOC) from active layer to headwater streams extremely heterogeneous regulated...
Abstract Complex nonlinear relationships exist between the permafrost thermal state, active layer thickness, and terrestrial carbon cycle dynamics. In Arctic boreal Alaska, significant uncertainties characterize spatiotemporal rate magnitude of degradation feedback, with increasing recognition importance thawing mechanisms. The challenges monitoring sub‐surface phenomena remote sensing technology further complicate issue. There is an urgent need to understand how what extent destabilizes...
Modern climate change in Alaska has resulted widespread thawing of permafrost, increased fire activity, and extensive changes vegetation characteristics that have significant consequences for socioecological systems. Despite observations the heightened sensitivity these systems to change, there not been a comprehensive assessment factors drive ecosystem throughout Alaska. Here we present research improves our understanding main drivers spatiotemporal patterns carbon dynamics using situ...
Abstract Thermokarst lakes accelerate deep permafrost thaw and the mobilization of previously frozen soil organic carbon. This leads to microbial decomposition large releases carbon dioxide (CO 2 ) methane (CH 4 that enhance climate warming. However, time scale permafrost-carbon emissions following is not well known but important for understanding how abrupt impacts feedback. We combined field measurements radiocarbon dating CH ebullition with (a) an assessment lake area changes delineated...
Abstract Exotic annual grasses (EAG) are one of the most damaging agents change in western North America. Despite known socio‐environmental effects EAG there remains a need to enhance monitoring capabilities for better informing conservation and management practices. Here, we integrate field observations, remote sensing climate data with machine‐learning techniques estimate assess patterns historical (1985–2019; R 2 = 0.86 ± 0.05; MAE 6.7 1.4%), present (2020), future (2025–2040) abundance...
The invasion of exotic annual grass (EAG), e.g., cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae), into rangeland ecosystems the western United States is a broad-scale problem that affects wildlife habitats, increases wildfire frequency, adds to land management costs. However, identifying individual species EAG abundance from remote sensing, particularly at early stages or growth, can be problematic because overlapping controls similar phenological characteristics...
Machine‐learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method extrapolation (r = 0.86) subsurface resistivity, Landsat Thematic Mapper (TM) at‐sensor reflectance, thermal, TM‐derived spectral indices, digital elevation and other relevant spatial estimate near‐surface (0–2.6‐m depth) at 30‐m resolution. A piecewise model 0.82)...
Abstract The distribution of permafrost is important to understand because permafrost's influence on high‐latitude ecosystem structure and functions. Moreover, near‐surface (defined here as within 1 m the Earth's surface) particularly susceptible a warming climate generally poorly mapped at regional scales. Subsequently, our objectives were (1) develop first‐known binary probabilistic maps distributions 30 resolution in Alaskan Yukon River Basin by employing decision tree models, field...
Understanding the key mechanisms that control northern treelines is important to accurately predict biome shifts and terrestrial feedbacks climate. At a global scale, it has long been observed elevational latitudinal occur at similar mean growing season air temperature (GSAT) isotherms, inspiring growth limitation hypothesis (GLH) cold GSAT limits aboveground of treeline trees, with ~6–7°C. Treelines warmer than 6–7°C may indicate other limiting factors. Many globally are not advancing...
It is important to understand how upland ecosystems of Alaska, which are estimated occupy 84% the state (i.e., 1,237,774 km2 ), influencing and will influence state-wide carbon (C) dynamics in face ongoing climate change. We coupled fire disturbance biogeochemical models assess relative effects changing atmospheric dioxide (CO2 climate, logging regimes on historical future C balance for four main Landscape Conservation Cooperatives (LCCs) Alaska. At end period (1950-2009) our analysis, we...
Abstract We summarize the results of a recent interagency assessment land carbon dynamics in Alaska, which were estimated for all major terrestrial and aquatic ecosystems historical period (1950–2009) projection (2010–2099). Between 1950 2009, upland wetland (i.e., terrestrial) state gained 0.4 Tg C/yr (0.1% net primary production, NPP ), resulting cumulative greenhouse gas radiative forcing 1.68 × 10 −3 W/m 2 . The change storage is spatially variable with region Northwest Boreal Landscape...
Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, disturbances such as wildfires. Understanding the vulnerability resilience requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, more. As part a multiyear investigation...
Abstract Warming temperatures and increasing disturbance by wildfire extreme weather events is driving permafrost change across northern latitudes. The state of varies widely in space time, depending on landscape, climate, hydrologic, ecological factors. Despite its importance, few approaches commonly measure monitor the changes deep (>1 m) conditions with high spatial resolution. Here, we use electrical resistivity tomography surveys along two transects interior Alaska previously...
Wetlands are critical terrestrial ecosystems in Alaska, covering ~177,000 km2 , an area greater than all the wetlands remainder of United States. To assess relative influence changing climate, atmospheric carbon dioxide (CO2 ) concentration, and fire regime on balance wetland a modeling framework that incorporates disturbance model two biogeochemical models was used. Spatially explicit simulations were conducted at 1-km resolution for historical period (1950-2009) future projection...
Abstract Positive feedbacks between permafrost degradation and the release of soil carbon into atmosphere impact land–atmosphere interactions, disrupt global cycle, accelerate climate change. The widespread distribution thawing is causing a cascade geophysical biochemical disturbances with impacts. Currently, few earth system models account for feedback (PCF) mechanisms. This research study integrates artificial intelligence (AI) tools information derived from field-scale surveys across...
Abstract Landscape drying associated with permafrost thaw is expected to enhance microbial methane oxidation in arctic soils. Here we show that ice-rich, Yedoma deposits, comprising a disproportionately large fraction of pan-arctic soil carbon, present an alternate trajectory. Field and laboratory observations indicate talik (perennially thawed soils permafrost) development unsaturated uplands leads unexpectedly emissions (35–78 mg m −2 d −1 summer, 150–180 winter). Upland were nearly three...
Quantification of aboveground biomass (AGB) in Alaska's boreal forest is essential to the accurate evaluation terrestrial carbon stocks and dynamics northern high-latitude ecosystems. Our goal was map AGB at 30 m resolution for Yukon River Basin Alaska using Landsat data ground measurements. We acquired images generate a 3-year (2008–2010) composite top-of-atmosphere reflectance six bands as well brightness temperature (BT). constructed multiple regression model field-observed...
Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, disturbances such as wildfires. Understanding the vulnerability resilience requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, more. As part a multi-year investigation...