A5012788619- Climate change and permafrost
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Forest ecology and management
- Remote Sensing and LiDAR Applications
- Land Use and Ecosystem Services
- Atmospheric and Environmental Gas Dynamics
- Fire effects on ecosystems
- Remote Sensing in Agriculture
- Geological Studies and Exploration
- Ecology and Vegetation Dynamics Studies
- Tree-ring climate responses
- Methane Hydrates and Related Phenomena
- Peatlands and Wetlands Ecology
- Indigenous Studies and Ecology
- Conservation, Biodiversity, and Resource Management
- Forest Management and Policy
- Plant Water Relations and Carbon Dynamics
- Forest Biomass Utilization and Management
- Arctic and Antarctic ice dynamics
- Hydrocarbon exploration and reservoir analysis
- Species Distribution and Climate Change
- Radiomics and Machine Learning in Medical Imaging
- Agriculture and Rural Development Research
- Science and Climate Studies
Goddard Space Flight Center
2017-2025
Earth System Science Interdisciplinary Center
2023-2025
University of Maryland, College Park
2011-2025
Mental Illness Research, Education and Clinical Centers
2025
Universities Space Research Association
2017-2024
University of Maryland, Baltimore County
2022-2024
University of Virginia
2013-2024
McCormick (United States)
2013-2024
Abstract Significant progress in permafrost carbon science made over the past decades include identification of vast stocks, development new pan‐Arctic maps, an increase terrestrial measurement sites for CO 2 and methane fluxes, important factors affecting cycling, including vegetation changes, periods soil freezing thawing, wildfire, other disturbance events. Process‐based modeling studies now key elements cycling advances statistical inverse enhance understanding region C budgets. By...
Individual-based models (IBMs) of complex systems emerged in the 1960s and early 1970s, across diverse disciplines from astronomy to zoology. Ecological IBMs arose with seemingly independent origins out tradition understanding ecosystems dynamics a 'bottom-up' accounting interactions parts. Individual trees are principal among parts forests. Because these computationally demanding, they have prospered as power digital computers has increased exponentially over decades following 1970s.
Abstract Ecosystems in the North American Arctic-Boreal Zone (ABZ) experience a diverse set of disturbances associated with wildfire, permafrost dynamics, geomorphic processes, insect outbreaks and pathogens, extreme weather events, human activity. Climate warming ABZ is occurring at over twice rate global average, as result extent, frequency, severity these are increasing rapidly. Disturbances span wide gradient spatiotemporal scales have varying impacts on ecosystem properties function....
The boreal zone of Alaska is dominated by interactions between disturbances, vegetation, and soils. These are likely to change in the future through increasing permafrost thaw, more frequent intense wildfires, vegetation from drought competition. We utilize an individual tree-based model, University Virginia Forest Model Enhanced (UVAFME), estimate current forest conditions across sites within interior Alaska. updated UVAFME for application Alaska, including improved simulation dynamics,...
Forests are important ecosystems that under increasing pressure from human use and environmental change, have a significant ability to remove carbon dioxide the atmosphere, therefore focus of policy efforts aimed at reducing deforestation degradation as well afforestation reforestation for climate mitigation. Critical these is accurate monitoring, reporting verification current forest cover stocks. For planning, additional step modeling required quantitatively estimate sequestration...
Africa is entering a new fire paradigm, with climate change and increasing anthropogenic pressure shifting the patterns of frequency severity. Thus, it crucial to use available information technologies understand vegetation dynamics during post-fire recovery processes. The main objective this study was evaluate seasonal spatio-temporal trends in response fires across Africa, from 2001 2020. Non-parametric tests were used analyze MODIS Normalized Difference Vegetation Index (NDVI) products...
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...
Abstract Introduction Veterans with a history of traumatic brain injury (TBI) are significantly more likely to develop insomnia than their non-injured peers, which contributes functional impairment and diminished quality life. Emerging evidence suggests that circadian abnormalities may underlie sizeable subset sleep disturbances following TBI, yet such remain under-detected in this patient population. Pragmatic methods estimate timing (e.g., dim light melatonin onset [DLMO]) the homes...
Abstract Accurate accounting of aboveground biomass density (AGBD) is crucial for carbon cycle, biodiversity, and climate change science. The Global Ecosystem Dynamics Investigation (GEDI), which maps global AGBD from waveform lidar, the first a new generation Earth observation missions designed to improve accounting. This paper explores possibility that lidar waveforms may not be unique AGBD—that forest stands with different produce highly similar waveforms—and we hypothesize non-uniqueness...
Abstract The direction and magnitude of tundra vegetation productivity trends inferred from the normalized difference index (NDVI) have exhibited spatiotemporal heterogeneity over recent decades. This study examined spatial temporal drivers Moderate Resolution Imaging Spectroradiometer Max NDVI (a proxy for peak growing season aboveground biomass) time-integrated (TI)-NDVI total productivity) on Yamal Peninsula, Siberia, Russia between 2001 2018. A suite remotely-sensed environmental machine...
Abstract. Wetlands are the largest natural source of methane (CH4) emissions globally. Northern wetlands (>45° N), accounting for 42 % global wetland area, increasingly vulnerable to carbon loss, especially as CH4 may accelerate under intensified high-latitude warming. However, magnitude and spatial patterns remain relatively uncertain. Here we present estimates daily fluxes obtained using a new machine learning-based upscaling framework (WetCH4) that applies most complete database eddy...
This study documents the community composition and forest structure of lowland rainforest in eastern Madagascar, with a first quantitative description primary Reserve Naturelle Intégrale de (RNI) Betampona. An intensive field survey vegetation environmental factors was conducted over two consecutive campaigns RNI Betampona, an isolated reserve located ca. 40 km northwest city Toamasina. One hundred 10 m-diameter plots were inventoried re-measured 2004 2005. Two forty-four tree species...
Abstract Forest structure—the height, cover, vertical complexity, and spatial patterns of trees—is a key indicator productivity variation across forested extents. During the 2017 2019 growing seasons, NASA’s Arctic-Boreal Vulnerability Experiment collected full-waveform airborne LiDAR using land, vegetation imaging sensor, sampling boreal tundra landscapes variety ecological regions from central Canada westward through Alaska. Here, we compile archive geo-referenced gridded suite these data...
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...
GIEMS2 represents the minimum extents of northern wetlands.**GLWD provides a representation maximum extent wetlands.***These numbers are derived from CT natural microbial emissions, which include emissions wetlands, river/lake/pond systems, and possibly wild animals (despite small amount).
Abstract Biodiversity, when viewed through the combined lenses of compositional, structural, and functional attributes, provides for a holistic understanding complexities found within community assemblages ecosystems. However, advancement in our how ecosystem diversity interacts with structural compositional metrics is lacking, part because universally applied methodologies to derive classifications are still under development vary widely across scales, extents biomes. This study presents...
Ecological modeling and forecasting are essential tools for the understanding of complex vegetation dynamics. The parametric demands some these models often lacking or scant threatened ecosystems, particularly in diverse tropical ecosystems. One such ecosystem also one world’s biodiversity hotspots, Madagascar’s lowland rainforests, have disappeared at an alarming rate. processes that drive tree species growth distribution remain as poorly understood themselves. We investigated application...
Consideration of scale is essential when examining structural relationships in forests. In this study, we present a parameterization the FORMIND individual-based forest model for old growth Atlantic lowland rainforest La Selva, Costa Rica. Results show that simulated reproduces complexity Rican within 2.3% aboveground biomass values, based on comparisons with CARBONO inventory plot data. The Rica simulation was then used to investigate relationship between canopy height and (AGB), leaf area...