A5087893018- Cryospheric studies and observations
- Climate change and permafrost
- Soil Moisture and Remote Sensing
- Arctic and Antarctic ice dynamics
- Neural dynamics and brain function
- Functional Brain Connectivity Studies
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Landslides and related hazards
- Precipitation Measurement and Analysis
- Remote Sensing and LiDAR Applications
- Neural and Behavioral Psychology Studies
- EEG and Brain-Computer Interfaces
- Mental Health Research Topics
- Visual perception and processing mechanisms
- Cooperative Communication and Network Coding
- Advanced Wireless Network Optimization
- Geophysical Methods and Applications
- Millimeter-Wave Propagation and Modeling
- Indoor and Outdoor Localization Technologies
- Memory and Neural Mechanisms
- Advanced Mathematical Theories and Applications
- Aluminum Alloys Composites Properties
- thermodynamics and calorimetric analyses
- Forest ecology and management
- Forest Management and Policy
Jet Propulsion Laboratory
2018-2025
Rutgers, The State University of New Jersey
2016-2022
University of Southern California
2016-2020
Material Measurement Laboratory
2019
National Institute of Standards and Technology
2019
Johns Hopkins University
2019
University of Alabama at Birmingham
2015-2016
University of California, Irvine
2016
Utah State University
2013
Center for Information Technology
2012
Resting-state network connectivity has been associated with a variety of cognitive abilities, yet it remains unclear how these properties might contribute to the neurocognitive computations underlying abilities. We developed new approach-information transfer mapping-to test hypothesis that resting-state functional topology describes computational mappings between brain regions carry task information. Here, we report diverse, task-rule information in distributed can be predicted based on...
Abstract This study examines the impact of variation in root‐zone soil moisture (RZSM), a key component Earth's hydrologic cycle and climate system, on regional carbon fluxes across seven North American ecosystems. P‐band synthetic aperture radar‐derived RZSM estimates were incorporated into ecosystem demography (ED2) terrestrial biosphere model through model‐data blending approach. Analysis shows that qualitatively captures inter‐daily seasonal variability observed at flux tower sites ( r =...
Abstract Active layer thickness (ALT) is a critical metric for monitoring permafrost. How soil moisture influences ALT depends on two competing hypotheses: (a) increased increases the latent heat of fusion thaw, resulting in shallower active layers, and (b) thermal conductivity, deeper layers. To investigate their relative influence thaw depth, we analyzed Field Measurements Soil Moisture Layer Thickness (SMALT) Alaska Canada dataset, consisting thousands measurements depth collected at...
We all vary in our mental health, even among people not meeting diagnostic criteria for illness. Understanding this individual variability may reveal factors driving the risk illness, as well subclinical problems that still adversely affect quality of life. To better understand large-scale brain network mechanisms underlying variability, we examined relationship between health symptoms and resting-state functional connectivity patterns cognitive control systems. One such system is...
Abstract. An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which generally poorly represented by global models and can lead to uncertainties predicting regional ecosystem responses climate feedbacks. In this study, we developed a spatially integrated modeling analysis framework combining field observations, local-scale ( ∼ 50 m resolution) thickness (ALT) soil moisture maps derived from low-frequency (L + P-band) airborne radar measurements,...
We propose a method to estimate the active layer properties, including soil dielectric profiles and thickness (ALT), in permafrost regions using time-series P-band polarimetric synthetic aperture radar (SAR) observations. The underlying are modeled as three-layer structure with constants representing moisture freeze-thaw state of layer. To resolve ambiguity retrieved thicknesses, an approach finding largest possible depths (LPDs) is combined observations, where ALT assumed time-invariant...
Abstract. The contribution of cold-season soil respiration to the Arctic–boreal carbon cycle and its potential feedback global climate remain poorly quantified, partly due a poor understanding changes in thermal regime liquid water content during soil-freezing process. Here, we characterized processes controlling active-layer freezing Arctic Alaska using an integrated approach combining situ measurements, local-scale (∼50 m) longwave radar retrievals from NASA airborne P-band polarimetric...
Abstract Because of the remote nature permafrost, it is difficult to collect data over large geographic regions using ground surveys. Remote sensing enables us study permafrost at high resolution and areas. The Arctic‐Boreal Vulnerability Experiment's Permafrost Dynamics Observatory (PDO) contains about subsidence, active layer thickness (ALT), soil water content, table depth, derived from airborne radar measurements 66 image swaths in 2017. With nearly 58,000,000 pixels available for...
Laboratory selection experiments are alluring in their simplicity, power, and ability to inform us about how evolution works. A longstanding challenge facing with metazoans is that significant generational turnover takes a long time. In this work, we present data from unique system of experimentally evolved laboratory populations Drosophila melanogaster have experienced three distinct life-history regimes. The goal our study was determine quickly certain regime diverge phenotypically...
Interferometric synthetic aperture radar (InSAR) has been used to quantify a range of surface and near physical properties in permafrost landscapes. Most previous InSAR studies have utilized spaceborne platforms, but datasets over landscapes collected from airborne platforms steadily growing recent years. existing algorithms dedicated toward retrieval were originally developed for platforms. In this study, which is the first two part series, we introduce series calibration techniques apply...
Abstract Organic matter (OM) content and a shallow water table are two key variables that govern the physical properties of subsurface within active layer arctic soils underlain by permafrost, where majority biogeochemical activities take place. A detailed understanding soil moisture OM profile behavior over short vertical distances through is needed to adequately model processes. To observe characterize profiles in layer, we conducted sampling at five sites along Dalton Highway on Alaska’s...
Attention facilitates the processing of task-relevant visual information and suppresses interference from task-irrelevant information. Modulations neural activity in cortex depend on attention, likely result signals originating fronto-parietal cingulo-opercular regions cortex. Here, we tested hypothesis that attentional facilitation is accomplished part by changes how brain networks involved control interact with sectors V1 represent different retinal eccentricities. We measured strength...
The Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) P-band synthetic aperture radar (SAR) was flown more than 1200 h from August 2012 to September 2015, covering regions 2500 km <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> spread over nine major biomes in North America. flights, as a part the NASA AirMOSS Earth Venture Suborbital 1 (EVS-1) mission, collected data used map root-zone soil moisture (RZSM) at 3-arcsec...
How cognitive task behavior is generated by brain network interactions a central question in neuroscience. Answering this calls for the development of novel analysis tools that can firstly capture neural signatures information with high spatial and temporal precision (the "where when") then allow empirical testing alternative models function link to "how"). We outline modeling approach suited purpose applied noninvasive functional neuroimaging data humans. first dynamically decoded...
Abstract Seasonal subsidence induced by ground ice melt can be measured interferometric synthetic aperture radar (InSAR) techniques to infer active layer thickness (ALT) in permafrost regions. The magnitude of depends on both how deep the soil thawed and much ice/water content existed soil. To provide later, P‐band polarimetric (PolSAR) backscatter is used due its sensitivity subsurface moisture freeze/thaw conditions. In this study, which second a two‐part series Permafrost Dynamics...
Abstract. This study introduces and evaluates a comprehensive, model-generated dataset of Northern Hemisphere permafrost conditions at 81 km2 resolution. Surface meteorological forcing fields from the Modern-Era Retrospective Analysis for Research Applications 2 (MERRA-2) reanalysis were used to drive an improved version land component MERRA-2 in middle-to-high northern latitudes 1980 2017. The resulting simulated distribution across mostly captures observed extent continuous discontinuous...
Abstract. Permafrost-affected ecosystems of the Arctic–boreal zone in northwestern North America are undergoing profound transformation due to rapid climate change. NASA's Arctic Boreal Vulnerability Experiment (ABoVE) is investigating characteristics that make these vulnerable or resilient this ABoVE employs airborne synthetic aperture radar (SAR) as a powerful tool characterize tundra, taiga, peatlands, and fens. Here, we present an annotated guide L-band P-band SAR data acquired during...
Much of our lives are spent in unconstrained rest states, yet cognitive brain processes primarily investigated using task-constrained states. It may be possible to utilize the insights gained from experimental control task as reference points for investigating rest. To facilitate comparison and functional magnetic resonance imaging data, we focused on activation amplitude patterns, commonly used but not analyses. During rest, identified spontaneous changes temporally extended whole-brain...
Abstract Surface organic carbon content and soil moisture (SM) represent first‐order controls on permafrost thaw vulnerability, yet remain challenging to map accurately. Here we explored the links between surface properties SM dynamics in Alaska North Slope through data analysis process‐based modeling. Our analysis, based situ brightness temperature from Soil Moisture Active Passive (SMAP) mission, indicated that drydown process Arctic tundra is closely related (SOC) properties. More rapid...
A novel miniaturized design of a microstrip-fed slot antenna is presented. By properly loading pair C-shaped rings inside half-wavelength slot, the fundamental resonant frequency can be significantly decreased. This letter illustrates mechanism miniaturization and key dimension parameter analysis. An optimized with 50% size reduction was fabricated measured, where very good agreement between simulation measurement obtained. The results show that presented miniature maintains nominal...
In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have emerged as a method for observing seasonal thaw subsidence, soil moisture, in regions. This study validates SAR-derived estimates three regions Alaska, USA using calibrated ground penetrating (GPR)...
In this paper, a harmonized soil parametrization that accounts for both organic matter (SOM) content and degree of decomposition are used to parametrize the hydraulic properties permafrost soils. Using wilting point calculated from soil-water retention curve inform amount bound water in medium, we construct dielectric mixing model effective across full range SOM levels. The active layer soils parametrized as profile functions moisture radar retrievals. NASA P-band Airborne Microwave...
In this paper, a dual-frequency permafrost active layer thickness (ALT) retrieval algorithm is presented wherein P-band AirMOSS and L-band UAVSAR data are used to retrieve the layered soil dielectric constants thicknesses. Using known radar calibration accuracy, sensing depth defined help understand limit of backscatter sensitivity subsurface conditions as consistency check when determining ALT. Retrieved maps thicknesses show high spatial correlation with vegetation type organic thickness....
In this paper, an active layer thickness (ALT) retrieval algorithm is presented wherein time-series of P- and L-band radar observations are used simultaneously to retrieve the depth from ground surface permafrost table. Several model assumptions for two soil conditions (maximum thaw partially frozen) made based on in situ temperature moisture data. It expected that measurements can provide different aspects structure retrieving accurate ALT. Monte Carlo numerical simulations performed show...