A5020085772- Cryospheric studies and observations
- Climate change and permafrost
- Winter Sports Injuries and Performance
- Arctic and Antarctic ice dynamics
- Methane Hydrates and Related Phenomena
- Landslides and related hazards
- Atmospheric and Environmental Gas Dynamics
- Hydrology and Watershed Management Studies
- Flood Risk Assessment and Management
- Geology and Paleoclimatology Research
- Remote Sensing and LiDAR Applications
- Hydrology and Sediment Transport Processes
- Soil Moisture and Remote Sensing
- Geological Studies and Exploration
- Ocean Waves and Remote Sensing
- Hydrocarbon exploration and reservoir analysis
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Oil Spill Detection and Mitigation
- Precipitation Measurement and Analysis
- Underwater Acoustics Research
- Water Resources and Management
- Automated Road and Building Extraction
- Water resources management and optimization
- Remote Sensing and Land Use
- Peatlands and Wetlands Ecology
Cooperative Institute for Research in Environmental Sciences
2020-2023
University of Colorado Boulder
2020-2023
Oak Ridge Associated Universities
2023
Oak Ridge Institute for Science and Education
2023
University of California, Los Angeles
2014-2022
University of Colorado System
2020-2022
ORCID
2021
University of North Carolina at Chapel Hill
2021
John Wiley & Sons (United States)
2019
Significance Meltwater runoff from the Greenland ice sheet is a key contributor to global sea level rise and expected increase in future, but it has received little observational study. We used satellite situ technologies assess surface drainage conditions on southwestern ablation after an extreme 2012 melting event. conclude that efficiently drained under optimal conditions, digital elevation models alone cannot fully describe supraglacial its connection subglacial systems, predicting...
Greenland’s snowline exhibits large fluctuations and is a primary amplifier of ice sheet surface melt runoff.
Significance Meltwater runoff is an important hydrological process operating on the Greenland ice sheet surface that rarely studied directly. By combining satellite and drone remote sensing with continuous field measurements of discharge in a large supraglacial river, we obtained 72 h observations suitable for comparison climate model predictions. The quantify how large, fluvial catchment attenuates magnitude timing delivered to its terminal moulin hence bed. data are used calibrate...
Abstract Fine‐scale, subseasonal fluctuations in Arctic‐Boreal surface water reflect regional balance and modulate trace gas emissions to the atmosphere but have eluded detection using traditional satellite remote sensing. We use high‐resolution (~3–5 m), high‐frequency CubeSat sensors measure near‐daily changes lake area through an object‐based tracking method that incorporates machine learning overcome notable limitations of imagery. From ~76,000 images we obtain >2.2 million individual...
Abstract Fluctuations in water surface elevation (WSE) along rivers have important implications for resources, flood hazards, and biogeochemical cycling. However, current situ remote sensing methods exhibit key limitations characterizing spatiotemporal hydraulics of many the world's river systems. Here we analyze new measurements WSE slope from AirSWOT, an airborne analogue to Surface Water Ocean Topography (SWOT) mission aimed at addressing remotely sensed observations water. To evaluate...
Supraglacial meltwater channels that flow on the surfaces of glaciers, ice sheets, and shelves connect surface climatology with subglacial processes, dynamics, eustatic sea level changes. Their important role in transferring water heat across into is currently absent from models mass balance runoff contributions to global rise. Furthermore, relatively little known about genesis, evolution, hydrology, hydraulics, morphology supraglacial rivers, a first synthesis review published research...
Abstract. We document the density and hydrologic properties of bare, ablating ice in a mid-elevation (1215 m a.s.l.) supraglacial internally drained catchment Kangerlussuaq sector western Greenland sheet. find low-density (0.43–0.91 g cm−3, μ = 0.69 cm−3) to at least 1.1 depth below sheet surface. This near-surface, consists alternating layers water-saturated, porous clear solid lenses, overlain by thin (< 0.5 m), even lower (0.33–0.56 0.45 unsaturated weathering crust. Ice data from 10...
Shade-grown coffee (shade coffee) is an important component of the forested tropics, and essential to conservation forest-dependent biodiversity. Despite its importance, shade challenging map using remotely sensed data given spectral similarity land. This paper addresses this challenge in three districts northern Nicaragua, here leveraging cloud-based computing techniques within Google Earth Engine (GEE) integrate multi-seasonal Landsat 8 satellite imagery (30 m), physiographic variables...
Abstract Accurate, transparent knowledge of global reservoir levels is a prerequisite for effective management water resources. However, no complete database exists because gauge data are not globally available and the current generation satellite radar altimeters resolves only world's largest reservoirs. Here, we investigate level changes in reservoirs using ICESat‐2, National Aeronautics Space Administration (NASA)'s new laser altimetry mission. In just first 12 months mission, find that...
Abstract Areas of lakes that support emergent aquatic vegetation emit disproportionately more methane than open water but are under‐represented in upscaled estimates lake greenhouse gas emissions. These shallow areas typically less ∼1.5 m deep and can be detected with synthetic aperture radar (SAR). To assess the importance (LEV) zones to landscape‐scale emissions, we combine airborne SAR mapping field measurements vegetated open‐water flux. First, use Uninhabited Aerial Vehicle data from...
Measurements of albedo are a prerequisite for modelling surface melt across the Earth's cryosphere, yet available satellite products limited in spatial and/or temporal resolution. Here, we present practical methodology to obtain centimetre resolution with accuracies 5% using consumer-grade digital camera and unmanned aerial vehicle (UAV) technologies. Our method comprises workflow processing, correcting calibrating raw images white reference target, upward downward shortwave radiation...
Abstract. Concurrent ice sheet surface runoff and proglacial discharge monitoring are essential for understanding Greenland meltwater release. We use an updated, well-constrained river time series from the Watson River in southwest Greenland, with accurate, observation-based mass balance model of ∼ 12 000 km2 area feeding river. For 2006–2015 decade, we find a large range factor 3 interannual variability discharge. The amount is amplified 56 % by sheet's hypsometry, i.e., increase elevation....
Abstract Supraglacial lakes and rivers dominate the storage transport of meltwater on southwest Greenland Ice Sheet (GrIS) surface. Despite functioning as interconnected hydrologic networks, supraglacial are commonly studied independent features, resulting in an incomplete understanding their collective impact routing. We use Landsat 8 satellite imagery to assess seasonal evolution GrIS during 2015 melt season. Remotely sensed areas volumes compared with surface runoff simulations from three...
Extensive, complex supraglacial river networks form on the southwest Greenland ice sheet (GrIS) surface each melt season. These are dominant pathways for meltwater transport this part of sheet, but their fluvial morphometry has received little study. This paper utilizes high-resolution (2 m) WorldView-1/2 images, digital elevation models, and GIS tools to present a detailed morphometric characterization (river number, length, Strahler stream order, width, depth, bifurcation ratio, braiding...
Abstract Surface melting impacts ice sheet sliding by supplying water to the bed, but subglacial processes driving accelerations are complex. We examine linkages between surface runoff, transient storage, and short‐term motion from 168 consecutive hourly measurements of meltwater discharge (moulin input) GPS‐derived for Rio Behar, a ∼60 km 2 moulin‐terminating supraglacial river catchment on southwest Greenland Ice Sheet. Short‐term in speed correlate strongly with lag‐corrected measures ( r...
AirSWOT, an experimental airborne Ka-band interferometric synthetic aperture radar, was developed for hydrologic research and validation of the forthcoming Surface Water Ocean Topography (SWOT) satellite mission (to be launched in 2021). AirSWOT SWOT aim to improve understanding surface water processes by mapping elevation (WSE) slope (WSS) rivers, lakes, wetlands. However, utility these purposes remains largely unexamined. We present first investigation WSE WSS surveys over complex,...
Abstract Supraglacial rivers on the Greenland Ice Sheet (GrIS) transport large volumes of surface meltwater toward ocean, yet have received relatively little direct research. This study presents field observations channel width, depth, velocity, and water slope for nine supraglacial channels south‐western GrIS collected between July 23 August 20, 2012. Field sites are located up to 74 km inland span 494–1485 m elevation, contain measured discharges larger than any previous in situ study:...
The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July August 2017 as part the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced from high-resolution (1 m), co-registered CIR imagery using a semi-automated, object-based classification. resulting are available open-access datasets...
Abstract Meltwater runoff from the Greenland Ice Sheet (GrIS) significantly contributes to sea level rise and is dominant driver of enhanced mass loss. While most melt occurs during summer, little known about its seasonal and/or interannual retention within GrIS. Here, we document evidence winter, ~4 months after summer melt. Ground‐penetrating radar borehole surveys in proglacial Isortoq River reveal slowly flowing water beneath >0.5 m river ice. Geochemical analysis this indicates...
The Surface Water and Ocean Topography (SWOT) satellite AirSWOT airborne instrument are the first imaging radar-altimeters designed with near-nadir low incidence, 35.75 GHz Ka-band InSAR for mapping terrestrial water storage variability. Remotely sensed surface extents crucial assessing such variability, but confounded by emergent inundated vegetation along shorelines. However, because SWOT-like measurements novel, there remains some uncertainty in ability to detect certain land classes....
Abstract AirSWOT is an experimental airborne Ka-band radar interferometer developed by NASA-JPL as a validation instrument for the forthcoming NASA Surface Water and Ocean Topography (SWOT) satellite mission. In 2017, was deployed part of Arctic Boreal Vulnerability Experiment (ABoVE) to map surface water elevations across Alaska western Canada. The result most extensive known collection near-nadir interferometric synthetic aperture (InSAR) data derivative high-resolution (3.6 m pixel)...
Abstract. River systems in remote environments are often challenging to monitor and understand where traditional gauging apparatus difficult install or safety concerns prohibit field measurements. In such cases, sensing, especially terrestrial time-lapse imaging platforms, offer a means better these fluvial systems. One environment is found at the proglacial Isortoq southwestern Greenland, river with constantly shifting floodplain Arctic location that make situ measurements all but...
SUMMARY Climate and land-use changes are expected to drive high rates of environmental change biodiversity loss in Mediterranean ecosystems this century. This paper compares the relative future impacts land use climate on two vulnerable tree species native Southern California ( Juglans californica Quercus engelmannii ) using distribution models. Under Intergovernmental Panel for Change's A1B scenario, levels both projected could considerable habitat losses these already heavily-impacted...
Choice of watershed delineation technique is an important source uncertainty for cryo-hydrologic studies the Greenland Ice Sheet (GrIS), with different methods yielding watersheds a common pour point. First, this paper explores Akuliarusiarsuup Kuua River Northern Tributary, Western Greenland. Next, standardized, semi-automated modeling framework generating land-ice GrIS land-terminating ice (henceforth referred to as CryoSheds) using geographic information systems (GIS) hydrologic tools...