A5024696871- Cryospheric studies and observations
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Winter Sports Injuries and Performance
- Landslides and related hazards
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Geophysics and Gravity Measurements
- Polar Research and Ecology
- Atmospheric and Environmental Gas Dynamics
- Geological Studies and Exploration
- Climate variability and models
- Marine animal studies overview
- Coastal and Marine Management
- Ionosphere and magnetosphere dynamics
- Hydrocarbon exploration and reservoir analysis
- Icing and De-icing Technologies
- Clinical Nutrition and Gastroenterology
- Environmental Education and Sustainability
- Environmental Monitoring and Data Management
- Bat Biology and Ecology Studies
- Interdisciplinary Research and Collaboration
- Signaling Pathways in Disease
- Outdoor and Experiential Education
- Healthcare Systems and Challenges
Cooperative Institute for Research in Environmental Sciences
2014-2024
University of Colorado Boulder
2014-2024
University of Colorado System
2014-2021
National Snow and Ice Data Center
2015-2020
NOAA National Ice Center
2020
University of Washington
2008-2019
University of Bristol
2016-2019
NSF National Center for Atmospheric Research
2019
University of Oregon
2015-2016
Johns Hopkins University Applied Physics Laboratory
2008-2014
Abstract Using RADARSAT synthetic aperture radar data, we have mapped the flow velocity over much of Greenland ice sheet for winters 2000/01 and 2005/06. These maps provide a detailed view ice-sheet flow, including that hundreds glaciers draining interior. The focused patterns at coast suggest strong influence bedrock topography. Differences between our two confirm numerous early observations accelerated outlet glacier as well revealing previously unrecognized changes. overall pattern is one...
It has been widely hypothesized that a warmer climate in Greenland would increase the volume of lubricating surface meltwater reaching ice-bedrock interface, accelerating ice flow and increasing mass loss. We have assembled data set provides synoptic-scale view, spanning ice-sheet to outlet-glacier flow, with which evaluate this hypothesis. On sheet, these reveal summer speedups (50 100%) consistent with, but somewhat larger than, earlier observations. The relative speedup outlet glaciers,...
Previous studies in Greenland show that retreat of tidewater glaciers may be linked to recent increases ice loss, raising Greenland's contribution sea level rise. We examined front changes 203 glaciers, land‐terminating and terminating with shelves understand glacier behavior over three periods: 1992–2000, 2000–2006, 2006–2007. observed synchronous, sheet–wide during 2000–2006 relative coinciding a 1.1°C increase mean summer temperature at coastal weather stations. Rates for the southeast...
We report on the maturation of optical satellite-image-based ice velocity mapping over sheets and large glacierized areas, enabled by high radiometric resolution internal geometric accuracy Landsat 8's Operational Land Imager (OLI). Detailed large-area single-season mosaics time-series maps flow were created using data spanning June 2013 to 2015. The 12-bit quantization 15-m pixel scale OLI band 8 enable displacement tracking subtle snow-drift patterns sheet surfaces at ~ 1 m precision. Ice...
Earlier observations on several of Greenland's outlet glaciers, starting near the turn 21st century, indicated rapid (annual-scale) and large (>100%) increases in glacier velocity. Combining data from satellites, we produce a decade-long (2000 to 2010) record documenting ongoing velocity evolution nearly all (200+) major revealing complex spatial temporal patterns. Changes fast-flow marine-terminating glaciers contrast with steady velocities ice-shelf-terminating slow speeds land-terminating...
Predicting Greenland Ice Sheet mass loss due to ice dynamics requires a complete understanding of spatiotemporal velocity fluctuations and related control mechanisms. We present 5 year record seasonal measurements for 55 marine-terminating glaciers distributed around the sheet margin, along with ice-front position runoff data sets each glacier. Among substantial speed variations, we find three distinct patterns. One pattern indicates relatively high glacier sensitivity position. The other...
We used satellite images to examine the calving behavior of Helheim and Kangerdlugssuaq Glaciers, Greenland, from 2001 2006, a period in which they retreated sped up. These data show that many large iceberg‐calving episodes coincided with teleseismically detected glacial earthquakes, suggesting calving‐related processes are source seismicity. For each several events for we have observations, ice front calved back large, pre‐existing rift. rifts form where has thinned near flotation as...
Abstract Glacier ice discharge, which depends on velocity and terminus fluctuations, is a primary component of Greenland Ice Sheet mass loss. Some research suggests that mélange influences calving, in turn affecting glacier velocity. The details broad spatiotemporal consistency these relationships, however, undetermined. Focusing 16 northwestern glaciers during 2009 through summer 2014, we examined seasonal surface changes, position, sea conditions. For longer‐term analysis, also produced...
Abstract Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that enhance melt undercutting, leading to calving potential destabilization. Here we systematically evaluate how simulated plume structure during summer months depends on realistic ranges subglacial discharge, depth, ocean stratification 12 fjords. Our results show grounding line depth is a strong...
Abstract Mass loss from the Greenland ice sheet (GrIS) has increased over last two decades in response to changes global climate, motivating scientific community question how GrIS will contribute sea‐level rise on timescales that are relevant coastal communities. Observations also indicate impact of a melting extends beyond rise, including ocean properties and circulation, nutrient sediment cycling, ecosystem function. Unfortunately, despite rapid growth interest mass its impacts, we still...
Abstract Seasonal glacier ice velocities are important for understanding controlling mechanisms of flow. For many Greenlandic glaciers, however, these measurements limited by low temporal resolution. We present seasonal velocity changes, melt season onset and extent, front positions 45 glaciers using 2015–2017 Sentinel‐1 synthetic aperture radar data. fluctuations roughly half the appear to be primarily controlled surface melt‐induced changes in subglacial hydrology. This includes (1) that...
Abstract The mechanisms causing widespread flow acceleration of Jakobshavn Isbræ, West Greenland, remain unclear despite an abundance observations and modeling studies. Here we simulate the glacier's evolution from 1985 to 2016 using a three‐dimensional thermomechanical ice model. model captures timing 90% observed changes by forcing calving front. Basal drag in trough is low, lateral balances stream's driving stress. front position dominant control on Isbræ since viscosity shear margins...
Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group polar in Southeast Greenland. These occupy sea-ice conditions resembling those projected High Arctic late 21st century, with an annual ice-free period that >100 days longer than estimated fasting threshold species. Whereas most depend ice catch seals, Greenland have year-round hunting...
Abstract. Marine-terminating outlet glacier terminus traces, mapped from satellite and aerial imagery, have been used extensively in understanding how glaciers adjust to climate change variability over a range of timescales. Numerous studies digitized termini manually, but this process is labor intensive, no consistent approach exists. A lack coordination leads duplication efforts, particularly for Greenland, which major scientific research focus. At the same time, machine learning...
Abstract Arctic land ice is melting, sea decreasing, and permafrost thawing. Changes in these elements are interconnected, most interactions accelerate the rate of change. The changes affect infrastructure, economics, cultures people inside outside Arctic, including temperate tropical regions, through level rise, worsening storm hurricane impacts, enhanced warming. Coastal communities worldwide already experiencing more regular flooding, drinking water contamination, coastal erosion. We...
Abstract The Greenland Ice Sheet has lost mass at an accelerating rate over the last two decades, but limits of early remote sensing restricted examination localized change ice‐sheet‐wide scale. We use satellite‐derived ice sheet surface velocities, glacier terminus advance/retreat, and elevation data spanning ~1985–2015 to explore local characteristics what is now a rapid reconfiguration coastal margin. Widespread retreat more consistent climate response indicator than though velocity...
Rapid mass loss from the Greenland Ice Sheet is affecting sea level and, through increased freshwater discharge, ocean circulation, sea-ice, biogeochemistry, and marine ecosystems around Greenland. Key to interpreting ongoing projecting future ice loss, its impact on ocean, understanding exchanges of heat, freshwater, nutrients that occur at Greenland's margins. Processes governing these are poorly understood because limited observations regions where glaciers terminate into challenge model...
The Greenland Ice Sheet Ocean Science Network (GRISO) project, funded by the U.S. National Foundation (NSF), facilitates innovative approaches to geosciences education through its annual two-week summer school in Greenland. Since inception 2022, this program has become a hallmark of GRISO’s efforts cultivate interdisciplinary collaboration and foster equitable research around brings together early-career researchers from diverse disciplines nations engage with Greenland-focused...