A5064637919- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Climate variability and models
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Isotope Analysis in Ecology
- Polar Research and Ecology
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Groundwater and Isotope Geochemistry
- Landslides and related hazards
- Winter Sports Injuries and Performance
- Pleistocene-Era Hominins and Archaeology
- Tree-ring climate responses
- Geological Studies and Exploration
- Marine and coastal ecosystems
- Aeolian processes and effects
- Atmospheric chemistry and aerosols
- Water Quality and Resources Studies
- Interdisciplinary Research and Collaboration
- Geophysics and Gravity Measurements
- Urban Heat Island Mitigation
- Geological and Tectonic Studies in Latin America
- Per- and polyfluoroalkyl substances research
- Ocean Acidification Effects and Responses
University of Colorado Boulder
2020-2025
Institute of Arctic and Alpine Research
2020-2025
University of Colorado System
2021-2024
University of Washington
2013-2023
Earth and Space Research
2013-2022
California Institute of Technology
2019-2021
University of California, Santa Barbara
2018-2021
Seattle University
2015
GNS Science
2011
Victoria University of Wellington
2011
Abstract. The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep that provides climate records of the past ∼68 ka at unprecedented temporal resolution. upper 2850 m (back to 31.2 BP) have been dated using annual-layer counting. Here we present chronology for part (67.8–31.2 BP), which based on stratigraphic matching annual-layer-counted Greenland cores globally well-mixed atmospheric methane. We calculate WD gas age–ice age difference (Δage)...
Abstract The Antarctic contribution to sea level is a balance between ice loss along the margin and accumulation in interior. Accumulation records for past few decades are noisy show inconsistent relationships with temperature. We investigate relationship temperature 31 ka using high‐resolution from West Ice Sheet (WAIS) Divide core Antarctica. Although glacial‐interglacial increases result high correlation moderate sensitivity full record, shows considerable variability through time 0–8...
Abstract We use a high‐resolution water isotope record from the West Antarctic Ice Sheet Divide ice core (WDC) to evaluate effects of diffusion for last 29 ka B.P. Using spectral analysis data, we determine lengths in depth and time domains. The length quantifies mean cumulative diffusive displacement molecules relative their original location at deposition. simulate observed signal with models find that our understanding processes conditions sheet is incomplete. With ice‐deformational...
Abstract. Oxygen and hydrogen isotope ratios in polar precipitation are widely used as proxies for local temperature. In combination, oxygen also provide information on sea surface temperature at the oceanic moisture source locations where originates. Temperature reconstructions obtained from ice-core records generally rely linear approximations of relationships among temperature, water-isotope values. However, there important nonlinearities that significantly affect such reconstructions,...
Abstract The recovery of long-term climate proxy records with seasonal resolution is rare because natural smoothing processes, discontinuities and limitations in measurement resolution. Yet insolation forcing, a primary driver multimillennial-scale change, acts through variations direct impacts on 1 . Whether the sensitivity to matches theoretical predictions has not been assessed over long timescales. Here, we analyse continuous record water-isotope ratios from West Antarctic Ice Sheet...
Abstract Globally, glaciers and icefields contribute significantly to sea level rise. Here we show that ice loss from Juneau Icefield, a plateau icefield in Alaska, accelerated after 2005 AD. Rates of area shrinkage were 5 times faster 2015–2019 than 1979–1990. Glacier volume remained fairly consistent (0.65–1.01 km 3 −1 ) 1770–1979 AD, rising 3.08–3.72 1979–2010, then doubling 2010 reaching 5.91 ± 0.80 (2010–2020). Thinning has become pervasive across the since 2005, accompanied by glacier...
Abstract. Water isotopes in ice cores are used as a climate proxy for local temperature and regional atmospheric circulation well evaporative conditions moisture source regions. Traditional measurements of water have been achieved using magnetic sector isotope ratio mass spectrometry (IRMS). However, number recent studies shown that laser absorption (LAS) performs or better than IRMS. The new LAS technology has combined with continuous-flow analysis (CFA) to improve data density sample...
Abstract Measurements of the 17 O excess H 2 were obtained from ice cores in West and East Antarctica. Combined with previously published results Antarctica, new data provide most complete spatial temporal view Antarctic to date. There is a steep gradient present‐day precipitation across higher values marine‐influenced regions lower interior. also pattern change between Last Glacial Maximum (LGM) Holocene periods. At coastal locations, there no significant . both Ice Sheet Divide site at...
Abstract Over the past 40 years, Arctic sea ice minimum in September has declined. The period between 2007 and 2012 showed accelerated melt contributed to record minima of 2012. Here, observational model evidence shows that changes summer since 2000s reflect a continuous anthropogenically forced melting masked by interdecadal variability atmospheric circulation. This variation is partially driven teleconnections originating from surface temperature (SST) east-central tropical Pacific via...
Synoptic variability in the Ross Sea region, Antarctica over last thirty years is investigated using back‐trajectory modeling and cluster analysis. We identify two dominant air‐mass trajectory clusters: oceanic/West Antarctic continental/East Antarctic. Our analysis shows that trajectories have an annual cycle similar to Semiannual Oscillation on average peak frequency during April, while reach their maximum December. demonstrate a causal association between El Niño Southern (ENSO) of...
Abstract. The sub-Antarctic is one of the most data-sparse regions on earth. A number glaciated Antarctic and islands have potential to provide unique ice core records past climate, atmospheric circulation, sea ice. However, very little known about glaciology these remote or their vulnerability warming temperature. Here we present melt histories density profiles from shallow (firn) cores (14 24 m) drilled three two coastal domes. Additionally, complementary ground-penetrating radar (GPR)...
Abstract Increased rain over the Greenland Ice Sheet can accelerate ice sheet mass loss and sea level rise. Here, 14 years of unique spaceborne‐radar observations provide an observational constraint on increased occurrence in a warming climate. Combining these satellite‐based precipitation with near‐surface temperature reveals spatial temporal distribution modern (2006–2020) snow rain. This serves as foundation for determining increase due to atmospheric alone. Rain doubles under 2.3°C local...
The Juneau Icefield, Alaska, lost ice at an accelerated rate after 2005, relative to the past 250 years. Rates of area shrinkage were found be 5 times faster from 2015–2019 than 1979–1990. continuation this trend could push glacial retreat beyond point possible recovery.Climate-driven loss glaciers and icefields has been shown contribute rising sea-levels, with Alaska expected remain largest regional contributor effect up year 2100. Alaskan are particularly vulnerable...
Anthropogenic nitrogen oxide (NOx = NO + NO2) emissions have increased since the Industrial Revolution as a result of fossil fuel burning, contributing to increasing atmospheric acidity and changes oxidative capacity atmosphere. Oxidation NOx leads formation nitrate both in gas phase (HNO3(g)) aerosol (p-NO3–), which may then be removed from atmosphere via wet dry deposition. Ice core records thus used infer past concentrations given high enough accumulation rates prevent...
Prior results from EGRIP (East Greenland Icesheet Project ice core) indicate that interannual-to-decadal variability in water isotopes lead abrupt Dansgaard-Oeschger event (D-O Events) warming by hundreds of years. As part the U.S. National Science Foundation funded “Beyond Mean Climate” project, GISP2 (Greenland Ice Sheet 2 is being resampled at NSF-Ice Core Facility and reanalyzed for high resolution isotope measurements INSTAAR, University Colorado. gives us chance to...