A5068487780- Cryospheric studies and observations
- Arctic and Antarctic ice dynamics
- Winter Sports Injuries and Performance
- Geology and Paleoclimatology Research
- Climate variability and models
- Polar Research and Ecology
- Oceanographic and Atmospheric Processes
- Landslides and related hazards
- Climate change and permafrost
- Marine and coastal ecosystems
- Ocean Acidification Effects and Responses
- Adventure Sports and Sensation Seeking
- Ionosphere and magnetosphere dynamics
- Geological and Geophysical Studies
- Aerospace Engineering and Energy Systems
- Underwater Vehicles and Communication Systems
- Methane Hydrates and Related Phenomena
- Marine Biology and Ecology Research
- Ocean Waves and Remote Sensing
- Geophysics and Gravity Measurements
- Meteorological Phenomena and Simulations
- Marine and fisheries research
- Tropical and Extratropical Cyclones Research
- Marine animal studies overview
- Atmospheric and Environmental Gas Dynamics
British Antarctic Survey
2013-2025
Lamont-Doherty Earth Observatory
2016-2023
Natural Environment Research Council
2010-2022
Columbia University
2016-2022
ORCID
2021
Johns Hopkins University Applied Physics Laboratory
2016
University of Washington
2016
Earth and Space Research
2016
University of East Anglia
2016
Oceanography Society
2016
Pine Island Glacier has thinned and accelerated over recent decades, significantly contributing to global sea-level rise. Increased oceanic melting of its ice shelf is thought have triggered those changes. Observations numerical modeling reveal large fluctuations in the ocean heat available adjacent bay enhanced sensitivity ice-shelf water temperatures at intermediate depth, as a seabed ridge blocks deepest warmest waters from reaching thickest ice. Oceanic decreased by 50% between January...
Mass loss from the Antarctic Ice Sheet is driven by changes at marine margins. In Amundsen Sea, thinning of ice shelves has allowed outlet glaciers to accelerate and thin, resulting in inland migration their grounding lines. The ultimate driver often assumed be ocean warming, but recent record temperature dominated decadal variability rather than a trend. distribution water masses on Sea continental shelf particularly sensitive atmospheric forcing, while regional circulation highly variable,...
Despite rapidly growing interest in deep-sea mineral exploitation, environmental research and management have focused on impacts to seafloor environments, paying little attention pelagic ecosystems. Nonetheless, indicates that mining will generate sediment plumes noise at the seabed water column may extensive ecological effects deep midwaters (1), which can extend from an approximate depth of 200 meters 5 kilometers. Deep midwater ecosystems represent more than 90% biosphere (2), contain...
Speedup of Pine Island Glacier over the past several decades has made it Antarctica's largest contributor to sea-level rise. The speedup is largely due grounding-line retreat in response ocean-induced thinning that reduced ice-shelf buttressing. While speeds remained fairly steady from 2009 late 2017, our Copernicus Sentinel 1A/B-derived velocity data show a >12% 3 years, coincident with 19-km ice shelf. We use an ice-flow model simulate this loss, finding accelerated calving can explain...
Abstract Rapid ice loss is occurring in the Amundsen Sea sector of West Antarctic Ice Sheet. This assumed to be a long‐term response oceanographic forcing, but ocean conditions are unknown prior 1994. Here we present modeling study from 1920 2013, using an ensemble ice‐ocean simulations forced by climate model experiments. We find that during early twentieth century, likely experienced more sustained cool periods than at present. Warm become dominant over (mean trend 0.33°C/century) causing...
A combination of 15 N 2 labeling, Tyramide Signal Amplification–Fluorescent in Situ Hybridization (TSA‐FISH) assay, and chemical analyses were performed along a trophic gradient (8000 km) the equatorial Pacific. Nitrogen fixation rates low (0.06 ± 0.02 to 2.8 2.1 nmol L −1 d ) HNLC waters, higher warm pool (0.11 0.0 18.2 ), extremely high close Papua New Guinea (38 9 610 46 ). Rates attributed <10‐ μ m fraction accounted for 74% total activity. Both unicellular filamentous diazotrophs...
Abstract. Sub-ice shelf circulation and freezing/melting rates in ocean general models depend critically on an accurate consistent representation of cavity geometry. Existing global or pan-Antarctic topography data sets have turned out to contain various inconsistencies inaccuracies. The goal this work is compile independent regional surveys maps into a set. We use the S-2004 1-min bathymetry as backbone add improved version BEDMAP (ALBMAP bedrock topography) for area that roughly coincides...
Abstract. By thinning and accelerating, West Antarctic ice streams are contributing about 10% of the observed global sea level rise. Much this loss is from Pine Island Glacier, which has thinned since at least 1992, driven by changes in ocean heat transport beneath its shelf retreat grounding line. Details processes driving change, however, remain largely elusive, hampering our ability to predict future behaviour similar systems. Here, a Lagrangian methodology developed measure oceanic...
A dense grid of ice‐penetrating radar sections acquired over Pine Island Glacier, West Antarctica has revealed a network sinuous subglacial channels, typically 500 m to 3 km wide, and up 200 high, in the ice‐shelf base. These channels develop while ice is floating result from melting at base shelf. Above apex most shows isolated reflections within Comparison data with acoustic obtained using an autonomous submersible, confirms that these echoes arise open basal crevasses 50–100 wide aligned...
Abstract Pine Island Glacier (PIG) terminates in a rapidly melting ice shelf, and ocean circulation temperature are implicated the retreat growing contribution to sea level rise of PIG nearby glaciers. However, variability forcing has been poorly constrained due lack multi-year observations. Here we show, using unique record close Ice Shelf (PIIS), that there is considerable oceanic at seasonal interannual timescales, including pronounced cold period from October 2011 May 2013. This can be...
Abstract A 1/12° ocean model configuration of the Amundsen Sea sector is developed to better understand circulation induced by ice‐shelf melt and impacts on surrounding sea ice. Eighteen sensitivity experiments drag heat exchange coefficients at ice shelf/ocean interface are performed. The total rate simulated in each cavity function thermal Stanton number, for a given slightly higher lower values coefficient. Sub‐ice‐shelf induces thermohaline that pumps warm circumpolar deep water into...
Abstract We present subannual observations (2009–2014) of a major West Antarctic glacier (Pine Island Glacier) and the neighboring ocean. Ongoing retreat accelerated ice flow were likely triggered few decades ago by increased ocean‐induced thinning, which may have initiated marine sheet instability. Following subsequent 60% drop in ocean heat content from early 2012 to late 2013, slowed, but < 4%, with recovering as warmed prior temperatures. During this cold‐ocean period, evolving...
Abstract Ocean waters melt the margins of Antarctic and Greenland glaciers, individual glaciers' responses integrity their ice shelves are expected to depend on spatial distribution melt. The bases associated with Pine Island Glacier (West Antarctica) Petermann (Greenland) have similar geometries, including kilometer‐wide, hundreds‐of‐meter high channels oriented along across direction flow. enhanced by, constrain, oceanic New meter‐scale observations basal topography reveal peculiar...
The large and complex Getz Ice Shelf extends along nearly half of the West Antarctic coastline in Amundsen Sea is exposed to a more variable ocean environment than most other Pacific sector ice shelves. Ocean temperature, salinity, dissolved oxygen profiles acquired near its sub‐ice cavity openings are used here estimate seawater transports meltwater fractions. More complete coverage during 2000 2007 brackets variability observed from 1994 2011, yearlong records one front support use summer...
Observations beneath the floating section of Pine Island Glacier have revealed presence a subglacial ridge which rises up to 300 m above surrounding bathymetry. This topographic feature probably served as steady grounding line position until sometime before 1970s, when an ongoing phase rapid retreat was initiated. As result, large ocean cavity has formed behind ridge, strongly controlling circulation ice shelf and modulating water properties that cause melting in vicinity line. In order...
Abstract. Ocean-induced basal melting is responsible for much of the Amundsen Sea Embayment ice loss in recent decades, but total magnitude and spatiotemporal evolution this melt poorly constrained. To address problem, we generated a record high-resolution digital elevation models (DEMs) Pine Island Glacier (PIG) using commercial sub-meter satellite stereo imagery integrated additional 2002–2015 DEM altimetry data. We implemented Lagrangian change (Dh∕Dt) framework to estimate shelf rates at...
Abstract In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high melting near sheet grounding lines, accelerating flow, and controlling pace of future Antarctic contributions to global sea level. The pathways mCDW towards lines are crucial as they directly control heat reaching ice. A realistic representation circulation, however, remains challenging due sparsity in-situ observations difficulty ocean models reproduce available observations....
The Amundsen Sea is a key region of Antarctica where ocean, atmosphere, sea ice, and ice sheet interact. For much Antarctica, the relatively warm water open Southern Ocean (a few degrees above freezing) does not reach Antarctic continental shelf in large volumes under current climate conditions. However, Sea, penetrates onto provides heat that can melt underside area’s floating shelves, thinning them. Here, we discuss how ocean’s role melting has come increased scrutiny, present 2014...
Abstract A 63‐year observational record in the southwest Ross Sea shows a continuing, near‐linear salinity decrease of 0.170 and slight warming 0.013°C through 2020. That freshening exceeded any increase sea ice production brine release from stronger southerly winds, while melting freezing at Ice Shelf base contributed little to change. The parallel seawater density decline appears not have enhanced warm deep water intrusions onto continental shelf (CS). Confirming prior inferences, change...