ORCID Profile
0000-0002-9183-0178
Current Organisations
Earth and Space Research
,
Rutgers University New Brunswick
,
Oregon State University
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Publisher: Wiley
Date: 19-03-2020
Publisher: Wiley
Date: 19-03-2020
Publisher: Springer Science and Business Media LLC
Date: 27-05-2019
Publisher: Springer Science and Business Media LLC
Date: 03-07-2018
Publisher: Elsevier BV
Date: 2002
Publisher: Research Square Platform LLC
Date: 22-08-2023
DOI: 10.21203/RS.3.RS-3277941/V1
Abstract: Tides in the Arctic Ocean affect ocean circulation and mixing, and sea ice dynamics and thermodynamics. However, there is a limited network of available in situ tidal coefficient data for understanding tidal variability in the Arctic Ocean e.g., the global TICON-3 database contains only 111 sites above 60ºN and 21 above 70ºN. At the same time, the presence of sea ice and latitude limits of satellite altimetry complicates altimetry-based retrievals of Arctic tidal coefficients. This leads to a reliance on ocean tide models that require validation and reliable data for assimilation into inverse solutions. Here, we present a comprehensive new dataset of tidal constituents in the Arctic region, combining analyses of in situ measurements from tide gauges, ocean bottom pressure sensors and GNSS interferometric reflectometry. The new dataset contains 914 measurement sites above 60ºN and 399 above 70ºN, with each site being quality-assessed and expert guidance provided to help maximise the usage of the dataset. We also compare the dataset to recent tide models.
Publisher: American Geophysical Union (AGU)
Date: 06-2003
DOI: 10.1029/2001JC001169
Publisher: Copernicus GmbH
Date: 06-02-2018
Abstract: Abstract. Recent modeling studies of ocean circulation in the southern Weddell Sea, Antarctica, project an increase over this century of ocean heat into the cavity beneath Filchner–Ronne Ice Shelf (FRIS). This increase in ocean heat would lead to more basal melting and a modification of the FRIS ice draft. The corresponding change in cavity shape will affect advective pathways and the spatial distribution of tidal currents, which play important roles in basal melting under FRIS. These feedbacks between heat flux, basal melting, and tides will affect the evolution of FRIS under the influence of a changing climate. We explore these feedbacks with a three-dimensional ocean model of the southern Weddell Sea that is forced by thermodynamic exchange beneath the ice shelf and tides along the open boundaries. Our results show regionally dependent feedbacks that, in some areas, substantially modify the melt rates near the grounding lines of buttressed ice streams that flow into FRIS. These feedbacks are introduced by variations in meltwater production as well as the circulation of this meltwater within the FRIS cavity they are influenced locally by sensitivity of tidal currents to water column thickness (wct) and non-locally by changes in circulation pathways that transport an integrated history of mixing and meltwater entrainment along flow paths. Our results highlight the importance of including explicit tidal forcing in models of future mass loss from FRIS and from the adjacent grounded ice sheet as in idual ice-stream grounding zones experience different responses to warming of the ocean inflow.
Publisher: Elsevier BV
Date: 2006
Publisher: American Geophysical Union (AGU)
Date: 14-06-2021
DOI: 10.1029/2020GL091207
Abstract: Mass loss from Antarctica’s three largest ice shelves is dominated by calving, primarily of large tabular icebergs every few decades. Smaller, more frequent calving events also occur, but it is more difficult to detect them and quantify their contribution to total ice‐shelf mass loss. We used surface elevation data from NASA’s ICESat‐2 laser altimeter to examine the structure of the Ross Ice Shelf front between October 2018 and July 2020. Profiles frequently show a depression a few meters deep about 200–800 m upstream of the front, with higher values on the eastern portion of the ice shelf. This structure results from bending due to buoyancy of a submerged ice bench generated by ice‐front melting near the waterline when warm water is present in summer. These bending stresses may cause small‐scale calving events whose frequency would change as summer sea ice and atmosphere–ocean heat exchanges vary over time.
Publisher: American Geophysical Union (AGU)
Date: 22-02-2014
DOI: 10.1002/2013GL059153
Publisher: Springer Science and Business Media LLC
Date: 08-01-2018
DOI: 10.1038/S41561-017-0033-0
Abstract: Satellite observations over the past two decades have revealed increasing loss of grounded ice in West Antarctica, associated with floating ice shelves that have been thinning. Thinning reduces an ice-shelf's ability to restrain grounded-ice discharge, yet our understanding of the climate processes that drive mass changes is limited. Here, we use ice-shelf height data from four satellite altimeter missions (1994-2017) to show a direct link between ice-shelf-height variability in the Antarctic Pacific sector and changes in regional atmospheric circulation driven by the El Niño-Southern Oscillation. This link is strongest from Dotson to Ross ice shelves and weaker elsewhere. During intense El Niño years, height increase by accumulation exceeds the height decrease by basal melting, but net ice-shelf mass declines as basal ice loss exceeds lower-density snow gain. Our results demonstrate a substantial response of Amundsen Sea ice shelves to global and regional climate variability, with rates of change in height and mass on interannual timescales that can be comparable to the longer-term trend, and with mass changes from surface accumulation offsetting a significant fraction of the changes in basal melting. This implies that ice-shelf height and mass variability will increase as interannual atmospheric variability increases in a warming climate.
Publisher: Elsevier BV
Date: 06-2009
No related grants have been discovered for Susan Howard.