NSFPLR-NERC: Thwaites-Amundsen Regional Survey and Network (TARSAN)
Lead Research Organisation:
University of East Anglia
Department Name: Environmental Sciences
Abstract
Thwaites and neighboring glaciers in the Amundsen Sea Embayment (ASE) are rapidly losing mass in response to recent climate warming and related changes in ocean circulation. Ice-sheet models suggest that the mass loss from the ASE will further accelerate in the near future, initiating an eventual collapse of the West Antarctic Ice Sheet (WAIS), raising the global sea level by up to 2.5 meters in as short as 500 years. Such model predictions, however, are still lacking spatially and temporally detailed understanding of the dominant processes at and near grounding zones and the atmospheric and oceanic drivers of these processes. The proposed project aims to constrain these dominant processes affecting the Thwaites and the Dotson Ice Shelves, as well as the grounded ice mass buttressed by these ice shelves. Specific objectives are: 1) to install atmosphere-ice-ocean multi-sensor remote autonomous stations (AMIGOS) on the ice shelves for two years to provide sub-daily continuous observations of concurrent oceanic, glaciologic, and atmospheric conditions; 2) measure ocean properties on the continental shelf adjacent to the ice-shelf fronts (using seal tagging, glider-based and ship-based surveys and existing moored and CTD-cast data) and into the sub-ice-shelf cavities (using Autonomous Underwater Vehicles AUVs) to detail ocean transports and heat fluxes affecting the ice-shelf base; and 3) constrain the current ice-shelf and sub-ice-shelf cavity geometry, ice flow, and firn properties for the two ice-shelf sites (using radar, active-source seismic and gravimetric methods) to better understand the impact of ocean and atmosphere on the ice-sheet change.
Planned Impact
Public Engagement and Educational Outreach: Science writer Doug Fox (inc. National Geographic, Discover, and Scientific American) will be embedded with the field team and write a series of articles highlighting the science and the societal impacts of this work. Fox's focused, in-depth coverage of the research will be coupled with a social media campaign: "Live from the Ice". This social media campaign will include a weblog and Twitter feed that tells stories and announces intriguing observations in real time based on the measurements from the Iridium-uplinked AMIGOS-III data and tagged seals. The general model will follow the highly successful NSIDC Arctic Sea Ice News and Analysis website and the NASA Curiosity "Martian Diaries" , and @MarsCuriosity Twitter feed. The website will be hosted by NSIDC and include discussion of background concepts relating ice-shelf, ocean, and atmospheric processes. Monthly entries will include blogs, video blogs, or short educational videos, depending on the content and message, geared toward middle-school level science students and the science-interested public. The blog, Twitter feed, and other social media would be told from the perspective of sensor system at the edge of the ice, a tag on a seal, or the Autosub. The topics would range from the 'personal' - such as describing a storm or a cold weather event in the context of the Antarctic climate - to the expansive, such as discussing the Antarctic ice-sheet, climate change, and ocean conditions and events. One targeted audience for the blog is middle and high school students. Members of the public will be able to "adopt" a seal, and see the location of their seal on the website in real time, with the warmest and coldest water they encountered and the depth they dived to, superimposed on a sea ice image each day. We will publicize the social media feeds through the US National Science Teachers Association and UK Teacher-Scientist Network, and provide an alternative email listserv for teachers to follow all "Live from the Ice" stories. We will engage with the public early on in the project so that they can follow the project from start to finish. For selected stories, we will provide an annotated spreadsheet file with data, calculations, and plots for teachers to integrate into their teaching activities. AMIGOS-III and seal-tagging data including movement patterns of the seals will also be presented as interactive displays for schools and public science meetings incorporating live data feeds.The collaborative team members regularly participate in K-12 outreach efforts through local school presentations and field workshops, and would continue to conduct these during the proposed work.
Organisations
People |
ORCID iD |
| Karen J. Heywood (Principal Investigator) | |
| Rob Hall (Co-Investigator) |
Publications
Alley K
(2021)
Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
in The Cryosphere
Alley K
(2024)
Evolution of sub-ice-shelf channels reveals changes in ocean-driven melt in West Antarctica
in Journal of Glaciology
Davis PED
(2023)
Suppressed basal melting in the eastern Thwaites Glacier grounding zone.
in Nature
Dotto T
(2023)
Mixing Processes in the Dotson Ice Shelf Outflow
Dotto TS
(2022)
Ocean variability beneath Thwaites Eastern Ice Shelf driven by the Pine Island Bay Gyre strength.
in Nature communications
Graham A
(2022)
Rapid retreat of Thwaites Glacier in the pre-satellite era
in Nature Geoscience
| Description | We have measured for the first time the water masses flowing under the Thwaites ice shelf. We showed the changes in ocean circulation caused by the retreat of the Pine Island Glacier. We measured the winter time meltwater using sensors on seals' heads, for the first time. |
| Exploitation Route | Ocean modellers might evaluate their models against these results. |
| Sectors | Environment |
| Description | BIOPHYSO |
| Amount | € 500,000 (EUR) |
| Organisation | Marie Sklodowska-Curie Actions |
| Sector | Charity/Non Profit |
| Country | Global |
| Start | 07/2026 |
| End | 08/2028 |
| Title | Gravity-derived bathymetry for the Thwaites, Crosson and Dotson ice shelves (2009-2019) |
| Description | This dataset is an estimate of sub ice shelf bathymetry beneath the Thwaites, Crosson and Dotson ice shelves. The output bathymetry is derived from a new compilation of gravity data collected up to the end of the 2018/19 field season. The input gravity dataset includes airborne data from Operation Ice Bridge (OIB) and the NERC/NSF International Thwaites Glacier Collaboration (ITGC), and marine gravity from the R/V Nathaniel B. Palmer cruise NBP19-02. The recovered bathymetry was constrained by swath bathymetry and onshore airborne radio-echo depth sounding data in the surrounding area. Ice shelves mask the critical link between the ocean and cryosphere systems, and hence accurate sub ice shelf bathymetry is critical for generating reliable models of future ice sheet change. Included in the data release is the input free air gravity data, constraining bathymetry/sub-ice topography, and output gravity derived bathymetry. This work was funded by the British Antarctic Survey core program (Geology and Geophysics team), in support of the joint Natural Environment Research Council (NERC)/ National Science Foundation (NSF) International Thwaites Glacier Collaboration (ITGC). Additional specific support came from NERC Grants: NE/S006664/1 and NE/S006419/1, and NSF Grants: NSF1842064, NSFPLR-NERC-1738942, NSFPLR-NERC-1738992 and NSFPLR-NERC-1739003. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01332 |
| Title | Shipborne ADCP data in the Thwaites Gyre region, 2019 |
| Description | This dataset contains the velocity profiles in the Thwaites Gyre region collected by the shipborne Acoustic Doppler Current Profiler (ADCP) onboard RV Nathaniel B Palmer in 2019 under the project Thwaites-Amundsen Regional Survey and Network Integrating Atmosphere-Ice-Ocean Processes (TARSAN). Ocean current velocities over the upper 980 m of the water column were obtained using a 75 kHz Ocean Surveyor (OS75) and a 38 kHz Ocean Surveyor (OS38) shipboard Acoustic Doppler Current Profiler (sADCP). Common Ocean Data Access System (CODAS) processing has been run to generate the NetCDF files. The authors made additional quality control including, 1. removing data with velocity values higher than 0.6 m/s and other obvious outliners, and 2. removing data below 400 m for OS75 and data below 760 m for OS38 as the last several levels in the velocity profiles are believed to be potentially affected by the water turbidity and bubbles passing below the sADCP etc. The data are stored in .txt format and .mat MATLAB format. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://zenodo.org/record/6757569 |
| Title | Shipborne ADCP data in the Thwaites Gyre region, 2019 |
| Description | This dataset contains the velocity profiles in the Thwaites Gyre region collected by the shipborne Acoustic Doppler Current Profiler (ADCP) onboard RV Nathaniel B Palmer in 2019 under the project Thwaites-Amundsen Regional Survey and Network Integrating Atmosphere-Ice-Ocean Processes (TARSAN). Ocean current velocities over the upper 980 m of the water column were obtained using a 75 kHz Ocean Surveyor (OS75) and a 38 kHz Ocean Surveyor (OS38) shipboard Acoustic Doppler Current Profiler (sADCP). Common Ocean Data Access System (CODAS) processing has been run to generate the NetCDF files. The authors made additional quality control including, 1. removing data with velocity values higher than 0.6 m/s and other obvious outliners, and 2. removing data below 400 m for OS75 and data below 760 m for OS38 as the last several levels in the velocity profiles are believed to be potentially affected by the water turbidity and bubbles passing below the sADCP etc. The data are stored in .txt format and .mat MATLAB format. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://zenodo.org/record/6757570 |
| Title | An Idealised Barotropic Ocean Gyre Model Code, Based on MITgcm |
| Description | This dataset is supplementary to The Cryosphere paper "Reversal of ocean gyres near ice shelves in the Amundsen Sea caused by the interaction of sea ice and wind". A full model description and the application can be found in the paper. Here is the modified version of the model set-up written in the paper in the chapter 3. This model is based on the MIT general circulation model (MITgcm; MITgcm's user manual 4.1; Marshall et al., 1997) with an idealised barotropic set-up. The model has an ocean domain with a size of 60 × 60 km and a horizontal grid spacing of 1 km. It has one 1-km-thick vertical layer with a free surface. All simulations are run for six model months, which allows all of them to spin up to be sufficiently close to a steady state. The spin-up time of the simulations varies from 51 days to 91 days, assessed as the time at which the daily change of the total kinetic energy of the ocean is less than 0.1% of the total kinetic energy of the ocean at the final model day of the 6 model months. The wind field is the only external forcing applied to the model ocean. We generate a simplified wind forcing field based on the key features of the climatological wind in the south-eastern Amundsen Sea to include the ice conditions for both Pine Island Bay and around the Thwaites Ice Tongue. The ERA5 climatological 10-m wind (Hersbach et al., 2018) above the PIB and Thwaites gyres blows from the ice shelves to the ocean, with a speed decreasing from the southeast to the northwest. The maximum wind speed (10 m s-1) occurs in the southwestern corner of the model domain. The meridional gradient of wind speed (-1.667 × 10-6 s-1) is one-fifth of the zonal gradient of wind speed (-8.333 × 10-6 s-1). We vary the strength and sign of the wind stress curl to generate four wind forcing fields: strong or weak, cyclonic or anticyclonic wind stress curl. The average wind speed over the whole ocean model domain is kept the same for all four wind fields. Inside the main folder, there are five subfolders, - exp_ada_Flat: for the simulations with sea ice covering the top-left of the model domain, shown as "Seaice-\(\frac \pi2\)" - exp_ada_Topleft: for the simulations with sea ice covering the top-left side of the model domain, shown as "Seaice-\(\frac \pi4\)" - exp_ada_Topright: for the simulations with sea ice covering the top-right sideof the model domain, shown as "Seaice-\(\frac {3\pi}4\)" - exp_ada_Weaktopleft: for the simulations with sea ice covering the half part of the top-left side of the model domain, shown as "Seaice-\(\frac {3\pi}8\)" - exp_ada_Weaktopright: for the simulations with sea ice covering the half part of the top-right side of the model domain, shown as "Seaice-\(\frac {5\pi}8\)" - exp_ada_Discussion: for the simulations mentioned in the Discussion section, including those for the 1.5-layer baroclinic model (folders with "_grav" in the title, "grav" stands for the reduced gravity), for different widths of the marginal ice zone ("exp_MIZ") and for the model with a rectangle domain ("exp_rec"). Inside the subfolders, there are fourty-four subfolders, with the combination of the following components in the title that stand for different wind forcings, - Maxeast stands for "maximum wind speed occurs in the eastern side of the model domain", so "StrongCyclonic" - Maxwest stands for "maximum wind speed occurs in the western side of the model domain", so "StrongAnticyclonic" - Weakmaxeast stands for "maximum wind speed occurs in the eastern side of the model domain, but with a weaker wind stress curl", so "WeakAnticyclonic" - Weakmaxwest stands for "maximum wind speed occurs in the western side of the model domain, but with a weaker wind stress curl", so "WeakAnticyclonic" - numbers 0, 20, 40, ... 200 stand for the percentage of the wind stress that is transferred to the ocean through the sea ice. |
| Type Of Technology | Software |
| Year Produced | 2022 |
| Open Source License? | Yes |
| URL | https://zenodo.org/record/6757625 |
| Title | An Idealised Barotropic Ocean Gyre Model Code, Based on MITgcm |
| Description | This dataset is supplementary to The Cryosphere paper "Reversal of ocean gyres near ice shelves in the Amundsen Sea caused by the interaction of sea ice and wind". A full model description and the application can be found in the paper. Here is the modified version of the model set-up written in the paper in the chapter 3. This model is based on the MIT general circulation model (MITgcm; MITgcm's user manual 4.1; Marshall et al., 1997) with an idealised barotropic set-up. The model has an ocean domain with a size of 60 × 60 km and a horizontal grid spacing of 1 km. It has one 1-km-thick vertical layer with a free surface. All simulations are run for six model months, which allows all of them to spin up to be sufficiently close to a steady state. The spin-up time of the simulations varies from 51 days to 91 days, assessed as the time at which the daily change of the total kinetic energy of the ocean is less than 0.1% of the total kinetic energy of the ocean at the final model day of the 6 model months. The wind field is the only external forcing applied to the model ocean. We generate a simplified wind forcing field based on the key features of the climatological wind in the south-eastern Amundsen Sea to include the ice conditions for both Pine Island Bay and around the Thwaites Ice Tongue. The ERA5 climatological 10-m wind (Hersbach et al., 2018) above the PIB and Thwaites gyres blows from the ice shelves to the ocean, with a speed decreasing from the southeast to the northwest. The maximum wind speed (10 m s-1) occurs in the southwestern corner of the model domain. The meridional gradient of wind speed (-1.667 × 10-6 s-1) is one-fifth of the zonal gradient of wind speed (-8.333 × 10-6 s-1). We vary the strength and sign of the wind stress curl to generate four wind forcing fields: strong or weak, cyclonic or anticyclonic wind stress curl. The average wind speed over the whole ocean model domain is kept the same for all four wind fields. Inside the main folder, there are five subfolders, - exp_ada_Flat: for the simulations with sea ice covering the top-left of the model domain, shown as "Seaice-\(\frac \pi2\)" - exp_ada_Topleft: for the simulations with sea ice covering the top-left side of the model domain, shown as "Seaice-\(\frac \pi4\)" - exp_ada_Topright: for the simulations with sea ice covering the top-right sideof the model domain, shown as "Seaice-\(\frac {3\pi}4\)" - exp_ada_Weaktopleft: for the simulations with sea ice covering the half part of the top-left side of the model domain, shown as "Seaice-\(\frac {3\pi}8\)" - exp_ada_Weaktopright: for the simulations with sea ice covering the half part of the top-right side of the model domain, shown as "Seaice-\(\frac {5\pi}8\)" - exp_ada_Discussion: for the simulations mentioned in the Discussion section, including those for the 1.5-layer baroclinic model (folders with "_grav" in the title, "grav" stands for the reduced gravity), for different widths of the marginal ice zone ("exp_MIZ") and for the model with a rectangle domain ("exp_rec"). Inside the subfolders, there are fourty-four subfolders, with the combination of the following components in the title that stand for different wind forcings, - Maxeast stands for "maximum wind speed occurs in the eastern side of the model domain", so "StrongCyclonic" - Maxwest stands for "maximum wind speed occurs in the western side of the model domain", so "StrongAnticyclonic" - Weakmaxeast stands for "maximum wind speed occurs in the eastern side of the model domain, but with a weaker wind stress curl", so "WeakAnticyclonic" - Weakmaxwest stands for "maximum wind speed occurs in the western side of the model domain, but with a weaker wind stress curl", so "WeakAnticyclonic" - numbers 0, 20, 40, ... 200 stand for the percentage of the wind stress that is transferred to the ocean through the sea ice. |
| Type Of Technology | Software |
| Year Produced | 2022 |
| Open Source License? | Yes |
| URL | https://zenodo.org/record/6757626 |
| Description | ITGC launch press |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Media (as a channel to the public) |
| Results and Impact | Press releases for the beginning of the ITGC. Many interviews with radio, TV (BBC News), print media and online media. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Talk at Icemap Workshop |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Introduction to tidal forces in the context of ice shelf fracturing. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Talk at TARSAN-ARTEMIS Oceans Workshop |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Overview of Autosub Long Rang (ALR) missions during NBP22-02. |
| Year(s) Of Engagement Activity | 2023 |