Wed 23 Sep 16:00: Observing Iceberg Melt in a Greenland Fjord The talk will be online. Contact the host to get Zoom details.
As much as half of the freshwater flux from the Greenland Ice Sheet enters the ocean through iceberg calving. Up to 50% of iceberg mass is expected to melt within glacial fjords, where it influences the circulation and properties of water masses in contact with the glacier terminus, as well as the characteristics of glacially-modified water exported to the North Atlantic. Observations of iceberg melt in fjords are needed to evaluate predictions of spatial and temporal meltwater distribution under a range of environmental conditions, in order to determine its impacts on the ocean.
We conducted repeat oceanographic surveys of 6 icebergs in Sermilik Fjord, southeast Greenland, during August 2018 to identify environmental factors driving the distribution of iceberg melt, including ocean thermal forcing and stratification, relative velocity between each iceberg and local ocean currents, and iceberg geometry. Our surveys include near-iceberg properties sampled using a remotely-operated surface vehicle (Jetyak) equipped with an ADCP (Acoustic Doppler Current Profiler) and temperature and salinity sensors, as well as full-depth temperature and salinity profiles. Iceberg depth and shape were measured using multibeam sonar and aerial imagery, and some iceberg locations were tracked with GPS . We compare our findings to numerical and laboratory simulations, and discuss their implications for iceberg melt distribution in the context of a decade-long observational record of ocean variability in Sermilik Fjord.
The talk will be online. Contact the host to get Zoom details.
- Speaker: Margaret Lindeman, Scripps Institution of Oceanography
- Wednesday 23 September 2020, 16:00-17:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 09 Sep 15:00: Arctic Freshwater Storage and Export in CMIP6 Models The talk will be online. Contact the host to get Zoom details.
Recently, the Arctic has undergone substantial changes in sea ice cover and the hydrologic cycle, both of which strongly impact the freshwater storage in, and export from, the Arctic Ocean. The fate of Arctic Ocean freshwater (FW) is of global relevance, as it can impact North Atlantic Deep Water formation and potentially the strength of the Meridional Overturning Circulation. Here we analyze Arctic FW storage and export in 7 climate models from the Coupled Model Intercomparison Project phase 6 (CMIP6) and assess their agreement over the historical period (1980-2000) and in two future emissions scenarios, SSP1 -2.6 and SSP5 -8.5. Rather than focusing on a single realization of each experiment, ensembles from each model are used in order to understand model internal variability and to better constrain inter-model differences.
In both future scenarios the models show an increase in liquid (ocean) freshwater storage that is partially due to a reduction in solid (ice) storage through sea ice melt. This reduction in sea ice coverage also leads to a reduction in solid fluxes through the five major Arctic gateways (Bering Strait, Fram Strait, Nares Strait, Barrow Strait, and the Barents Sea Opening) that is typically larger for SSP5 -8.5 than SSP1 -2.6. The liquid fluxes through the gateways exhibit a more complex pattern, with some models showing a change in sign of the freshwater flux through the Barents Sea Opening, for example. To identify the mechanisms responsible for such changes, the ocean fluxes are decomposed into their salinity and volume contributions. Although the models broadly agree on the sign of the storage and flux changes, substantial differences exist between the magnitude of these changes and the models’ underlying mean states.
The talk will be online. Contact the host to get Zoom details.
- Speaker: Hannah Zanowski, University of Colorador Boulder
- Wednesday 09 September 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 02 Dec 10:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Madi Rosevear, University of Tasmania
- Wednesday 02 December 2020, 10:00-11:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 18 Nov 16:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Georgy Manucharyan, University of Washington
- Wednesday 18 November 2020, 16:00-17:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 04 Nov 15:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Luwei Yang, University of California, Los Angeles
- Wednesday 04 November 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Shenjie Zhou.
Wed 21 Oct 14:00: Seasonal prediction and predictability of regional Antarctic sea ice The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Mitch Bushuk, Geophysical Fluid Dynamics Laboratory
- Wednesday 21 October 2020, 14:00-15:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 07 Oct 14:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Rebecca Jackson, Rutgers University
- Wednesday 07 October 2020, 14:00-15:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 23 Sep 16:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Margaret Lindeman, Scripps Institution of Oceanography
- Wednesday 23 September 2020, 16:00-17:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 09 Sep 15:00: TBD The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Hannah Zanowski, University of Colorador Boulder
- Wednesday 09 September 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Irena Vankova.
Wed 02 Dec 10:00: TBD
Abstract not available
- Speaker: Madi Rosevear, University of Tasmania
- Wednesday 02 December 2020, 10:00-11:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: irkova.
Wed 18 Nov 16:00: TBD
Abstract not available
- Speaker: Georgy Manucharyan, University of Washington
- Wednesday 18 November 2020, 16:00-17:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: irkova.
Wed 04 Nov 15:00: TBD
Abstract not available
- Speaker: Luwei Yang, University of California, Los Angeles
- Wednesday 04 November 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: irkova.
Wed 08 Jul 10:00: Influences of Melt Water from Sea Ice/Ice Shelf in Polar Oceans The talk will be online. Contact the host to get Zoom details.
Fresh melt water from sea ice and ice shelf is not only essential to the ocean hydrography but the mesoscale dynamics due to the induced baroclinicity. Warm intrusions from the Bering Strait transport heat and nutrients via baroclinic eddies vertically beneath the sea ice and laterally across structural fronts near the ice edge in the eastern Chukchi Sea. Numerical models using the Regional Ocean Model System (ROMS) are integrated to systematically investigate the importance of the baroclinic eddy field and the factors that affect its dynamics, specifically on the stratifications determined by the fresh water volume. Model results show a noticeable effect of strong wind events on ice edge displacement. The advection of ice away from or toward the inflow changes the ice melt rate and the salinity of the melt water plume, both are the factors that important to the heat transported by baroclinic instability and further feedback to the ice melt rate. Similar mechanisms can be found elsewhere around the ice fronts of sea ice and ice shelves,it is worth studying with more systematically models of the other regional oceans to explore the coincidences and dissimilarities.
The talk will be online. Contact the host to get Zoom details.
- Speaker: Kofan Lu, JAMSTEC
- Wednesday 08 July 2020, 10:00-11:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Wed 15 Jul 16:00: Ikaaġvik Sikukun: Bridging the Scientific and Indigenous Communities to Study Sea Ice Change in Arctic Alaska The talk will be online. Contact the host to get Zoom details.
Taking its name from the Iñupiaq phrase for “ice bridge” the Ikaaġvik Sikukun project has successfully built bridges between a diverse team of scientists and Indigenous Knowledge-holders to study the changing sea-ice environment of Kotzebue Sound, Alaska. We have broken new ground by co-producing our hypotheses in partnership with an Indigenous Elder advisory council to develop research questions that cut across disciplinary boundaries and address the needs of both the local and scientific communities. To share our story broadly and in a way that respects the oral traditions of Indigenous Knowledge, our team also includes an ethnographic film-maker who has been documenting each step of our unique research journey. Over the past three years, with continued guidance from our advisory council, we have designed and carried out a research plan to observe the sea ice and marine mammals in Kotzebue Sound and how these come together as habitat and hunting grounds. Using satellite data, unmanned aerial systems (UAS), oceanographic moorings and on-ice measurements we have witnessed two exceptional years (2018 and 2019) with unprecedentedly low sea ice extent and the earliest start of bearded seal (Erignathus barbatus) hunting in recent memory – contributing to a broader trend towards shorter spring hunting seasons, which have been recorded in Kotzebue since 2003. We also observed widespread flooding of the landfast ice, possibly caused by relatively high snowfall on top of thin ice, as well as the detachment and fragmentation of landfast ice recently occupied by ringed seal (Phoca hispida) pups, adults, and their lairs. Having integrated Indigenous Knowledge throughout our approach, we are now in a unique position to turn these interrelated observations into answers to our research questions. Join the diverse Ikaaġvik Sikukun team as I share an overview of our research approach and preliminary results including observations of the sea ice heat budget that undergoes a rapid change during Spring melt and breakup, as well as the profound impact of sea ice change on the traditional use of these regions by local indigenous Iñupiaq populations.
Team: Andrew R. Mahoney, Sarah Betcher, Donna Hauser, Ajit Subramaniam, Alex Whiting, John Goodwin, Cyrus Harris, Robert Schaeffer, Ross Schaeffer, Nathan Laxague, Jessica Lindsay, Carson Witte
The talk will be online. Contact the host to get Zoom details.
- Speaker: Christopher J. Zappa, Lamont-Doherty Earth Observatory, Columbia University
- Wednesday 15 July 2020, 16:00-17:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Thu 23 Jul 11:00: Ice melt driven by the ocean - Two process studies on the physics of ice-ocean interactions based on observations from NE Greenland and the central Arctic Ocean The talk will be online. Contact the host to get Zoom details.
Part I: Rapid supply of warm Atlantic waters below Greenland’s largest glacier tongue
Mass loss from the Greenland ice sheet has increased over the past two decades, currently accounting for 25% of global sea level rise. This is due to increased surface melt driven by atmospheric warming and the retreat and acceleration of marine terminating glaciers forced by oceanic heat transport. We use ship-based profiles, bathymetric data and moored time series from 2016 to 2017 of temperature, salinity and water velocity collected in front of the floating tongue of the 79 North Glacier in Northeast Greenland. These observations indicate that a year-round bottom-intensified inflow of warm Atlantic Water through a narrow channel is constrained by a sill. The associated heat transport leads to a mean melt rate of 10.4 ± 3.1 m yr–1 on the bottom of the floating glacier tongue. We conclude that near-glacier, sill-controlled ocean heat transport plays a crucial role for glacier stability.
Part II: Trapped in the Arctic ice – First results from the MOS AiC expedition (leg 3)
MOS AiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) aims at a breakthrough in understanding the Arctic climate system and in its representation in global climate models. The backbone of MOS AiC is the year-round operation of RV Polarstern, drifting since October 2019 with the sea ice across the central Arctic. A distributed regional network of observational sites has been set up on the sea ice in an area of up to ~40 km distance from RV Polarstern. Team OCEAN aims at a better understanding of ocean boundary-layer mixing processes and heat fluxes from the warm Atlantic water across the halocline. On leg 3, all teams carried out measurements during the transition from 24-hours darkness to 24-hours light. Furthermore, we sampled in newly formed leads and ridges, during the passage of storms, and captured the onset of the melting season – under challenging work conditions.
The talk will be online. Contact the host to get Zoom details.
- Speaker: Dr Janin Schaffer, Alfred Wegener Institute, Germany
- Thursday 23 July 2020, 11:00-12:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Thu 02 Jul 15:00: ROSETTA-Ice: a new framework for understanding the Ross Ice Shelf The talk will be online. Contact the host to get Zoom details.
See abstract at https://www.nature.com/articles/s41561-019-0370-2?draft=collection
The talk will be online. Contact the host to get Zoom details.
- Speaker: Kirsty Tinto, Lamont-Doherty Earth Observatory
- Thursday 02 July 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Wed 08 Jul 10:00: Influences of Melt Water from Sea Ice/Ice Shelf in Polar Oceans The talk will be online. Contact the host to get Zoom details.
Fresh melt water from sea ice and ice shelf is not only essential to the ocean hydrography but the mesoscale dynamics due to the induced baroclinicity. Warm intrusions from the Bering Strait transport heat and nutrients via baroclinic eddies vertically beneath the sea ice and laterally across structural fronts near the ice edge in the eastern Chukchi Sea. Numerical models using the Regional Ocean Model System (ROMS) are integrated to systematically investigate the importance of the baroclinic eddy field and the factors that affect its dynamics, specifically on the stratifications determined by the fresh water volume. Model results show a noticeable effect of strong wind events on ice edge displacement. The advection of ice away from or toward the inflow changes the ice melt rate and the salinity of the melt water plume, both are the factors that important to the heat transported by baroclinic instability and further feedback to the ice melt rate. Similar mechanisms can be found elsewhere around the ice fronts of sea ice and ice shelves,it is worth studying with more systematically models of the other regional oceans to explore the coincidences and dissimilarities.
The talk will be online. Contact the host to get Zoom details.
- Speaker: Kofan Lu, JAMSTEC
- Wednesday 08 July 2020, 10:00-11:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Thu 02 Jul 15:00: ROSETTA-Ice: a new framework for understanding the Ross Ice Shelf The talk will be online. Contact the host to get Zoom details.
Abstract not available
The talk will be online. Contact the host to get Zoom details.
- Speaker: Kirsty Tinto, Lamont-Doherty Earth Observatory
- Thursday 02 July 2020, 15:00-16:00
- Venue: British Antarctic Survey, Zoom.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Louis Couston.
Mon 29 Jun 14:00: Atmospheric Chemistry Experiment (ACE): Mission overview and latest results
ACE is a science mission measuring atmospheric composition by solar occultation from low Earth orbit (http://www.ace.uwaterloo.ca/). The primary instrument is an infrared Fourier transform spectrometer (ACE-FTS) that provides atmospheric transmission spectra from the troposphere to the lower thermosphere. ACE -FTS version 4.0 processing yields volume mixing ratio (VMR) altitude profiles for more than 40 molecules and 20 isotopologues as well as atmospheric extinction from two imagers. After more than 16 years on orbit, ACE data are diagnostic for climate change observations. Topics covered will include measurements of tropospheric and mesospheric CO2 , gases associated with the Montreal Protocol, fire emissions, volcanic eruptions and polar mesospheric clouds
- Speaker: Prof. Peter Bernath - University of Waterloo
- Monday 29 June 2020, 14:00-15:00
- Venue: Venue to be confirmed.
- Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: .