About
The Scripps Polar Seminar is a fortnightly seminar series focusing on any subject relating to high latitude and/or cryosphere research. Topics are wide-ranging, from the commercial realities of Arctic oil and gas reserves (David G. Victor, UCSD) to the applicability of a sliding law to the Antarctic ice sheet (Slawek Tulaczyk, UCSC). Information about upcoming seminars is sent out via the SIO Polar listserv, which you can join here. If you would like to add the Polar Seminar calendar to your Google Calendar, please click here.
We are always looking for new speakers! If you are interested in giving a 30-45 minute talk about your polar research, please use the contact form below to get in touch with the seminar organizer.
The Scripps Polar Seminar is a fortnightly seminar series focusing on any subject relating to high latitude and/or cryosphere research. Topics are wide-ranging, from the commercial realities of Arctic oil and gas reserves (David G. Victor, UCSD) to the applicability of a sliding law to the Antarctic ice sheet (Slawek Tulaczyk, UCSC). Information about upcoming seminars is sent out via the SIO Polar listserv, which you can join here. If you would like to add the Polar Seminar calendar to your Google Calendar, please click here.
We are always looking for new speakers! If you are interested in giving a 30-45 minute talk about your polar research, please use the contact form below to get in touch with the seminar organizer.
Schedule
Welcome back for the Spring Quarter! Polar Seminars will take place at 2PM every other Tuesday. We're switching rooms to Hubbs 4500 for this quarter. We still have some slot opens, so if you would like to give a seminar or know someone who should, email the Polar Seminar organizers, Sarah ([email protected]) and Susheel ([email protected]), and we'll get working on it.
April 4
Location: Revelle 4301
Derek Mueller
Associate Professor, Carleton University
Arctic ice shelves, epishelf lakes and basal channels
Arctic ice shelves in Canada are derived from thick coastal landfast sea ice along with glacial input in some places. These large ice features are not as extensive or as thick as Antarctic ice shelves but they represent the oldest (~1,400 – 5,000 years old) and thickest sea ice in the world. Over the course of the last hundred years, the Canadian ice shelves along the northern coast of Ellesmere Island have been reduced to 535 km2 from over 8,597 km2 (94% loss). This occurred over a period of pronounced atmospheric warming and created many large ice islands (extensive tabular icebergs) that drifted up to decades around the Arctic Ocean. Arctic ice shelves, like some of their Antarctic counterparts, have caused freshwater lakes to form to their landward sides by impounding a layer of meltwater that floats over the ocean. These so-called epishelf lakes have also changed dramatically as their ice shelf dams thinned and broke-up. Some of these lakes, which contain relatively warm water, have incised basal channels in the ice shelves that block them. We are investigating how the fate of ice shelves and epishelf lakes are intertwined along with the processes that may eventually destabilize the ice shelves and trigger break-up.
May 9
Eddie Kisfaludy and Amanda Kisfaludy, SciFly, LLC
Helicopter Footage of Greenland, Iceland, and Faroe Islands During 2016 Record Breaking Warm Summer
Gyrostabilized high definition aerial video of southern Greenland, Iceland, and the Faroe Islands was captured using a small helicopter during a 30-day westbound transatlantic flight in August of 2016 across the North Atlantic. Focus will be on presenting rare oblique views of shorelines and interior regions, highlighting calving fronts, melt pools, moulins, ice sheet, fjords, bays, and lagoons to provide the audience with a general overview of these wild and rarely photographed landscapes.
May 18
Jeremy Bassis
Associate Professor, Carleton University
Bound to rise: Constraints on the rate of sea level rise from the past and present behavior of ice sheets
Observations show that portions of ice sheets in contact with the ocean can respond rapidly to both atmospheric and oceanic warming. This has been dramatically illustrated during the last glacial period when the Laurentide Ice Sheet sporadically discharged vast armadas of icebergs through the Hudson Strait into the North Atlantic Ocean during so-called Heinrich Events. More recently, we have observed punctuated ice sheet decay during the unexpectedly catastrophic disintegration of ice shelves on the Antarctic Peninsula and during the (also unpredicted) retreat of marine terminating glaciers surrounding the Greenland Ice Sheet. Attempts to incorporate the processes responsible for these disparate phenomena into ice sheet models have led to diverging projections of sea level rise with the most dire projection hinting that large portions of the West Antarctic Ice Sheet could collapse on century time scales through a newly recognized effect called the `marine ice cliff instability’. The marine ice cliff instability is based on the idea that the finite strength of ice places a limit on the maximum ice cliff height possible at the ice sheet terminus; when this height is broached, catastrophic ice sheet disintegration can occur. Here, we examine the theoretical and observational basis for the marine ice cliff instability to show that the observations of Greenland, Svalbard and Alaskan glaciers are broadly consistent with the `upper bound’ on ice cliff height suggested by theory. We further show that this model can explain large-scale patterns of glacier advance and retreat and—subject to idealized forcing—even Heinrich Events. Applying the model to modern ice sheet configurations, we find that large-scale ice sheet stability depends sensitively on the rate of isostatic adjustment of the bed, which is controlled by the viscosity structure of the upper mantle. Seismic inference of the viscosity of the mantle beneath the sections of West Antarctic Ice Sheet most prone to collapse suggests a low mantle viscosity, implying a rapid uplift rate following retreat. This effect is a significant stabilizing effect that can not only arrest ice sheet retreat, but also lead to subsequent re-advance. This suggests that solid Earth structure may play an unexpectedly large role in century time scale projections of sea level rise and climate change.
May 23
Laurie Padman
Earth and Space Research, Oregon
Click here for a list of previous Polar Seminars
Welcome back for the Spring Quarter! Polar Seminars will take place at 2PM every other Tuesday. We're switching rooms to Hubbs 4500 for this quarter. We still have some slot opens, so if you would like to give a seminar or know someone who should, email the Polar Seminar organizers, Sarah ([email protected]) and Susheel ([email protected]), and we'll get working on it.
April 4
Location: Revelle 4301
Derek Mueller
Associate Professor, Carleton University
Arctic ice shelves, epishelf lakes and basal channels
Arctic ice shelves in Canada are derived from thick coastal landfast sea ice along with glacial input in some places. These large ice features are not as extensive or as thick as Antarctic ice shelves but they represent the oldest (~1,400 – 5,000 years old) and thickest sea ice in the world. Over the course of the last hundred years, the Canadian ice shelves along the northern coast of Ellesmere Island have been reduced to 535 km2 from over 8,597 km2 (94% loss). This occurred over a period of pronounced atmospheric warming and created many large ice islands (extensive tabular icebergs) that drifted up to decades around the Arctic Ocean. Arctic ice shelves, like some of their Antarctic counterparts, have caused freshwater lakes to form to their landward sides by impounding a layer of meltwater that floats over the ocean. These so-called epishelf lakes have also changed dramatically as their ice shelf dams thinned and broke-up. Some of these lakes, which contain relatively warm water, have incised basal channels in the ice shelves that block them. We are investigating how the fate of ice shelves and epishelf lakes are intertwined along with the processes that may eventually destabilize the ice shelves and trigger break-up.
May 9
Eddie Kisfaludy and Amanda Kisfaludy, SciFly, LLC
Helicopter Footage of Greenland, Iceland, and Faroe Islands During 2016 Record Breaking Warm Summer
Gyrostabilized high definition aerial video of southern Greenland, Iceland, and the Faroe Islands was captured using a small helicopter during a 30-day westbound transatlantic flight in August of 2016 across the North Atlantic. Focus will be on presenting rare oblique views of shorelines and interior regions, highlighting calving fronts, melt pools, moulins, ice sheet, fjords, bays, and lagoons to provide the audience with a general overview of these wild and rarely photographed landscapes.
May 18
Jeremy Bassis
Associate Professor, Carleton University
Bound to rise: Constraints on the rate of sea level rise from the past and present behavior of ice sheets
Observations show that portions of ice sheets in contact with the ocean can respond rapidly to both atmospheric and oceanic warming. This has been dramatically illustrated during the last glacial period when the Laurentide Ice Sheet sporadically discharged vast armadas of icebergs through the Hudson Strait into the North Atlantic Ocean during so-called Heinrich Events. More recently, we have observed punctuated ice sheet decay during the unexpectedly catastrophic disintegration of ice shelves on the Antarctic Peninsula and during the (also unpredicted) retreat of marine terminating glaciers surrounding the Greenland Ice Sheet. Attempts to incorporate the processes responsible for these disparate phenomena into ice sheet models have led to diverging projections of sea level rise with the most dire projection hinting that large portions of the West Antarctic Ice Sheet could collapse on century time scales through a newly recognized effect called the `marine ice cliff instability’. The marine ice cliff instability is based on the idea that the finite strength of ice places a limit on the maximum ice cliff height possible at the ice sheet terminus; when this height is broached, catastrophic ice sheet disintegration can occur. Here, we examine the theoretical and observational basis for the marine ice cliff instability to show that the observations of Greenland, Svalbard and Alaskan glaciers are broadly consistent with the `upper bound’ on ice cliff height suggested by theory. We further show that this model can explain large-scale patterns of glacier advance and retreat and—subject to idealized forcing—even Heinrich Events. Applying the model to modern ice sheet configurations, we find that large-scale ice sheet stability depends sensitively on the rate of isostatic adjustment of the bed, which is controlled by the viscosity structure of the upper mantle. Seismic inference of the viscosity of the mantle beneath the sections of West Antarctic Ice Sheet most prone to collapse suggests a low mantle viscosity, implying a rapid uplift rate following retreat. This effect is a significant stabilizing effect that can not only arrest ice sheet retreat, but also lead to subsequent re-advance. This suggests that solid Earth structure may play an unexpectedly large role in century time scale projections of sea level rise and climate change.
May 23
Laurie Padman
Earth and Space Research, Oregon
Click here for a list of previous Polar Seminars