Tag: David Sutherland

Controls on glacial retreat in the West Antarctic Peninsula

Presenter(s): Ryan Obermeyer − Math, Spatial Data Science And Technology

Faculty Mentor(s): David Sutherland, Kiya Riverman

Poster 52

Research Area: Physical Science

Funding: NSF grant no. 1543012

The West Antarctic Peninsula has over 300 glaciers, all with unique environmental conditions. The peninsula is losing ice, but it is not fully understood what drives retreat rates for individual glaciers. The Antarctic Peninsula is rich in available data, but comparatively little analysis of glacial environmental controls has been performed. We used a Landsat-7 and laser altimetry derived grounding line, infrared temperature data, bathymetry swath data, Regional Ocean Modeling runs, and calculated retreat rates to find correlations between retreat and environment. Previous work has shown that glaciers in the region are sensitive to ocean temperatures. Glaciers in the northern portion of the peninsula interact with cooler ocean currents and have lower retreat rates than the glaciers in the south. We found a latitudinal cut off, north of which floating glaciers rarely exist. Warmer air temperatures in the northern portion of the peninsula may limit the prevalence of floating glaciers. In contrast, the south with cooler air and warmer water allows glaciers to interact with the ocean. Model runs of Circumpolar Deep Water flow highlight which glaciers are in contact with warmer water. There is correlation between glacial retreat and contact with Circumpolar Deep Water. These findings allow us to predict that as air temperatures in Antarctica continue to rise, the latitudinal cut off for floating glaciers could move south, and less ice will be interacting with the ocean. This means that there is potential for retreat rates to temporarily decline as glaciers will be less affected by ocean temperatures.

Quantifying Ocean Dynamics through Iceberg Tracking in Ilulissat Fjord

Presenter(s): Richelle Ann Cabatic − Physics

Faculty Mentor(s): David Sutherland, Kristin Schild

Poster 2

Research Area: Natural/Physical Sciences

Funding: NSF Iceberg Grant – Sutherland Lab

When Greenland’s tidewater glaciers reach the ocean, they break off numerous icebergs into fjords. These icebergs travel through the fjord and out into the ocean. All the while different types of water circulate through the fjord, meeting with the glacier’s terminus and affecting it’s stability. The tidewater glacier, Jakobshavn Isbrae, and it’s accompanying fjord, Ilulissat Fjord, is of particular interest due to its very active export of icebergs. Many studies have addressed Jakobshavn’s glacial front, but little is known about Ilulissat’s ocean circulation due to the difficulty of collecting field measurements in the ice-choked region. Through our study, we deploy transmitting GPS units on icebergs in Ilulissat Fjord, thereby tracking iceberg movement and, in part, the region’s ocean circulation. Using icebergs as proxies for surface circulation thus provides an alternative to deploying marine instruments that have minimal likelihood for survival in the treacherous fjord environment. Preliminary results of our study show that: at a distance of 35km away from the glacier terminus, iceberg movement is no longer dominated by glacial calving events; there are eddy circulation patterns at fjord widening locations; and, that the studied icebergs move at an average speed of 0.8 km/hr. This study has the potential to help oceanographers and engineers learn more about the Ilulissat system’s circulation dynamics, and inform glaciologists about how Jakobshavn Glacier melt rates and acceleration is affected by the circulation.

Estuary Coastline Change over a century in the Coos Bay, Oregon

Presenter(s): Kira Bartlett − Earth Science, Geography

Faculty Mentor(s): David Sutherland, Patricia McDowell

Oral Session 4CS

Research Area: Natural/Physical Science

Coos Bay Estuary is the largest bay between San Francisco and Puget Sound. The estuary serves an important role in the region’s economic prosperity through transportation and agriculture. The purpose was to study the Coos Bay Estuary coastline change through the years 1895 through 2011 and determine the human and natural influences causing the changes. Historic NOAA maps were georeferenced into ArcGIS and analyzed by altering shapefiles of the estuary shoreline the years using for each selected map. Comparison maps, area change charts, and shoreline distance verses time graph were used to demonstrate the major changes. The changes were compared to a historical events timeline for the region of Coos Bay to show the correlation. The major changes on the estuary shoreline are a result of the local airport construction, and other areas that were heavily influenced by human alteration and influence. Between the years 1953 and 1940 the estuary was the most heavily altered. Only a minimal amount of the shoreline changes shows evidence of natural causes, such as erosion. With this information, the City of Coos Bay can decide on what preservation or alterations they feel are necessary to maintain the economic benefits of the estuary.

Environmental controls on glacial thinning along the West Antarctic Peninsula.

Presenter(s): Ryan Obermeyer

Faculty Mentor(s): David Sutherland & Kiya Riverman

Poster 8

Session: Sciences

The West Antarctic Peninsula holds over 300 glaciers, all with unique environmental conditions. The peninsula is losing ice, but it is not fully understood what determines change for individual glaciers. Fortunately, Antarctica is rich in remotely sensed data. We use a suite of remotely sensed data to determine environmental controls on glacier retreat and thinning. Using Landsat- 7 and laser altimetry derived grounding lines, infrared temperature data, bathymetry swath data, Regional Ocean Modeling runs, and calculated retreat rates we have found more specific correlations between retreat and environment. Furthermore, the creation of the Reference Elevation Model for Antarctica (REMA) allowed for an opportunity to further our understanding of these systems with thinning rates. REMA is a 2m resolution elevation data base for Antarctica from 2009 through 2017. Here we calculate elevation change over time for the West Antarctica Peninsula from REMA. With these rates, we can spatially see how ice is changing on a 2m by 2m scale. We find that glaciers are sensitive to ocean temperature and are directly affected by Antarctic currents, and glaciers with floating tongues have potential for faster retreat. Glaciers in the southern portion of the West Antarctic Peninsula are retreating faster than glaciers in the north.

Quantifying upper layer ocean dynamics using iceberg GPS Tracking

Presenter(s): Richelle Ann Cabatic

Faculty Mentor(s): Kristin Schild & David Sutherland

Oral Session 2 M

The Greenland proglacial fjord system, where glaciers from the ice sheet reach the ocean, is an important contributor to sea level rise. When reaching the ocean, these glaciers break off icebergs. These icebergs travel through the fjord and out into the open ocean. All the while, different types of water circulate through the fjord, meeting with the glacier’s terminus and affecting it’s stability. The tidewater glacier, Jakobshavn Isbrae, and it’s fjord, Ilulissat, is of particular interest because it is the most prolific glacial system in Greenland in terms of ice export. Many studies have addressed Jakobshavn’s glacial front, but little is known about Ilulissat’s ocean circulation due to the difficulty of collecting field measurements in the ice-choked region. Through our study, we deploy transmitting GPS units on icebergs in Ilulissat Fjord, thereby directly tracking iceberg movement and indirectly detecting the fjord’s circulation patterns. Using icebergs as proxies for surface circulation thus provides an alternative to deploying marine instruments that have minimal likelihood for survival in the treacherous fjord environment. Results of our study show that: at a distance of 35km away from the glacier terminus, iceberg movement is no longer dominated by glacial calving events; and that there are eddy circulation patterns at fjord widening locations. This study has the potential to help oceanographers understand more about Ilulissat’s circulation dynamics, and can inform glaciologists about how glaciers such as Jakobshavn’s acceleration is affected by this type of circulation.