[pccgrads] APL seminar Monday March 25th 10am -- Jessica Badgeley -- Seasonality in ice-flow dynamics

[Aaron Donohoe]

Jessica Badgeley is a finalist for the APL Science + Engineering Enrichment
+ Development (SEED) Postdoctoral Fellowship and will be giving a seminar
on Monday March 25th at 10am in the APL Henderson Hall Commons.  The
Henderson Hall commons are open to anyone at UW, no badge required. The
Eastern doorway to Handerson will be open from 9:30 am onward and the
Commons are just to your right when you walk in the building. Feel free to
contact me with access questions. Refreshments (coffee and pastries) will
be served prior to the seminar -- please come socialize before the seminar.

*Title: Seasonality in ice-flow dynamics of Greenland outlet glaciers:
Impact on ice sheet mass balance at present and in the future*


*Time/location: Monday March 25, 10am. Henderson Commons *


*Remote option: Live zoom link to follow*


*Abstract:* State-of-the-art ice sheet model simulations used in the Ice
Sheet Model Intercomparison Project (ISMIP) are inconsistent with recent
observations of ice sheet change. For Greenland, models tend to
underestimate the observed cumulative mass balance over the last several
decades, calling into question the accuracy of current projections of the
ice sheet’s contribution to sea level rise. Most models only resolve ice
dynamics at annual to coarser resolution, and therefore seasonal
variability in outlet glacier flow may be an unresolved critical driver of
present and future mass balance of the Greenland Ice Sheet and a remaining
source of the model-observation discrepancy. Previous research that has
examined seasonal glacier dynamics in Greenland shows that both ice front
positions and subglacial hydrology determine sub-annual dynamic
variability. Studies that relate these variables, however, rely on
idealized models, observations only, or are limited to individual or small
samples of glaciers. These caveats have made it challenging to quantify
causal linkages between processes and seasonal glacier dynamics and have
limited our understanding of how this seasonality will impact the net mass
balance of glaciers and the ice sheet in the future. In this talk, I will
discuss current and proposed work that uses a transient data assimilation
approach to constrain a spatially and temporally complete accounting of the
dominant drivers of Greenland outlet glacier seasonality. With these
data-constrained model results, I will show how dynamic seasonality
impacted historical ice sheet mass balance. Projecting future impacts of
seasonal ice dynamics, however, will require creating parameterizations of
these processes. I will work towards parameterizations by first using my
numerical model results along with dense observations to understand which
environmental and geometric factors determine the spatiotemporal
variability of seasonal dynamic drivers. In addition, the model-data
integration framework developed during this project will naturally extend
to other transient ice dynamic questions for both the Greenland and
Antarctic ice sheets.
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