Collaborative Research: Uncertainty and Mechanisms of Antarctica’s Changing Snowfall and its Role in Sea Level Change
Start Date:
2020-08-01
End Date:
2024-07-31
Description/Abstract
The Antarctic Ice Sheet (AIS) is sensitive to and an indicator of climate change. While ice loss is largely driven by ocean warming, this might be mitigated by enhanced snowfall on the ice sheet. By developing an understanding of the processes governing snowfall variability and change on the AIS, this project will contribute to understanding the long-term role of the AIS as a contributor to sea-level rise. This project is strongly embedded in the collaborative, open-source framework of the Community Earth System Model version 2 (CESM2) and will deliver new datasets of Antarctic precipitation for use by the research community. The project will help to build a diverse geoscience workforce by recruiting and training a student to be directly involved in the research through the Significant Opportunities in Atmospheric Research and Science (SOARS) program. The project will leverage the Climate Model Intercomparison Project 6 climate model ensemble as a whole, and CESM2 in particular, to disentangle the major sources of uncertainty and to elucidate the underlying mechanisms of Antarctic precipitation change, with a particular focus on the role of atmospheric circulation changes relative to the role of atmospheric warming. Using the variable resolution capabilities of CESM2, the team will provide the community with precipitation estimates at a very high horizontal resolution. The analyses will also use a forthcoming 100-member large ensemble. The project seeks to answer the following questions: 1) How well does the CESM2 represent the present-day Antarctic surface climate, precipitation, and surface mass balance, including the mean and its variability? 2) What is the sensitivity of simulated Antarctic precipitation to model resolution in present-day and future climates? 3) What are the roles of thermodynamics (warming atmosphere and ocean) and dynamics (changes in atmospheric circulation) in observed and projected snowfall changes? How do these break down into forced and internal variability? In particular, is there a significant forced precipitation trend due to circulation changes driven by stratospheric ozone depletion and recovery and increases in greenhouse gas concentration? 4) What processes and boundary conditions drive the ensemble spread of Antarctic precipitation in single-model and multi-model ensembles? How does the spread driven by initial surface conditions (including sea ice cover, surface fluxes, inversion strength) compare with the irreducible uncertainty due to internal climate system variability? This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Personnel
Funding
AMD - DIF Record(s)
Data Management Plan
None in the Database
Product Level:
4 (model output and interpretations)
Datasets
Publications
Keywords
Platforms and Instruments
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