Observations indicate that the greenland and antarctic ICE sheet have contributed approximately 7.5 MM and 4 MM respectively to global sea level rise over the 1992-2011 period, and that their…

This federal contract award is a $204,207.56 grant to the University of Texas at Austin (UT Austin) from the National Aeronautics and Space Administration (NASA) Shared Services Center. The grant supports continued development of coupling efforts between ice sheet models and NASA's GEOS-5 and GISS ModelE climate models. The goal is to gain insights into the effects of dynamic ice sheets and associated feedbacks on the global climate system. Specifically, the research will focus on improving parameterizations of melt rates beneath floating ice shelves and generalizing them for use in coupling ice sheet and global ocean models. The grant will explore the ability to hindcast mass loss rates observed by the GRACE satellite mission and assess impacts of freshwater flux on North Atlantic circulation and Antarctic sea ice extent. This grant does not have a set-aside designation. UT Austin is the prime grantee, as part of the University of Texas System, a state university system focused on higher education, research, and healthcare.

Observations indicate that the greenland and antarctic ICE sheet have contributed approximately 7.5 MM and 4 MM respectively to global sea level rise over the 1992-2011 period, and that their contribution to sea level rise is accelerating. Sea level rise has been identified as a long lasting consequence of anthropogenic climate change, as sea levels will continue to rise even if temperatures stabilize. Risk assessment and adaptation efforts depend on an assessment of future rates of mass loss from the ICE sheets. In addition to their impact on sea level rise, ICE sheets influence the earth's climate across different spatial and temporal scales due to changes in freshwater fluxes, orography, surface albedo and vegetation cover: ICE sheet evolution and iceberg discharge affect ocean freshwater fluxes, which can affect oceanic circulation. Changes in ICE sheet orography modify near surface temperatures by altering atmospheric circulation on both regional and global scale. Changes in surface albedo due to ICE sheet migration have played an important role in past interglacial-glacial transitions. Thus while ICE sheets are recognized as important players in the earth climate system quantification of feedbacks between ICE sheet and climate is still lacking. We propose continued development of the coupling effort of ICE sheet models to the two NASA climate models (geos-5 and giss modele) to gain insight into the effects of dynamic ICE sheets and associated feedbacks on the global climate system. We will use the existing two-way ICE sheet-atmosphere coupling developed in the first phase of this effort and combine IT with the latest insights into ICE sheet-ocean interactions. Specifically, we propose to improve the current state of the art parameterizations of melt rates beneath floating ICE shelf and generalize these parameterizations so that they can be used as a first order coupling between ICE sheet and global coarse ocean models, using insight from existing high resolution coupled ocean-ICE sheet model (mitgcm coupled to issm). Our science will explore the following questions: can we successfully hindcast the mass loss rates seen in grace solutions for greenland and wais? Are current rates of freshwater input currently influencing the north atlantic circulation? Do improved estimates of antarctic freshwater flux help explain the relatively stable antarctic sea ICE extent? Can we provide credible improved estimates of future mass loss?