National Aeronautics and Space Administration

Sea Level Rise Seminar
Speaker: Robin Bell (Columbia/LDEO)
Title: From Changing Ice to Working with Greenlandic Communities -- Greenland Rising

This is an on-line, virtual presentation only. Please consult with event host Craig Rye for connection details.

Abstract:
Studying the ice sheets as a system from the geologic underpinning to the coupling with the global oceans and atmosphere is essential to building robust projections of how these massive pieces of ice will change in the future. Changing sea level along the coastlines around the globe is the justification for almost every glaciologic proposal funded today. But how do we actually work to connect our work with communities? A team at Lamont have developed a program funded through NSF’s Navigating the New Arctic called Greenland Rising. The scientific framing is that across the Arctic, as glaciers and ice sheets retreat in the coming years, shallow environments and key marine habitats will change. Sea level will rise in some places and drop dramatically in others. These sea level changes throughout the Arctic will be the combined response of the solid Earth (uplift or subsidence) and gravity field to changes in past, present, and futures glaciers and ice sheets. Paired with distinct geologic settings, sea level change will be impacting infrastructure, fisheries, and navigation across Arctic coastal communities. A single number of projected sea level change from an ice sheet model in the coming decades is insufficient for communities in the New Arctic. Communities around the Arctic and around the globe will need to develop a framework for adapting to these changes that reflect their proximity to the changing ice and their local geologic setting. Due to the adjacent ice sheet, the signals of shallow water change in Greenland will be large -- the Greenland GPS Network (GNET) has documented uplift rates up to 23 mm/yr and subsidence rates of 5 mm/year in the southwest. Given the large changes, together with the ongoing economic, mining, natural resources and infrastructure development occurring in Greenland, it is critical to provide Greenlandic communities with a comprehensive, quantitative framework for understanding how shallow water environments will change in coming decades. The goal of the Greenland Rising project is to bring together a team focus for the first time on the natural, social, and built environment of Arctic communities proximal to a changing ice sheet. Building on strong partnerships with our Greenlandic colleagues we have been able to move forward through the pandemic.

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GISS Lunch Seminar
Speaker: Fangqun Yu (SUNY Albany)
Title: Use of machine learning and up-to-date algorithms to improve GISS ModelE aerosol number simulations: Implications for indirect aerosol forcing

This is an on-line, virtual presentation only. Please consult with event host Clara Orbe for connection details.

Abstract:
All cloud droplets formed in the atmosphere start with tiny particles that act as cloud condensation nuclei (CCN). These particles can alter cloud properties and precipitation, and their effects on cloud radiative forcing remain the largest source of uncertainty in climate prediction. The GISS global climate models have been making and will continue to make important contributions to the Coupled Model Intercomparison Project (CMIP) and IPCC climate change assessments. The recent historical simulations of the GISS ModelE2.1 for CMIP6 are based on either a mass-based One-Moment Aerosol (OMA) or a quadrature-method-of-moments-based MATRIX aerosol module. The aerosol radiative forcing values and trends over the past decades differ for MATRIX and OMA, even though the host model and emissions were the same. One critical step toward better modeling aerosols' effect on clouds is to have a robust representation of major aerosol processes that are important for determining particle number concentrations (PNC).

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