Dynamic Model Downscaling of Climate Change and Its Impacts on Marine Environmental Conditions off North Carolina

Keywords

Climate change may lead to two types of sea level rise: 1) the rise due to a warming climate, which results in ocean thermal expansion and ice melt, and 2) the rise due to ocean dynamic adjustment of sea surface height (SSH) in response to a slowdown of the Atlantic meridional overturning circulation (AMOC). The AMOC resembles a north-south oceanic conveyor belt, circulating water at the surface and ocean bottom in the Atlantic. The Gulf Stream (GS) is the northward surface flow of the AMOC. Its high flow rate and volume cause the steep dynamic SSH gradient across the continental shelf of the United States’ east coast.

The slowdown of the AMOC and GS projected by climate models used by the Intergovernmental Panel on Climate Change (IPCC) would dramatically decrease the SSH gradient, leading to rapid sea level rise at the coast. This makes the U. S. east coast including North Carolina’s coast among the most vulnerable regions to future changes in sea level and ocean circulation, especially when considering its population density and the potential socioeconomic consequences of such changes. Regional changes in sea level and coastal circulation therefore have significant impacts on interannual variability of water mass compositions, pollutant exchange, and marine environmental dynamics including fisheries productivity and harmful algal blooms off NC. Because climate models, typically having a spatial resolution of 100-200 km, are incapable of resolving these regional-scale ocean processes, this project led by NC State Marine Earth and Environmental Sciences Professor Roy He will investigate a suite of high resolution simulations of future climate change impacts at the NC coastal region by dynamically downscaling global climate scenarios using a newly developed regional ocean model and multi-scale nesting capability.

The project goal is to provide NC coastal communities and resource managers with site-specific information on the potential impacts of sea level rise and marine environment on NC coastal communities and habitats and their associated ecosystem services. Dr. He and his research team will develop an integrated data flow and methodology for processing, summarizing, viewing, and delivering the resulting climate datasets to a wide range of potential users, so the long-term time series of internally consistent ocean state data produced by his research simulations can be used in a broad spectrum of climate-related research. Kenan Institute support for this project leverages a $5M, 4-year (2016-2020) NSF Award to study physical processes driving exchange between the shelf and deep ocean at Cape Hatteras.