NOAA's Coastal Ocean ReAnalysis (CORA): Making Maps without Gaps Through Community-Based Modeling

NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) maintains and operates NOAA's National Water Level Observation Network (NWLON), which provides real-time and historic water level observations at over 200 locations across U.S. coastlines. While very useful, NWLON-based information may only be representative of the conditions in the immediate vicinity of each water level station, creating gaps in data and product coverage between stations that can exceed 200 miles. CO-OPS is leading a community-based numerical modeling reanalysis to bridge disparities in service and more equitably serve coastal communities. NOAA’s Coastal Ocean ReAnalysis (CORA) is the result of a collaboration across the Federal government, academic institutions and private industry and will become an important benchmark for coastal water level analysis and derived flood products. By assimilating long-term water level observations (1979-2022, thus far) with hydrodynamic modeling, CORA supports efforts to consistently fill gaps in the coastal-ocean observation record and minimize uncertainties in coastal water level change. Numerical solutions on CORA’s unstructured meshes are interpolated onto a continuous geospatial grid of the US East and Gulf coasts with 500m resolution to simplify product development. Published skill assessments for the Gulf, Atlantic, and Caribbean show that CORA performed well compared to NWLON observations. New ways of performing data assimilation and model optimization using CORA for coastal water prediction on sub-seasonal to seasonal timeframes are currently being tested through nested and global ensemble modeling approaches to improve model performance and address computational efficiencies.