Coastal Ocean Reanalysis
Gulf of America, Atlantic, and Caribbean, 1979-2022
Pacific, Hawaii, and Southern Alaska, 1979-2025
NOAA’s Coastal Ocean Reanalysis (CORA) helps create a more complete and consistent picture of historical water levels and waves along the U.S. coast. This nationwide, high-resolution dataset combines decades of observations from NOAA’s National Water Level Observation Network (NWLON) with modern numerical models to fill gaps between observations, and reconstruct historical coastal conditions.
By extending the value of NOAA’s tide gauge observations to areas where long-term measurements are limited or unavailable, CORA helps users better understand long-term sea level change and compare coastal flood risks today with those of the past. These data also support research, NOAA products, and new tools and applications for understanding and preparing for coastal hazards.
Curated Views
Flood frequency analysis uses historical records of when, where, and how often a place floods. Here, maximum water levels are modeled for every centerpoint with a continuous water level record. Elevation is modeled relative to Mean Sea Level (MSL), with areas in yellow representing water levels closer to MSL, and areas of red representing greater elevation. Each centerpoint has over 40 years of modeled data, allowing users to analyze flood frequency over time to support planning and mitigation efforts. Learn how to access, analyze, visualize, and transform data in GitHub
Gulf of America, Atlantic, Caribbean
- Click on the image to interact with the map on a new tab
- Explore CORA’s Gulf, Atlantic, and Caribbean datasets and
derived products by clicking the link
- Access, analyze, and visualize datasets with Python notebooks in
the CORA GitHub Repository
- Step by step instructions available through the User Guide:
User Guide PDF
CORA datasets combine the ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) models to represent data between National Water Level Observation Network (NWLON) observations. This modeling creates a mesh of irregular triangles every 200-500 meters at the coast. The center point, centroid, of each triangle is used to create native grid products. These datasets are ideal for time series analysis.
- Water Levels: Hourly & Max Water Level Elevation
- Waves: Hourly wave height, period, and direction
- Fort.14: Native grid model mesh
Gridded datasets and derived products are interpolated from the native grid to 500m squares to give data continuous spatial resolution. These datasets are ideal for geospatial applications and mapping.
- Water Levels: Hourly & Max Water Level Elevation
- Derived Datasets
Centroids from the native mesh that trace the coastline of each state. These are smaller datasets that focus solely on the coast.
Pacific, Hawaii, Southern Alaska
- Click on the image to interact with the map on a new tab.
- Explore CORA’s Pacific datasets and derived products by clicking
the link.
- Access, analyze, and visualize datasets with Python notebooks in
the CORA GitHub Repository
- Step by step instructions available through the User Guide:
User Guide
PDF
CORA datasets combine the ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) models to represent data between National Water Level Observation Network (NWLON) observations. This modeling creates a mesh of irregular triangles every 200-500 meters at the coast. The center point, centroid, of each triangle is used to create native grid products. These datasets are ideal for time series analysis.
- Water Levels: Hourly & Max Water Level Elevation
- Waves: Hourly wave height, period, and direction
- Coming soon!
- Coming soon!
A reanalysis combines historical observations with computer models to create a consistent picture of past conditions over time and across an area. Unlike a forecast, which looks ahead, a reanalysis looks back. It uses what we know about the past to provide a more complete picture of historical conditions, including in areas where long-term observations are limited or unavailable.
For CORA, decades of water level observations from NOAA tide gauges are combined with computer models and other data to reconstruct historical water levels and waves between and beyond tide gauge locations.
CORA helps fill historical data gaps between and beyond NOAA Tide gauge locations. NOAA tide gauges provide decades of valuable information about coastal water levels, but they can only measure conditions at specific locations. Coastal water levels and waves can vary between those locations, leaving gaps in our understanding of historical conditions along the coast.
CORA provides a consistent, high-resolution record that can help users understand coastal conditions in places where long-term observations are limited or unavailable.
CORA provides more than 45 years of information about historical coastal conditions across every 500-meters — roughly every quarter mile — along U.S. coasts. The dataset includes water levels and waves, along with atmospheric information such as wind speed, wind direction, and air pressure.
CORA provides this information in more places and at a finer scale than tide gauge observations alone, including locations between NOAA tide gauges and across a continuous grid. This gives users more information about the coastal environment, over a longer period of time, to support research, planning, and a wide range of coastal applications.
CORA combines NOAA’s long-term water level observations with computer models and atmospheric forcing to reconstruct historical coastal conditions. Water levels are modeled using the Advanced CIRCulation (ADCIRC) model, which is coupled with the Simulating WAves Nearshore (SWAN) model to simulate waves and their effects on coastal water levels. ERA5 provides the historical atmospheric forcing—including winds and air pressure—that helps drive the ADCIRC and SWAN models.
NOAA’s National Water Level Observation Network (NWLON) provides the long-term observations that are used to inform the models and improve the accuracy of the reanalysis. By bringing together observations, models, and atmospheric forcing, CORA creates a consistent, high-resolution reconstruction of historical water levels and waves across the coastal environment.
Partners
- NOAA’s Office for Coastal Management, Website: Contact Form
- NOAA’s Integrated Ocean Observing System, Email: noaa.ioos.webmaster@noaa.gov
- TetraTech — Cloud-data optimization
- University of North Carolina’s Renaissance Computing Institute
- University of Hawaii Sea Level Center
Extreme Water Levels
Analyze historical water levels between tide gauges to better understand extreme sea levels, storm surge, and compound flooding risk.
Machine Learning
Use decades of hourly CORA water levels to train, validate, and evaluate coastal prediction models, including models for storm surge and total water level forecasting.
Wave Climatology
Analyze historical wave height, direction, and energy to better understand coastal wave conditions and how they vary over time and space.
Sub-Seasonal Flood Prediction
Extend high tide flooding information beyond long-term tide gauge locations by using CORA's historical modeled water levels along the coastline.
Living Shoreline Decision Support
Incorporate historical wave conditions into tools that help evaluate, design, and prioritize living shoreline projects.
Flood Detection and Mapping
Use historical flood information from CORA to support the calibration and development of satellite-based flood detection and mapping products.
Compound Flood Modeling
Use CORA as a tidal boundary condition to calibrate hydrodynamic models in areas without tide gauges and better represent coastal influences on river and compound flooding.
Coastal Resilience Planning
Use historical flood frequency and wave information to identify areas exposed to recurring inundation and inform strategies such as wetland restoration, water retention, and nature-based solutions.
Coastal Engineering and Design
Apply historical wave and water level conditions to understand coastal exposure and support engineering, shoreline management, and resilience projects.
Enhanced Tidal Predictions
Potential for improving tide predictions at local water level gauges installed for as little as 30 days by combining astronomical tide predictions, seasonal cycle, and relative sea level changes.
References
- NOAA Technical Report NOS CO-OPS 108
- Frontiers in Marine Science: Assessment of water levels from 43 years of NOAA’s Coastal Ocean Reanalysis (CORA) for the East and Gulf Coasts
- Supplemental Validation for NOAA's CORA
- SEA LEVEL VARIATIONS OF THE UNITED STATES, 1854-2006
- Barotropic tides in the South Atlantic Bight
- Urgent Computing of Storm Surge for North Carolina's Coast
- A third-generation wave model for coastal regions: 1. Model description and validation
How to Cite
NOAA's Coastal Ocean Reanalysis (CORA) Dataset was accessed on DATE from https://registry.opendata.aws/noaa-nos-cora using notebooks from https://github.com/NOAA-CO-OPS/CORA-Coastal-Ocean-Reanalysis-CORA
CORA is a new and complex dataset. NOAA is committed to helping users understand, access, and apply it. Whether you're just getting started or looking for guidance on using CORA in your own research or applications, these resources can help.
Access CORA Datasets
Find the information you need to locate, understand, and download CORA datasets.
- Access, Analyze, and Visualize Datasets — CORA GitHub Repository
- Water Level & Wave Datasets — AWS Data Catalog
Learn About CORA
Build your understanding of CORA, the reanalysis process, and the data it provides.
- User Guide — Learn how CORA data are organized, accessed, analyzed, and visualized.
- Glossary — Find plain-language definitions for CORA terminology and key concepts.
- FAQs — Get answers to common questions about CORA and the reanalysis.
- Training Modules — Coming Soon! Explore interactive, plain-language training to build your understanding of CORA and its applications.
Get Help
Need help understanding or using CORA? NOAA can help.
- Request Technical Assistance — Submit a request for assistance with CORA data or applications by emailing tide.predictions@noaa.gov.