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Item Identification
Physical Location
Data Set Info
Support Roles
Spatial Info
Access Info
Distribution Info
Tech Environment
Data Quality
Catalog Details


Short Citation
Office for Coastal Management, 2024: US Wave by Month,
Full Citation Examples


These data depict a wave energy resource characterization for the US Exclusive Economic Zone. This climatology is based on a multi-resolution 32 year hindcast that used the WaveWatchIII and Simulating WAve Nearshore (SWAN) wave models. A collection of five variables are reported at the annual and monthly intervals. Statistics for each variable are provided as point and hexagon features.

Controlled Theme Keywords


Child Items

No Child Items for this record.

Contact Information

Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
(843) 740-1202


Geographic Area 1

-179.9° W, 179.9° E, 61.5° N, 15° S

Time Frame 1

publication date

Item Identification

Title: US Wave by Month
Status: Completed
Publication Date: 2023-11-23

These data depict a wave energy resource characterization for the US Exclusive Economic Zone. This climatology is based on a multi-resolution 32 year hindcast that used the WaveWatchIII and Simulating WAve Nearshore (SWAN) wave models. A collection of five variables are reported at the annual and monthly intervals. Statistics for each variable are provided as point and hexagon features.


To support ocean planning activities pursuant to the Executive Order Regarding the Ocean Policy to Advance the Economic, Security, and Environmental Interests of the United States, the Energy Policy Act, the National Environmental Policy Act, the Rivers and Harbors Act, and the Coastal Zone Management Act.

Supplemental Information:

Bureau Code: 006:48, Program Code: 006:055


Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
ISO 19115 Topic Category
ISO 19115 Topic Category
None coastal
None planning
None renewable energy

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
None Exclusive Economic Zone
None Outer Continental Shelf
None Territorial Sea

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Data Presentation Form: Map (digital)
Entity Attribute Overview:

waveDirection, waveAbsolutePeriod, significantWaveHeight, wavePeakPeriod, maximumEnergyDirection

Distribution Liability:

Data Set Credit: DOE National Renewable Energy Laboratory, DOE Pacific Northwest National Laboratory

Support Roles

Point of Contact

CC ID: 1186128
Date Effective From: 2018-06
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Publication Date

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1186140
W° Bound: -179.9
E° Bound: 179.9
N° Bound: 61.5
S° Bound: 15

Extent Group 1 / Time Frame 1

CC ID: 1186139
Time Frame Type: Discrete
Start: 2022-10-14

publication date

Spatial Information

Spatial Representation

Representations Used

Grid: No
Vector: Yes
Text / Table: No
Stereo Model: No
Video: No

Vector Representation 1

CC ID: 1186134
Complex Object Present?: No
Composite Object Present?: No
Curve Object Present?: Yes
Point Object Present?: Yes
Solid Object Present?: No
Surface Object Present?: No

Reference Systems

Reference System 1

CC ID: 1186135

Coordinate Reference System

CRS Type: Geographic 2D
EPSG Code: EPSG:4269
EPSG Name: NAD83
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Use Constraints:

For coastal and ocean planning

Distribution Information

Distribution 1

CC ID: 1186129
Download URL:
Description: Data Registry

Distribution 2

CC ID: 1282331
Download URL:

Distribution 3

CC ID: 1186130
Download URL:

Distribution 4

CC ID: 1199437
Download URL:

Distribution 5

CC ID: 1199436
Download URL:

Technical Environment


Microsoft Windows, ArcGIS Pro, Azure SQL

Data Quality



Horizontal Positional Accuracy:

Compiled to meet 10 meters horizontal accuracy at 95% confidence level

Completeness Report:


Conceptual Consistency:

These data are logically consistent



National Renewable Energy Laboratory (2020). High Resolution Ocean Surface Wave Hindcast (US Wave) Data. Retrieved from

CC ID: 1186136
Contact Role Type: Originator
Contact Type: Organization
Contact Name: National Renewable Energy Laboratory
Extent Type: Discrete
Extent Start Date/Time: 2022
Citation URL:
Source Contribution:

Source data by URL

Process Steps

Process Step 1

CC ID: 1186137

The hindcast data processing consisted of the following main steps:

1. Read, filter, and calculate individual years annual/monthly statistics from annual data files and save

a. Using the NREL Developer API the hindcast data output was read directly from the AWS repository.

b. Each regional annual file was read individually, filtering the data from a 3-hour time step to a daily time step (every 8th time step). This was required for efficient processing speed and reasonable storage needs.

c. Of the ten wave data variables available only 5 were used in this data processing:

i. Mean Wave Direction - Direction Normal to the wave crests (compass direction, where wave is coming from)

ii. Significant Wave Height - Wave height based on the zeroth spectral moment (i.e., H_m0)

iii. Mean Absolute Period - Resolved Spectral Moment (m_0/m_1)

iv. Peak Period - The period associated with the maximum value of the wave energy spectrum

v. Maximum Energy Direction - The direction from which the most wave energy is travelling (compass direction, where wave is coming from)

d. While reading the data bad (missing) values were removed. For the West Coast and Hawaii regions these values were represented with either -9 or -999, in the Atlantic region these were represented by nan.

e. All the daily time step values were collected and then averaged for the whole year and for each month of the year. This averaged data was then written to a local CSV file with the hindcast node ID, decimal degree coordinates, and 5 wave variable statistics.

i. The two wave direction variables were handled slightly differently (see below).

f. For the two direction variables:

i. Averaging the direction (in degrees) without vector data would not prove accurate averages. Instead, the directions were binned into 16 direction bins. Each bin covered 22.5 degrees and was represented by the degree value in the middle of that range, for example, the bin covering 78.75-101.25 was written as 90, and the range of +/-11.25 around 0 (north) was written as 0. This binning was done to support identifying the mode later when annual/monthly statistics were calculated.

ii. Instead of calculating and saving the annual and monthly average, the number of occurrences for each directional bin throughout that year was tallied for the annual and monthly timescales and was saved as a CSV.

2. Calculate annual and monthly statistics for the full 32-year period

a. Once all annual and monthly files were prepared, the statistics for each wave variable were prepared to cover the full 32-year period at an annual and monthly level.

b. For the period and height variables:

i. The mean value for each of the individual years was averaged together and saved for each hindcast data point in a CSV for the annual and monthly means.

c. For the direction variables:

i. Using the frequency data by directional bin, the annual and monthly values for all 32 years were totaled for each bin. The bin with the largest frequency over the 32 years (mode) was selected and the direction for that bin was saved in a CSV for the annual and monthly means.

ii. At the same time, another set of CSV files were saved that included the totaled frequencies for each bin both on an annual and monthly level covering the full 32-year period. These statistics were used later to help generate the gridded summary products.

Process Date/Time: 2022-10-14 00:00:00

Process Step 2

CC ID: 1186141

1. Hind Cast Points with annual statistics

a. From one of the annual CSV files, a point feature class was created using the latitude and longitude of each hindcast data point. The hindcast record id was also incorporated as a unique point id.

b. The annual statistic for each of the five variables was then incorporated as an attribute for each point.

c. Any points where all of the five statistics where NULL (mainly just points near the shoreline, that were also NULL in the hindcast data) were removed.

2. Tables of Monthly statistics for each variable

a. Each of the monthly statistic CSV files were converted to a geodatabase table.

b. The table consisted of the Point ID (that matches the point in the annual points feature class) and then twelve fields with the statistics for each month.

c. Any table records where the statistics were all NULL, were removed from the table (these were the same records that were removed from the annual point dataset)

3. Summary Hexagon Grid Creation

a. A hexagon grid was created using 3 resolutions (1 km2, 10 km2, and 100 km2) using the ArcGIS Pro - Generate Tessellation geoprocessing tool, with the following settings:

i. Spatial Reference - EPSG:3857 WGS84 Web Mercator (Auxiliary Sphere) - using this ensures that the hexagons will look correct in a map service and works for a projected coordinate system for all regions.

ii. Shape Type - Hexagon

iii. Extent - same as the hindcast point extent for that region

iv. Cell size - 1 km2, 10 km2, or 100 km2

b. An attribute field was added to each of the hexagon grids to store annual wave direction mode, mean absolute period, and mean significant wave height summary statistics.

c. Wave statistics were then summarized based on all the hindcast data points that fell within each hindcast hexagon cell (for each resolution).

i. For the mean absolute period and mean significant wave height:

1. Used the ArcGIS Pro Summarize Within geoprocessing tool to calculate the mean for each hexagon cell and each variable:

a. Input - hexagon grid feature class

b. Summary Features - annual hind cast point feature class

c. Kept all input polygon features

d. Statistics - mean for both period and height variables

2. Joined this output to the original hexagon layer and populated both variable attribute fields with these results

ii. For the wave direction mode:

1. Created a temporary point feature class from the annual wave direction bin frequency data (count of occurrence in each bin over the whole 32-years).

2. Used the ArcGIS Pro Summarize Within geoprocessing tool to calculate the sum for each cell:

a. Input - hexagon grid feature class

b. Summary Features - temporary points of direction bin frequency

c. Kept all input polygon features

d. Statistics - sum for each of the 16 direction bin frequency fields

3. For each hexagon grid cell, the direction bin that had the largest frequency (sum of all point frequencies within that cell) was identified as the mode, and the direction mode was set to be that bin's mid-point direction in degrees.

4. Joined this output to the main hexagon layer and populated Wave Direction Annual Mode attribute field with these results.

Process Date/Time: 2022-10-14 00:00:00

Process Step 3

CC ID: 1282332

Added data for the Alaska region

Process Date/Time: 2023-11-22 00:00:00

Catalog Details

Catalog Item ID: 67978
GUID: gov.noaa.nmfs.inport:67978
Metadata Record Created By: Daniel Martin
Metadata Record Created: 2022-10-03 12:02+0000
Metadata Record Last Modified By: Jesse Brass
Metadata Record Last Modified: 2024-01-22 20:07+0000
Metadata Record Published: 2022-12-18
Owner Org: OCM
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2019-04-25
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2020-04-25