Frequently Asked Questions

NDBC has compiled a list of the most frequently asked questions (FAQ) posed to NDBC personnel
by the many users of NDBC data. If the answer provided does not completely answer your question,
or if your question is not listed, please contact the Webmaster.

Stations

• Can you describe the moored buoys?
• How are the stations' ID numbers created?
• How can I compute the distance from a buoy to shore, an inlet, or another reference location?
• Where can I find out what stations are active and what data each station has available?

Sensors and Measurements

• Do NDBC's meteorological and oceanographic sensors measure data for the entire hour?
• Does NDBC measure ocean current velocities?
• Are the sensors used at NDBC sites periodically calibrated?
• What are the sensors reporting, sampling, and accuracy readings?
• At what heights are the sensors located on Moored Buoy and at C-MAN sites?
• Have the characteristics of our measurements changed through the period of record?

Wind Measurements

• What are "continuous wind" measurements?
• What averaging procedures are performed on the wind measurements?
• Does NDBC adjust C-MAN and buoy wind speed observations to a standard height?

Wave Measurements

• How are spectral wave data derived from buoy motion measurements?
• How are significant wave height, dominant period, average period, and wave steepness calculated?
• At what stations do we measure directional waves?
• How are estimates of wind-seas and swell made from NDBC wave data?
• How have the wave measurements changed through the period of record?

Observation Data from Other Providers

• What measurements from other data providers does NDBC process?
• How does NDBC receive and process observations from other data providers?
• Why send your observations to NDBC?
• How do you send observations to NDBC?
• What station information does NDBC need?
• Who do I contact at NDBC for more information?

Accessing NDBC Data

• What data are available for ingest from NDBC and how frequently are they updated?
• How can realtime data be retrieved from the NDBC web site?
• How can I receive observations via RSS?
• How can I receive observations via e-mail?
• How can we hear NDBC observations over the phone?
• How can I obtain historical, or archived, data?
• How can I get data certified for use in a court of law?
• What are the alternate sources of real-time marine observations?
• Are there pre-done summaries of the data providing station climatology?
• How can I link to the most recent BuoyCAM image for a station?

Data Formats

• How do you decode NDBC web data?
• How are the hourly data files formated and how can the files be used?
• How are the 5 day data files formated and how can the files be used?
• How can I decode the lowest one-minute pressure and peak one-minute winds?
• What is Greenwich Mean Time (GMT)?

Data Transmission and Quality Control

• How do the measured data get from the buoy or C-MAN site to the various users worldwide?
• Are the data quality controlled at any point in the process?
• How do you decode NDBC WMO message data?

DART®

• What is the difference between a tsunameter and DART®?
• What are the different operating modes of the tsunameters?
• How do I stay current with changes to the NDBC tsunameter network?
• What are the recent changes to DART messages?

Tropical Atmosphere Ocean (TAO)

• What types of plots are available in TAO data display?
• What climatologies are used in TAO data display?
• How does NDBC produce anomaly plots in TAO data display?
• What gridding methods are used in TAO data display?
• What wind direction convention is used in TAO data display and data delivery?

NDBC Programs and Information

• What is NDBC's Mission?
• Who may I contact at NDBC for answers to my questions?