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.

Station Locations

• What are C-Man 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?

Sensors and Measurements

• Do NDBC's meteorological and oceanographic sensors measure data for the entire hour?
• What is Greenwich Mean Time (GMT)?
• 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?
• How 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, 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

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

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 real-time data?
• How can we hear NDBC observations over the phone?
• What are the alternate sources of real-time marine observations?

Accessing NDBC Data

• How can realtime data be retrieved from the NDBC web/FTP site?
• How can I receive observations via e-mail?
• 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 obtain historical, or archived, data?
• How can I get data certified for use in a court of law?
• Are there pre-done summaries of the data providing station climatology?

NDBC Programs and Information

• What is NDBC?
• What is NDBC's Mission?
• What is NDBC's History?
• What are some recent developments at NDBC?
• Who may I contact at NDBC for answers to my questions?
• Where can I find statistics about this web site?