NOAA Water Levels for Coastal, Estuaries and Great Lakes regions

For over 200 years, NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) and its predecessors have been managing a comprehensive system for observing, communicating, and assessing water levels nationwide, including on the Great Lakes, and in certain U.S. territories. The standard data collected from our water level stations are reported in 6-minute intervals, and support the National Water Level Observation Network (NWLON), short-term Vertical Datum (VDatum) Projects, the National Tsunami Warning System, the Physical Oceanographic Real-Time System, or PORTS Program, and other partnerships. These data are quality controlled and used to support safe and efficient maritime commerce, sound coastal management, recreation, and studies in sea level and climate changes. The secondary datasets derived from these observations are highs and lows (except for Great Lakes), hourly heights, daily means (Great Lakes only), and monthly means, from which all other CO-OPS datasets are derived for datums, tidal predictions, and sea level applications. Hourly heights in particular are utilized to calculate historic high tide flooding statistics, and to compute monthly mean sea level values, which are incorporated into tidal datums for nautical charting and harmonic constituents for generating tidal predictions. Note: both products of high tide flooding statistics and tidal predictions are calculated on the fly and are not stored, nor considered as data.

The mission of NOAA's National Ocean Service's (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) is to provide the national infrastructure, and the scientific and technical expertise to monitor, assess, and distribute tide, water level, tidal current, meteorological and other coastal oceanographic products and services necessary to support NOAA's mission.

Raw data have not been subjected to the National Ocean Service's (NOS) quality control or quality assurance procedures and do not meet the criteria and standards of official NOS data. Users are cautioned to always review these data closely to ensure that they are appropriate for their intended use. Verified data have been subjected to the NOS quality control or quality assurance procedures, and meet criteria and standards. Processing and verifying CO-OPS water level data is a two-person process. Each month, an analyst reviews a station’s data (filling data gaps, removing erroneous spikes, etc.) for the previous calendar month’s data. In most cases, the raw 6-minute data points end up becoming the verified 6-minute data, minus spikes and gaps. Once the re-viewer is done, the second person confirms the work of the reviewer, and marks the data in the database as “verified.” At the moment of being marked as such, that month’s verified 6-minute data and other products (high-lows, hourly heights, daily and monthly means) become available on the CO-OPS web site and web services. Each month, the water level stations are processed/verified in random order, to prevent the same stations or geo-graphical areas from always being first or last.

Sensors used today are one of four types: acoustic, microwave water level (MWWL), shaft angle encoder (Great Lakes), and pressure sensor (bubbler). The type of sensor used depends on the station’s environment. The lack of infrastructure may prevent the use of the desired sensor type at that location.

Latest detailed information on sensors and accuracy can be found at: https://tidesandcurrents.noaa.gov/publications/CO-OPS_Measurement_Spec.pdf

Raw data have not been subjected to the National Ocean Service's quality control or quality assurance procedures and do not meet the criteria and standards of official National Ocean Service data. They are released for limited public use as preliminary data to be used only with appropriate caution.

None

Preliminary (raw) data have not been subjected to the National Ocean Service's quality control or quality assurance procedures and do not meet the criteria and standards of official National Ocean Service data. They are released for limited public use as preliminary data to be used only with appropriate caution. Historical data are only good for observations and may not reflect present day conditions. These data are only representative of the geographic location of the observation.

Raw data have not been subjected to the National Ocean Service's quality control or quality assurance procedures and do not meet the criteria and standards of official National Ocean Service data. They are released for limited public use as preliminary data to be used only with appropriate caution.

Raw data have not been subjected to the National Ocean Service's quality control or quality assurance procedures and do not meet the criteria and standards of official National Ocean Service data. They are released for limited public use as preliminary data to be used only with appropriate caution.

Data are recorded and transmitted; then go through a quality control procedure and are loaded into a database.