Tides
Great Lakes
Water Level Predictions
Bench Mark Data Sheets
Datums
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products
Tides & Currents ProductsNOAA's Tides and Currents website, developed and supported by the Center for Operational Oceanographic Products and Services (CO-OPS), provides the following products. A definition of each term and a description of each product are provided. Links are on the left side of the page. For more information, see the contact information at the bottom of the page.
Great Lakes Water Level - The height of the level of water relative to a datum (see below). The Great Lakes are not as affected by gravitational interactions among the sun, moon, and earth as many other areas of the country are, so we cannot measure a predictable tide in these locations. Changes in water level are usually due to weather events. Users can retrieve data from active or historic stations.
Predictions - A calculation of what the water level or current direction will be based on harmonic constituents (see below). This site offers six-minute and hourly tide/water level predictions "on-the-fly" for all stations with harmonic constituents. It also offers high/low data for all stations in NOAA's published tide and current table. Meteorological Observations - Many water level stations are equipped with meteorological sensors to collect meteorological observations in conjuction with water level data. The following observations may be retrieved from this website: wind speed and directions, air temperature, water temperature, barometric pressure, relative humidity and conductivity/salinity. Conductivity - Conductivity is provided at several stations.
Datums - For marine applications, a base elevation used as a reference from which to reckon heights or depths. It is called a tidal datum when defined in terms of a certain phase of the tide. Tidal datums are local datums and should not be extended into areas that have differing hydrographic characteristics without substantiating measurements. In order that they may be recovered when needed, such datums are referenced to fixed points known as benchmarks. The "Present Epoch" is from 1983-2001 and includes the latest datums available. The "Superseded Epoch" is from 1960-1978 and has been replaced by the "Present" datums, or was not replaced due to insufficient data.
Operational Forecast Systems - Nowcasts and forecast guidance are scientific predictions about the present and future states, respectively, of water levels (and possibly currents and other relevant oceanographic variables, such as salinity and temperature) in a coastal area made by a numerical model. These predictions rely on either observed or forecast data. A nowcast incorporates recent (and often near real-time) observed meteorological, oceanographic, and/or river flow rate data. A nowcast covers the period of time from the recent past (e.g., the past few days) to the present, and it makes predictions for locations where observational data are not available. The present is the time at which the nowcast is made, and at which the most recent observations are from a few minutes to an hour old. A forecast guidance incorporates meteorological, oceanographic, and/or river flow rate forecasts and makes predictions for locations where observational data will not be available. A forecast guidance is usually initialized by the results of a nowcast. Tides Online - Tides Online was developed to show a list of water level stations that are being affected by a storm. It has since become a quick and easy way to view data for any station of interest. Great Lakes Online - A sister page to Tides Online focused specifically on the Great Lakes region. Sea Level Trends - The rate of mean sea level rise or fall has been determined for 117 long-term water level stations. Monthly mean sea level data were used to obtain the linear trend, the average seasonal cycle, and the interannual variations. The linear trend at a coastal location is primarily a combination of the global sea-level rise and any local vertical land movement. The seasonal cycle and interannual variations are caused by fluctuations in coastal ocean temperatures, salinities, winds, atmospheric pressures, and currents. The interannual variations for many Pacific stations are closely related to the El Nino/Southern Oscillation. Assuming no change in trend, the time series of interannual variations are extended up to the latest month, and maps are created to show the regional extent of anomalously high or low water levels. Astronomical - Of all the constituents, the moon has the greatest effect on tides. This page provides information on the various phases of the moon. nowCOAST - NowCOAST is a web mapping portal providing spatially referenced links to thousands of real-time coastal observations and NOAA forecasts of interest to the marine community. Harmful Algal Blooms - The Harmful Algal Bloom Forecast System (HAB-FS) provides advance notice of harmful algal blooms, including possible impacts to the public, location, extent, and the potential for HAB development or movement. Contact Information |