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Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities, including economic development, security and defense, scientific research, and environmental protection.
A radiosonde is a battery-powered telemetry instrument carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Modern radiosondes measure or calculate the following variables: altitude, pressure, temperature, relative humidity, wind, cosmic ray readings at high altitude and geographical position (latitude/longitude). Radiosondes measuring ozone concentration are known as ozonesondes.
A nautical chart or hydrographic chart is a graphic representation of a sea region or water body and adjacent coasts or banks. Depending on the scale of the chart, it may show depths of water (bathymetry) and heights of land (topography), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, critical data such as Local Notices to Mariners are added to the on-demand chart files so that these charts are up to date at the time of printing.
The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.
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The lunitidal interval measures the time lag from lunar culmination to the next high tide at a given location. It is also called the high water interval (HWI). Sometimes a term is not used for the time lag, but instead the terms age or establishment of the tide are used for the entry that is in tide tables.
Wynyard (/ˈwɪnjɚd/) wi-nyuhd) is a rural town located on the North West coast of Tasmania, Australia. Wynyard is situated 17 kilometres (11 mi) west of Burnie. As of the 2021 census, Wynyard has an estimated population of 6,296 The town is a regional hub servicing the surrounding rural areas, the adjacent Burnie Wynyard Airport provides commercial flights to Melbourne and other districts. The main council offices for the Waratah-Wynyard local government area are located in Wynyard.
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Head of tide, tidal limit or tidehead is the farthest point upstream where a river is affected by tidal fluctuations, or where the fluctuations are less than a certain amount. The river section influenced by tides and marine forces but without salinity is a tidal river, while downstream areas are brackish and termed estuaries.
Arthur Thomas Doodson was a British oceanographer.
In geodesy, surveying, hydrography and navigation, vertical datum or altimetric datum, is a reference coordinate surface used for vertical positions, such as the elevations of Earth-bound features and altitudes of satellite orbits and in aviation. In planetary science, vertical datums are also known as zero-elevation surface or zero-level reference.
A coastal skipper is a yachtsman or woman who has the ability to skipper a yacht in coastal waters by day or night. There is a shore-based course which provides the background knowledge required, a practical course which teaches the skills and techniques required, and a Certificate of Competence.
The Tuvalu Meteorological Service (TMS) is the principal meteorological observatory of Tuvalu and is responsible for providing weather services to the islands of Tuvalu. A meteorological office was established on Funafuti at the time the islands of Tuvalu were administered as parts of the Gilbert and Ellice Islands colony of the United Kingdom. The meteorological office is now an agency of the government of Tuvalu.
The National Operations Centre Tidal Unit is a group of experts responsible for providing tidal tables and tidal predictions to the Australian Hydrographic Service. Their tidal predictions are also published on the Australian Bureau of Meteorology website.
References
- ↑ Admiralty Tide Tables – ATT. Taunton, UK: UKHO – United Kingdom Hydrographic Office. 2010. p. vi.
- ↑ "Definitions of tidal terms". LINZ – Land Information New Zealand. Retrieved 1 October 2013.
- ↑ "An explanation of tidal information". Cambridge school of navigation. Archived from the original on 4 October 2013. Retrieved 1 October 2013.
- ↑ "About us – Australian National Tidal Center" (PDF). Bureau of Meteorology. Archived from the original (PDF) on 16 October 2013. Retrieved 1 October 2013.
- ↑ "Notes and definitions". Tides. Maritime Safety Queensland. Retrieved 1 October 2013.
- ↑ "Tides". Terrestrial Navigation. www.thenauticalsite.com. Archived from the original on 8 August 2013. Retrieved 1 October 2013.
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