Hello Guenther, There is a lot here and so far I have just had time to look at your first proposed Standard Name. What I don't understand is the time context of your data. There are two high tides per day (or even four in places like the Solent), each of which has a different high water level and of course these differ from day to day due to spring-neap cycles. To what period of time does tidal_high_water_above_sea_level refer?
Maybe if you explained a little about the type of data you are trying to encode into CF I might understand a little better. Cheers, Roy. Please note that I now work part-time from Tuesday to Thursday. E-mail response on other days is possible but not guaranteed! From: "Lang, Günther" [mailto:guenther.l...@baw.de] Sent: 04 June 2014 13:51 To: cf-metadata@cgd.ucar.edu Subject: [CF-metadata] new standard names : tidal quantities tidal_high_water, ... Preface It is suggested to introduce new standard names for several tidal quantities like (tidal) high_water, low_water etc. These are geophysical concepts and it would be not adequate to describe them with cell_methods and/or time bounds. --- 1.) tidal_high_water_level_above_sea_level [ m ] The maximum height reached by a rising tide. The high water is due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 2.) tidal_low_water_level_above_sea_level [ m ] The minimum height reached by a falling tide. The low water is due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 3.) tidal_range [ m ] Arithmetic mean between tidal rise and tidal fall. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 4.) half_tide_level_above_sea_level [ m ] Water level at half tidal range. The level midway between high water and mean low water for a tide. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 5.) mean_tide_water_level_above_sea_level [ m ] The mean surface elevation as determined by averaging the heights of the water at equal intervals of time for a tidal period, which is the interval between two successive low waters. Differs from half tide level due to tidal asymmetry. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 6.) mean_tidal_rise_water_level_above_sea_level [ m ] (opt) mean_flood_water_level_above_sea_level [ m] The mean surface elevation as determined by averaging the heights of the water at equal intervals of time for the period of tidal rise, which is the interval from low water to high water. Differs from mean water level during tidal fall due to tidal asymmetry. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 7.) mean_tidal_fall_water_level_above_sea_level [ m ] (opt) mean_ebb_water_level_above_sea_level [ m] The mean surface elevation as determined by averaging the heights of the water at equal intervals of time for the period of tidal fall, which is the interval from high water to low water. Differs from mean water level during tidal rise due to tidal asymmetry. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Sea_level means mean sea level, which is close to the geoid in sea areas. --- 8.) duration_of_tidal_rise [ s ] Duration of rise is the interval from low water to high water. In combination with duration_of_tidal_fall they cover, on an average, a period of 12.42 hours for a semidiurnal tide or a period of 24.84 hours for a diurnal tide. In a normal semidiurnal tide, duration of rise and duration of fall each will be approximately equal to 6.21 hours, but in shallow waters and in rivers there is a tendency for a decrease in duration of rise and a corresponding increase in duration of fall. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 9.) duration_of_tidal_fall [ s ] Duration of fall is the interval from high water to low water. In combination with duration_of_tidal_rise they cover, on an average, a period of 12.42 hours for a semidiurnal tide or a period of 24.84 hours for a diurnal tide. In a normal semidiurnal tide, duration of rise and duration of fall each will be approximately equal to 6.21 hours, but in shallow waters and in rivers there is a tendency for a decrease in duration of rise and a corresponding increase in duration of fall. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 10.) duration_of_tide [ s ] (opt) tidal_period [ s ] Interval between two successive low waters. Sum of duration_of_tidal_rise and duration_of_tidal_fall. On an average, a period of 12.42 hours for a semidiurnal tide or a period of 24.84 hours for a diurnal tide. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 11.) time_of_occurrence_of_tidal_high_water [ s ] Time when high water occurs. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 12.) time_of_occurrence_of_tidal_low_water [ s ] Time when low water occurs. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 13.) tidal_difference_for_time_of_occurrence_of_tidal_high_water [ s ] Difference in time of a high water at a subordinate station and at a reference station. The difference, when applied according to sign to the time at the reference station, gives the corresponding time for the subordinate station. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 14.) tidal_difference_for_time_of_occurrence_of_tidal_low_water [ s ] Difference in time of a low water at a subordinate station and at a reference station. The difference, when applied according to sign to the time at the reference station, gives the corresponding time for the subordinate station. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 15.) tidal_rise [ m ] Vertical difference between the water level at low water and the water level at the subsequent high water. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 16.) tidal_fall [ m ] Vertical difference between the water level at high water and the water level at the subsequent low water. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 17.) duration_of_wetting_due_to_tidal_flooding [ s ] Duration for which a location is covered with water due to tidal flooding. Within the intertidal zone, flooding may last from 0.00 (always dry) up to, on an average, 12.42 hours (always wet) for a semidiurnal tide. Or up to, on an average, 24.84 hours for a diurnal tide. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. --- 18.) duration_of_drying_due_to_tidal_ebbing [ s ] Duration for which a location is not covered with water due to tidal ebbing. Within the intertidal zone, ebbing may last from 0.00 (always wet) up to, on an average, 12.42 hours (always dry) for a semidiurnal tide. Or up to, on an average, 24.84 hours for a diurnal tide. Due to the periodic tidal forces and the effects of meteorological, hydrologic, and/or oceanographic conditions. Günther Lang Bundesanstalt für Wasserbau - Dienststelle Hamburg Referat Ästuarsysteme II Wedeler Landstraße 157 22559 Hamburg Telefon +49 (0) 40 81908 360 E-Mail guenther.l...@baw.de<mailto:guenther.l...@baw.de> ________________________________ This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.
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