Dear Andy > tidal_sea_surface_height_above_lowest_astronomical_tide > Units: m > "Sea surface height" is a time-varying quantity. "Height_above_X" means the > vertical distance above the named surface X. "Chart datum" describes a local > vertical reference from which depths displayed on a nautical chart are > measured and which differs from mean sea level. For example, chart datum > based on "lowest astronomical tide" or "mean lower low water". The tidal > component of sea surface height describes the predicted variability of the > sea surface due to astronomic forcing (chiefly lunar and solar cycles) and > shallow water resonance of tidal components; for example as generated based > on harmonic analysis, or resulting from the application of harmonic tidal > series as boundary conditions to a numerical tidal model.
The definition above needs revision (simplification in fact) to remove "chart datum". > non_tidal_elevation_of_sea_surface_height > Units: m > "Sea surface height" is a time-varying quantity. "Non_tidal_elevation" > describes the contribution to sea surface height variability made by > processes other than astronomic forcing of the ocean and shallow water > resonance of tidal components. These processes include storm surge (due to a > combination of meteorological forcing of the ocean and interaction between > the generated surge and tides), background ocean circulation, steric changes > in the water column and, at higher frequencies, effects of surface ocean > waves. The contribution made by these processes varies according to the > averaging time of the variable as described by the " bounds" and > "cell_methods" attributes. I suggest, "These processes include storm surge (due to a combination of meteorological forcing of the ocean and interaction between the generated surge and tides), effects of surface ocean waves, and seasonal and climatic variation in ocean density and circulation." Best wishes Jonathan _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
