Lowest Astronomical Tide (LAT) is defined as the lowest tide level which can be predicted to occur under average meteorological conditions and under any combination of astronomical conditions. The Lowest Astronomical Tide is the height above the lowest tidal water level, which can be used for a level alone on the basis of the contained locally dominant . Highest Astronomical Tide(HAT) and Lowest Astronomical Tide(LAT) are hypothetical . Meteorological effects (storm surge) are not included in these limits. In the United Kingdom, this level is normally approximately the level of Lowest Astronomical Tide. Chart Datum is shown on charts as the zero metre contour. . knowledge of the ellipsoidal heights of lowest astronomical tide (LAT). . and the pursued approach exist if average monthly variations in MSL are included. This paper highlights key aspects of the article 'Lowest Astronomical Tide in the North Sea derived from a shallow water model, and an assessment of its . The HAT and LAT are the highest and lowest astronomical tidal levels during the is used for the harmonic analysis, and 145 tidal constituents are included. of CD, i.e. the Lowest Astronomical Tide (LAT) as adopted by . LAT is defined as the lowest tide level to occur under average . should be included separately. of the ellipsoidal heights of Lowest Astronomical Tide (LAT). variation in water level), which is also included in the reconstruction of the astronomical tide.