Arthur Thomas Doodson (31 March 1890 – 10 January 1968) was a British oceanographer. Early life and education Arthur Thomas Doodson was born in 1890 at Boothstown, Salford, the son of cotton-mill manager Thomas Doodson and Eleanor Pendlebury of Radcliffe, Lancashire. He was educated at Rochdale secondary school and in 1908 entered the University of Liverpool, graduating in both chemistry (1911) and mathematics (1912). He was profoundly deaf and found it difficult to get a job but started with Ferranti in Manchester as a meter tester. In 1914, he obtained his M.Sc. degree of Liverpool University and in 1916 he was appointed to a post in statistics at University College, London, under Karl Pearson but soon had to work on the calculation of shell trajectories. He obtained the D.Sc. in 1919. Career In 1919, he moved back to Liverpool to work on tidal analysis. In 1921, Doodson published a major work on tidal analysis. This was the first development of the tide generating potential to be carried out in harmonic form: Doodson distinguished 388 tidal frequencies. Doodson's analysis of 1921 was based on the then-latest lunar theory of E W Brown. Doodson devised a practical system for specifying the different harmonic components of the tide-generating potential,the Doodson Numbers. In 1929, he became the Associate Director of Liverpool Observatory and Tidal Institute under the direction of Joseph Proudman. He then spent much of his life developing the analysis of tidal motions mainly in the oceans, but also in lakes, and was the first to devise methods for shallow water as in estuaries. Tide height and current tables are of great importance to navigators, but the detailed motions are complex. The thorough analysis at which he excelled became the international standard for the study of tides and the production of tables through the method of determination of Harmonic Elements by Least-Squares Fitting to data observed at each place of interest. That is, by proper association of the astronomical phases, observations made at one time can enable predictions decades away with different astronomical phases. WWII Doodson used and became involved in the design of tide-predicting machines, of which a widely used example was the "Doodson-Légé TPM". Among other works, Doodson was co-author, with H.D. Warburg of the 1941 "Admiralty Manual of Tides". As the Allies prepared the invasion of Nazi-occupied France, they wanted to land at first light when it was low tide,