Atlas of Ocean Tidal Charts and Maps. Part 1. The Semidiurnal Principal Lunar Tide M2
NAVAL SURFACE WEAPONS CENTER DAHLGREN VA
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In this paper the author presents the NSWC ocean tide model of the semidiurnal principal lunar M2 tide in an atlas of ocean tidal charts and maps. The model is the computer result of a unique combination of mathematical and empirical techniques, which was introduced, extensively tested, and evaluated by Schwiderski 1978a, 1980a, b, 1983e. The computer M2 amplitudes and phases are tabulated along with all specifically labeled empirical input data on a 1 by 1 deg grid system in 42 by 71 deg overlapping charts covering the whole oceanic globe. Corresponding global and arctic corange and cotidal maps are included to provide a quick overview of the major tidal phenomena. Significant qualitative and quantitative features are explained and discussed for proper application. In particular, the charted harmonic constants may be used to compute instantaneous M2 ocean tides with an accuracy of better than 5 cm any time and anywhere in the open oceans. Limitations of this accuracy in coastal waters and border seas are mentioned. The following four sections of this paper deal with brief reviews, detailed evaluations, and simple improvements of general and special applications of the NSWC ocean tide model. In spite of the numerous and diverse applications with potential possibilities of erroneous interpretations, the results are gratifying without exceptions. For instance, it is concluded that the computed low-degree spherical harmonic coefficients of the M2 ocean tide model agree with recent empirical satellite solutions as closely as one could wish for within the elaborated nonmodel error bounds. Detailed computations of all significant tidal energy terms produced the following noteworthy results The rate of supplied tidal energy of 2.50Z10 Watt matches Cartwrights 1977 estimate of 3.5Z10 Watt. The rate of energy loss by bottom friction and displacement over the shelves is 1.50Z10 Watt, which fits into Millers 1966 estimated range of 1.4-1.7Z10 Watt, with a clear...
- Physical and Dynamic Oceanography