tidal_forcing module reference¶
Code by Robert Hallberg, August 2005, based on C-code by Harper Simmons, February, 2003, in turn based on code by Brian Arbic.
Detailed Description¶
The main subroutine in this file calculates the total tidal contribution to the geopotential, including self-attraction and loading terms and the astronomical contributions. All options are selected with entries in a file that is parsed at run-time. Overall tides are enabled with the run-time parameter ‘TIDES=True’. Tidal constituents must be individually enabled with lines like ‘TIDE_M2=True’. This file has default values of amplitude, frequency, Love number, and phase at time 0 for the Earth’s M2, S2, N2, K2, K1, O1, P1, Q1, MF, and MM tidal constituents, but the frequency, amplitude and phase ant time 0 for each constituent can be changed at run time by setting variables like TIDE_M2_FREQ, TIDE_M2_AMP and TIDE_M2_PHASE_T0 (for M2).
In addition, approaches to calculate self-attraction and loading due to tides (harmonics of astronomical forcing frequencies) are provided. TIDAL_SAL_FROM_FILE can be set to read the phase and amplitude of the tidal SAL. USE_PREVIOUS_TIDES may be useful in combination with the scalar approximation to iterate the SAL to convergence (for details, see Arbic et al., 2004, DSR II). With TIDAL_SAL_FROM_FILE or USE_PREVIOUS_TIDES, a list of input files must be provided to describe each constituent’s properties from a previous solution. The online SAL calculations that are functions of SSH (rather should be bottom pressure anmoaly), either a scalar approximation or with spherical harmonic transforms, are located in MOM_self_attr_load.