NAME
sotid - library for computing site displacements due to solid Earth
tides
SYNTAX
SOTID_SET ( GEN_LOVE, MODEL_2D, ORDER_2D, ZERO_FREQ_LOVE, MODEL_3D,
TIDCNF, IUER )
INCLUDE 'sotid_type.i'
TYPE ( TIDCNF__STRU ) :: TIDCNF
INTEGER*4 GEN_LOVE, MODEL_2D, ORDER_2D, ZERO_FREQ_LOVE,
MODEL_3D, IUER
SOTID_PRE ( L_STA, C_STA, R_CFS, TIDCNF, STATID, IUER )
INCLUDE 'sotid_type.i'
INTEGER*4 L_STA, IUER
CHARACTER C_STA(L_STA)*(SOTID__NAM_LEN)
REAL*8 R_CFS(3,SOTID__MAX_STA)
TYPE ( STATID__STRU ) :: STATID(L_STA)
TYPE ( TIDCNF__STRU ) :: TIDCNF
SOTID_TIM ( MJD, TAI, UT1_M_TAI, TIDCNF, TIMTID, IUER )
INCLUDE 'sotid_type.i'
INTEGER*4 MJD, IUER
REAL*8 TAI, UT1_M_TAI
TYPE ( TIDCNF__STRU ) :: TIDCNF
TYPE ( TIMTID__STRU ) :: TIMTID !
SUBROUTINE SOTID_DSP ( TIDCNF, TIMTID, STATID, D_REN )
INCLUDE 'sotid_type.i'
REAL*8 D_REN(3)
TYPE ( TIDCNF__STRU ) :: TIDCNF
TYPE ( TIMTID__STRU ) :: TIMTID
TYPE ( STATID__STRU ) :: STATID !
FUNCTION SOTID_INQ ( REQUEST, TIDCNF, OUT_STR, OUT_STR_LEN, IUER )
INCLUDE 'sotid_type.i'
INTEGER*4 SOTID_INQ
TYPE ( TIDCNF__STRU ) :: TIDCNF
INTEGER*4 REQUEST, OUT_STR_LEN, IUER
CHARACTER OUT_STR*(*)
END FUNCTION SOTID_INQ
DESCRIPTION
Subroutine sotid_set sets configuration for sotid software. Values
of each configuration parameter are checked and if the checks are OK,
they are put in the field of the object TIDCNF. Configuration
parameters defines:
-- which generalized Love numbers are to be used;
-- which model for the Love numbers of the second degree is to
be applied;
-- tidal waves of which order of the second degree should be
taken into account: zonal, diurnal, semi-diurnal or their
combination. Normally, all orders, zonal, diurnal, semi-diurnal
are used.
-- which Love numbers for the tides of the zeroth frequency
should be used;
which model for the Love numbers of the third degree is to be
applied.
Function sotid_inq makes an inquiry of the current SOTID
configuration and returns the status. One inquiry at the time can be
made. sotid_inq returns the value of the requested parameter as well
as the output string with description. The following requests are
recognized:
SOTID__REQ_MODEL_2D -- what is the model for computation of the
tides of the second degree.
SOTID__REQ_MODEL_3D -- what is the model for computation of the
tides of the third degree.
SOTID__REQ_GEN_LOVE -- which generalized Love numbers to take
into account.
SOTID__REQ_ORDER_2D -- waves of which order, degree 2 to take
into account.
SOTID__REQ_ZF_LOVE -- what is the model for Love numbers for
the zero frequency.
SOTID__REQ_N_STA -- for how many stations STATID records were
set up.
SOTID__REQ_NW_D2 -- how many tidal waves of the potential
degree 2 are used.
SOTID__REQ_NW_D3 -- how many tidal waves of the potential
degree 3 are used.
Subroutine sotid_pre computes time-independent arguments used for
computations of site displacements caused by the solid Earth tides.
These arguments depend on crust-fixed station positions. Routine
sotid_pre puts these time-independent arguments into the STATID
arrays.
over harmonics of the tidal potential of the second and the third
degree. These quantities are used in computation of the displacements
due to the Earth solid tides, pole tides and ocean loading. They are
put in the object TIDCNF. Routine SOTID_TIM should be called each time
for the new moment of time before SOTID_DSP which computes tidal
displacement for the specific moment of time specified in the call to
SOTID_TIM for the specific station. Truncated harmonic expansion HW95
is used for computation.
Subroutine sotid_dsp computes site displacements due to the Earth's
solid tides of the second and third degree using harmonic expansion of
tidal potential according to the configuration parameters of sotid. It
is assumed that session-dependent and time-dependent intermediary
quantities were calculated before by calls of sotid_set, sotid_pre and
sotid_tim.
FILES
Package sotid is compiled with include files which keep coefficients
of the truncated harmonic expansion of the tide-generating potential.
This expansion is derived from the hw95 expansion in Poisson series.
Names of the files with these coefficients are defined during
compilation and kept in sotid_data.i include file. The files with
these coefficients may be created with using program hw95_out which is
the part of sotid. hw95_out will require original file of Hartmann-
Wenzel expansion hw95. This file is not distributed with sotid and can
be downloaded from http://bowie.gsfc.nasa.gov/hw95/
AUTHOR
Leonid Petrov ( pet@leo.gsfc.nasa.gov )
Last update: 2002.07.17
SEE ALSO
Home Web page: http://gemini.gsfc.nasa.gov/sotid
References:
Dehant V., Defraigne P. and Wahr J.M., 1999, "Tides for a
convective Earth.", J. Geophys. Res., 104, B1, pp. 1035-1058.
Hartmann T., and H-G. Wenzel "The HW95 tidal potential
catalogue", Geophysical Research Letters", 22(24), p. 3553-
3556, 1995.
Mathews, P.M., B.A. Buffet, I.I. Shapiro "Love number for a
rotating spheroidal Earth: New definitions and numerical values",
GRL, 22(5), pp. 5579-582, 1995.
Mathews, P.M., Love numbers and gravimetric factor for diurnal
tides, Journal of the Geodetic Society of Japan, 47}(1) , 231-
Melchior, P., "The Tides of the Planet Earth", Oxford, 1983.
Petrov, L., "Study of harmonic site position variations
determined by VLBI", submitted to J. Geophys. Res.,
10.1029/2002JB001801, 2002.
Wahr, J.M., "Body tides on an elliptical, elastic, rotating and
oceanless Earth", Geophysical Journal of Royal Astronomical
Society,
64(3), pp. 677-703, 1981.
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