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Update to #8699. There was another #def variable holding Earth's grav. #8703

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Merged
joa-quim merged 1 commit into from
Mar 25, 2025
Merged

Update to #8699. There was another #def variable holding Earth's grav. #8703

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3 changes: 1 addition & 2 deletions src/grdfft.c
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Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,6 @@ GMT_LOCAL unsigned int grdfft_do_azimuthal_derivative (struct GMT_GRID *Grid, do
/* Now obsolete but left for backwards compatibility. Users are encouraged to use gravfft */
#define POISSONS_RATIO 0.25
#define YOUNGS_MODULUS 1.0e11 /* Pascal = Nt/m**2 */
#define NORMAL_GRAVITY 9.806199203 /* m/s**2 */

GMT_LOCAL unsigned int grdfft_do_isostasy (struct GMT_GRID *Grid, struct GRDFFT_CTRL *Ctrl, double *par, struct GMT_FFT_WAVENUMBER *K) {
/* Do the isostatic response function convolution in the Freq domain.
Expand Down Expand Up @@ -255,7 +254,7 @@ GMT_LOCAL unsigned int grdfft_do_isostasy (struct GMT_GRID *Grid, struct GRDFFT_
}

rigidity_d = (YOUNGS_MODULUS * pow (te, 3.0)) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
d_over_restoring_force = rigidity_d / ((rm - ri) * NORMAL_GRAVITY);
d_over_restoring_force = rigidity_d / ((rm - ri) * Ctrl->M.mgal_at_45 * 1e-5);

for (k = 0; k < Grid->header->size; k += 2) {
mk = gmt_fft_get_wave (k, K);
Expand Down
28 changes: 16 additions & 12 deletions src/potential/gravfft.c
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ struct GRAVFFT_CTRL {
} I;
struct GRAVFFT_M { /* -M<mgal_at_45> */
bool active;
double mgal_at_45;
double mgal_at_45, normal_gravity;
} M;
struct GRAVFFT_N { /* -N[f|q|s<n_columns>/<n_rows>][+e|m|n][+t<width>][+w[<suffix>]][+z[p]] */
bool active;
Expand Down Expand Up @@ -137,7 +137,7 @@ struct GRAVFFT_CTRL {
#endif

#define YOUNGS_MODULUS 7.0e10 /* Pascal = Nt/m**2 */
#define NORMAL_GRAVITY 9.806199203 /* Moritz's 1980 IGF value for gravity at 45 degrees latitude (m/s) */
//#define NORMAL_GRAVITY 9.806199203 /* Moritz's 1980 IGF value for gravity at 45 degrees latitude (m/s) */
#define POISSONS_RATIO 0.25

static bool sphericity = false;
Expand Down Expand Up @@ -322,6 +322,7 @@ static int parse (struct GMT_CTRL *GMT, struct GRAVFFT_CTRL *Ctrl, struct GMT_OP
case 'M': /* Miligals at 45 degrees */
n_errors += gmt_M_repeated_module_option(API, Ctrl->M.active);
sscanf(opt->arg, "%lf", &Ctrl->M.mgal_at_45);
Ctrl->M.normal_gravity = Ctrl->M.mgal_at_45 * 1e-5;
break;
case 'N':
n_errors += gmt_M_repeated_module_option (API, Ctrl->N.active);
Expand Down Expand Up @@ -423,7 +424,10 @@ static int parse (struct GMT_CTRL *GMT, struct GRAVFFT_CTRL *Ctrl, struct GMT_OP
!(Ctrl->F.mode == GRAVFFT_FAA || Ctrl->F.mode == GRAVFFT_GEOID),
"Theoretical admittances are only defined for FAA or GEOID.\n");

if (!Ctrl->M.active) Ctrl->M.mgal_at_45 = 980619.9203; /* Moritz's 1980 IGF value for gravity in mGal at 45 degrees latitude */
if (!Ctrl->M.active) {
Ctrl->M.mgal_at_45 = 980619.9203; /* Moritz's 1980 IGF value for gravity in mGal at 45 degrees latitude */
Ctrl->M.normal_gravity = 9.806199203;
}

return (n_errors ? GMT_PARSE_ERROR : GMT_NOERROR);
}
Expand Down Expand Up @@ -875,7 +879,7 @@ GMT_LOCAL void gravfft_do_isostasy (struct GMT_CTRL *GMT, struct GMT_GRID *Grid,
}
GMT_Report (GMT->parent, GMT_MSG_DEBUG, "Using effective load density rho_l = %g and Airy boost factor A = %g\n", rho_load, A);
rigidity_d = (YOUNGS_MODULUS * Ctrl->T.te * Ctrl->T.te * Ctrl->T.te) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
d_over_restoring_force = rigidity_d / ( (Ctrl->T.rhom - rho_load) * NORMAL_GRAVITY);
d_over_restoring_force = rigidity_d / ( (Ctrl->T.rhom - rho_load) * Ctrl->M.normal_gravity);
airy_ratio = -A * (rho_load - Ctrl->T.rhow)/(Ctrl->T.rhom - rho_load);

if (Ctrl->T.te == 0.0) { /* Airy isostasy; scale global variable scale_out and return */
Expand Down Expand Up @@ -1120,7 +1124,7 @@ GMT_LOCAL void gravfft_load_from_below_admitt(struct GMT_CTRL *GMT, struct GRAVF

delta_k /= TWO_PI; /* Use frequency, not wavenumber */
D = (YOUNGS_MODULUS * Ctrl->T.te * Ctrl->T.te * Ctrl->T.te) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
alfa = pow (TWO_PI, 4.) * D / (NORMAL_GRAVITY * Ctrl->T.rho_mc);
alfa = pow (TWO_PI, 4.) * D / (Ctrl->M.normal_gravity * Ctrl->T.rho_mc);

for (k = 0; k < nk; k++) {
freq = (k + 1) * delta_k;
Expand All @@ -1129,7 +1133,7 @@ GMT_LOCAL void gravfft_load_from_below_admitt(struct GMT_CTRL *GMT, struct GRAVF
if (Ctrl->F.mode == GRAVFFT_FAA)
t1 *= 1.0e5; /* to have it in mGals */
else /* Must be the GEOID case */
t1 /= (NORMAL_GRAVITY * freq * TWO_PI);
t1 /= (Ctrl->M.normal_gravity * freq * TWO_PI);
t2 = Ctrl->T.rho_cw * exp(-TWO_PI * freq * Ctrl->misc.z_level) +
Ctrl->T.rho_mc * exp(-TWO_PI * freq * Ctrl->Z.zm);
t3 = -(Ctrl->T.rho_mw + Ctrl->T.rho_mc * pow(freq,4.) * alfa) * exp(-TWO_PI * freq * Ctrl->Z.zl);
Expand All @@ -1156,7 +1160,7 @@ GMT_LOCAL void gravfft_load_from_top_admitt (struct GMT_CTRL *GMT, struct GRAVFF

delta_k /= TWO_PI; /* Use frequency, not wavenumber */
D = (YOUNGS_MODULUS * Ctrl->T.te * Ctrl->T.te * Ctrl->T.te) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
alfa = pow (TWO_PI,4.) * D / (NORMAL_GRAVITY * Ctrl->T.rho_mc);
alfa = pow (TWO_PI,4.) * D / (Ctrl->M.normal_gravity * Ctrl->T.rho_mc);

for (k = 0; k < nk; k++) {
freq = (k + 1) * delta_k;
Expand All @@ -1165,7 +1169,7 @@ GMT_LOCAL void gravfft_load_from_top_admitt (struct GMT_CTRL *GMT, struct GRAVFF
if (Ctrl->F.mode == GRAVFFT_FAA)
t1 *= 1.0e5; /* to have it in mGals */
else /* Must be the GEOID case */
t1 /= (NORMAL_GRAVITY * freq * TWO_PI);
t1 /= (Ctrl->M.normal_gravity * freq * TWO_PI);
t2 = exp(-TWO_PI * freq * Ctrl->misc.z_level) - exp(-TWO_PI * freq * Ctrl->Z.zm) / (1 + alfa*pow(freq,4.));
z_from_top[k] = t1 * Ctrl->T.rho_cw * t2;
}
Expand All @@ -1188,7 +1192,7 @@ GMT_LOCAL void gravfft_load_from_top_grid (struct GMT_CTRL *GMT, struct GMT_GRID
p = n - 1.0;

D = (YOUNGS_MODULUS * Ctrl->T.te * Ctrl->T.te * Ctrl->T.te) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
alfa = pow(TWO_PI,4.) * D / (NORMAL_GRAVITY * Ctrl->T.rho_mc);
alfa = pow(TWO_PI,4.) * D / (Ctrl->M.normal_gravity * Ctrl->T.rho_mc);
raised[0] = 0.0f; raised[1] = 0.0f;

for (k = 0; k < Grid->header->size; k+= 2) {
Expand All @@ -1213,7 +1217,7 @@ GMT_LOCAL void gravfft_load_from_top_grid (struct GMT_CTRL *GMT, struct GMT_GRID
datac[k+1] += (gmt_grdfloat) ((Ctrl->T.rho_cw * t1 * t2) * t / f * raised[k+1]);
break;
case GRAVFFT_GEOID:
if (mk > 0.0) t1 /= (NORMAL_GRAVITY * mk * TWO_PI);
if (mk > 0.0) t1 /= (Ctrl->M.normal_gravity * mk * TWO_PI);
datac[k] += (gmt_grdfloat) ((Ctrl->T.rho_cw * t1 * t2) * t / f * raised[k]);
datac[k+1] += (gmt_grdfloat) ((Ctrl->T.rho_cw * t1 * t2) * t / f * raised[k+1]);
break;
Expand Down Expand Up @@ -1259,7 +1263,7 @@ GMT_LOCAL void gravfft_load_from_below_grid (struct GMT_CTRL *GMT, struct GMT_GR
p = n - 1.0;

D = (YOUNGS_MODULUS * Ctrl->T.te * Ctrl->T.te * Ctrl->T.te) / (12.0 * (1.0 - POISSONS_RATIO * POISSONS_RATIO));
alfa = pow(TWO_PI,4.) * D / (NORMAL_GRAVITY * Ctrl->T.rho_mc);
alfa = pow(TWO_PI,4.) * D / (Ctrl->M.normal_gravity * Ctrl->T.rho_mc);
raised[0] = 0.0f; raised[1] = 0.0f;

for (k = 0; k < Grid->header->size; k+= 2) {
Expand All @@ -1275,7 +1279,7 @@ GMT_LOCAL void gravfft_load_from_below_grid (struct GMT_CTRL *GMT, struct GMT_GR
if (Ctrl->F.mode == GRAVFFT_FAA)
t1 *= 1.0e5; /* to have it in mGals */
else /* Must be the GEOID case */
t1 /= (NORMAL_GRAVITY * mk * TWO_PI);
t1 /= (Ctrl->M.normal_gravity * mk * TWO_PI);
t2 = Ctrl->T.rho_cw * exp(-TWO_PI * mk * Ctrl->misc.z_level) +
Ctrl->T.rho_mc * exp(-TWO_PI * mk * Ctrl->Z.zm);
t3 = -(Ctrl->T.rho_mw + Ctrl->T.rho_mc * pow(mk,4.) * alfa) * exp(-TWO_PI * mk * Ctrl->Z.zl);
Expand Down
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