def calc_crevasse_dep(dx, dy, nu, dt, ch_depth, riv_i, riv_j, n,
sea_level, slope, loc):
"""Calculate crevasse splay deposition rate."""
beach_len = find_beach_length_riv_cell(n, (riv_i[-2], riv_j[-2]),
(riv_i[-1], riv_j[-1]), sea_level,
ch_depth, slope, dx=dx, dy=dy)
n_river = n[riv_i, riv_j]
n_river[-1] = sea_level - ch_depth
s_river = get_channel_distance((riv_i, riv_j), dx=dx, dy=dy)
s_river[-1] += beach_len
dn_rc = (nu * dt) * solve_second_derivative(s_river, n_river)
# average deposition in 3 cells above 'breach' to find
# crevasse splay deposition rate
if len(dn_rc[:loc]) >= 3:
splay_dep = np.average(dn_rc[loc-3:loc])
else: splay_dep = dn_rc[loc-1]
if splay_dep < 0:
splay_dep = 0
return splay_dep
def smooth_rc(dx, dy, nu, dt, riv_i, riv_j, n):
"""Smooth river channel elevations using the diffusion equation.
Parameters
----------
dx : float
Spacing of grid columns.
dy : float
Spacing of grid rows.
nu : float
Diffusion coefficient.
dt : float
Time step (in seconds).
riv_i : ndarray
Row indices for the river path.
riv_j : ndarray
Column indices for the river path.
n : ndarray
2D array of grid elevations.
"""
# NOTE: Divide by dx to match the old way, but I don't think this is
# correct.
# nu /= dx
# KMR 8/24/15: don't need to divide by dx anymore, diffusion coeff
# should be fixed with new calculation
n_river = n[riv_i, riv_j]
s_river = get_channel_distance((riv_i, riv_j), dx=dx, dy=dy)
dn_rc = (nu * dt) * solve_second_derivative(s_river, n_river)
n[riv_i[1:-1], riv_j[1:-1]] += dn_rc
return
def smooth_rc(dx, dy, nu, dt, ch_depth, riv_i, riv_j, n, sea_level, slope):
"""Smooth river channel elevations using the diffusion equation.
Parameters
----------
dx : float
Spacing of grid columns.
dy : float
Spacing of grid rows.
nu : float
Diffusion coefficient.
dt : float
Time step (in seconds).
riv_i : ndarray
Row indices for the river path.
riv_j : ndarray
Column indices for the river path.
n : ndarray
2D array of grid elevations.
"""
beach_len = find_beach_length_riv_cell(n, (riv_i[-2], riv_j[-2]),
(riv_i[-1], riv_j[-1]), sea_level,
ch_depth, slope, dx=dx, dy=dy)
n_river = n[riv_i, riv_j]
n_river[-1] = sea_level - ch_depth
s_river = get_channel_distance((riv_i, riv_j), dx=dx, dy=dy)
s_river[-1] += beach_len
dn_rc = (nu * dt) * solve_second_derivative(s_river, n_river)
n[riv_i[1:-1], riv_j[1:-1]] += dn_rc
return dn_rc
