def __init__(self,
time_frame,
start_location,
start_velocity=(0, 0),
**kwargs):
"""This class sets up and runs the components necessary to run an iceberg drift simulation.
Args:
time_frame (tuple of numpy.datetime64): start time, end time for the simulation.
start_location (tuple of float): starting position (latitude, longitude) for the simulation.
Kwargs:
start_velocity (tuple of float): starting velocity (vx, vy) in m/s.
time_step (numpy.timedelta64): Time step in seconds.
drift_model (function): The drift model function.
time_stepper (function): The numerical integrator function.
ocean_model (str): Name of ocean model. Can be ECMWF or HYCOM.
atmosphere_model (str): Name of the atmosphere model. Can be ECMWF or NARR.
iceberg_size (str or tuple of float): size class for the iceberg or dims (waterline length, sail height).
iceberg_shape (str): shape class for the iceberg.
"""
self.start_location = start_location
self.time_frame = time_frame
self.start_velocity = start_velocity
self.time_step = kwargs.pop('time_step', np.timedelta64(300, 's'))
self.drift_model = kwargs.pop('drift_model',
drift.newtonian_drift_wrapper)
self.time_stepper = kwargs.pop('time_stepper', timesteppers.euler)
self.ocean_model = kwargs.pop('ocean_model', 'ECMWF')
self.atmosphere_model = kwargs.pop('atmosphere_model', 'NARR')
self.ocean = metocean.Ocean(self.time_frame, model=self.ocean_model)
self.atmosphere = metocean.Atmosphere(self.time_frame,
model=self.atmosphere_model)
self.iceberg_size = kwargs.pop('iceberg_size', 'LG')
self.iceberg_shape = kwargs.pop('iceberg_shape', 'TAB')
self.iceberg = iceberg.quickstart(self.time_frame[0],
self.start_location,
velocity=self.start_velocity,
size=self.iceberg_size,
shape=self.iceberg_shape)
self.results = {}
def reload_ocean(self):
self.ocean = metocean.Ocean(self.time_frame, model=self.ocean_model)
def set_constant_current(self, constants):
self.ocean = metocean.Ocean(self.time_frame,
model=self.ocean_model,
constants=constants)
def run_simulation(time_frame, start_location, start_velocity=(0, 0),
**kwargs):
time_step = kwargs.pop('time_step', np.timedelta64(300, 's'))
time_stepper = kwargs.pop('time_stepper', timesteppers.euler)
drift_model = kwargs.pop('drift_model', drift.newtonian_drift_wrapper)
ocean_model = kwargs.pop('ocean_model', 'ECMWF')
atmosphere_model = kwargs.pop('atmosphere_model', 'NARR')
start_time, end_time = time_frame
dt = time_step.item().total_seconds()
nt = int(
np.timedelta64(end_time - start_time, 's').item().total_seconds() / dt)
size = kwargs.pop('iceberg_size', 'LG')
shape = kwargs.pop('iceberg_shape', 'TAB')
iceberg_ = kwargs.pop(
'iceberg',
iceberg.quickstart(start_time,
start_location,
velocity=start_velocity,
size=size,
shape=shape))
current_constants = kwargs.pop('current_constants', None)
wind_constants = kwargs.pop('wind_constants', None)
ocean = kwargs.pop(
'ocean',
metocean.Ocean(time_frame,
model=ocean_model,
constants=current_constants))
atmosphere = kwargs.pop(
'atmosphere',
metocean.Atmosphere(time_frame,
model=atmosphere_model,
constants=wind_constants))
# Initialize arrays
times = np.zeros(nt, dtype='datetime64[ns]')
if drift_model is drift.newtonian_drift_wrapper:
results = {
'latitude': np.zeros(nt),
'longitude': np.zeros(nt),
'iceberg_eastward_velocity': np.zeros(nt),
'iceberg_northward_velocity': np.zeros(nt)
}
kwargs = {
'form_drag_coefficient_in_air':
kwargs.pop('Ca', iceberg_.FORM_DRAG_COEFFICIENT_IN_AIR),
'form_drag_coefficient_in_water':
kwargs.pop('Cw', iceberg_.FORM_DRAG_COEFFICIENT_IN_WATER),
'skin_drag_coefficient_in_air':
iceberg_.SKIN_DRAG_COEFFICIENT_IN_AIR,
'skin_drag_coefficient_in_water':
iceberg_.SKIN_DRAG_COEFFICIENT_IN_WATER,
'sail_area':
iceberg_.geometry.sail_area,
'keel_area':
iceberg_.geometry.keel_area,
'top_area':
iceberg_.geometry.waterline_length**2,
'bottom_area':
iceberg_.geometry.bottom_area,
'mass':
kwargs.pop('mass', iceberg_.geometry.mass),
'latitude':
iceberg_.latitude,
'ekman':
kwargs.pop('ekman', False),
'depth_vec':
kwargs.pop('depth_vec', np.arange(0, -110, -10)),
'time_step':
time_step,
'eastward_current':
ocean.current.eastward_velocities,
'northward_current':
ocean.current.northward_velocities,
'eastward_wind':
atmosphere.wind.eastward_velocities,
'northward_wind':
atmosphere.wind.northward_velocities,
'log':
kwargs.pop('log', None),
'current_interpolator':
ocean.current.interpolate,
'wind_interpolator':
atmosphere.wind.interpolate
}
else:
results = {'latitude': np.zeros(nt), 'longitude': np.zeros(nt)}
kwargs = {
'form_drag_coefficient_in_air':
kwargs.pop('Ca', iceberg_.FORM_DRAG_COEFFICIENT_IN_AIR),
'form_drag_coefficient_in_water':
kwargs.pop('Cw', iceberg_.FORM_DRAG_COEFFICIENT_IN_WATER),
'waterline_length':
iceberg_.geometry.waterline_length,
'time_step':
time_step,
'eastward_current':
ocean.current.eastward_velocities,
'northward_current':
ocean.current.northward_velocities,
'eastward_wind':
atmosphere.wind.eastward_velocities,
'northward_wind':
atmosphere.wind.northward_velocities,
'current_interpolator':
ocean.current.interpolate,
'wind_interpolator':
atmosphere.wind.interpolate
}
for i in range(nt):
times[i] = iceberg_.time
results['latitude'][i] = iceberg_.latitude
results['longitude'][i] = iceberg_.longitude
if drift_model is drift.newtonian_drift_wrapper:
results['iceberg_eastward_velocity'][
i] = iceberg_.eastward_velocity
results['iceberg_northward_velocity'][
i] = iceberg_.northward_velocity
if time_stepper in (timesteppers.ab2, timesteppers.ab3):
if drift_model is drift.newtonian_drift_wrapper:
dx, dy, dvx, dvy = time_stepper(
drift_model, dt, times[:i + 1],
results['longitude'][:i + 1], results['latitude'][:i + 1],
results['iceberg_eastward_velocity'][:i + 1],
results['iceberg_northward_velocity'][:i + 1], **kwargs)
else:
dx, dy = time_stepper(drift_model, dt, times[:i + 1],
results['longitude'][:i + 1],
results['latitude'][:i + 1], **kwargs)
else:
if drift_model is drift.newtonian_drift_wrapper:
dx, dy, dvx, dvy = time_stepper(drift_model, dt, iceberg_.time,
iceberg_.longitude,
iceberg_.latitude,
iceberg_.eastward_velocity,
iceberg_.northward_velocity,
**kwargs)
else:
dx, dy = time_stepper(drift_model, dt, iceberg_.time,
iceberg_.longitude, iceberg_.latitude,
**kwargs)
if drift_model is drift.newtonian_drift_wrapper:
iceberg_.eastward_velocity += dvx
iceberg_.northward_velocity += dvy
iceberg_.time += time_step
iceberg_.latitude += tools.dy_to_dlat(dy)
iceberg_.longitude += tools.dx_to_dlon(dx, iceberg_.latitude)
xds = xr.Dataset()
for key, value in results.items():
xarr = xr.DataArray(data=value, coords=[times], dims=['time'])
xds[key] = xarr
return xds
def run_simulation(time_frame, start_location, start_velocity=(0, 0),
**kwargs):
time_step = kwargs.pop('time_step', np.timedelta64(300, 's'))
time_stepper = kwargs.pop('time_stepper', timesteppers.euler)
drift_model = kwargs.pop('drift_model', drift.newtonian_drift_wrapper)
ocean_model = kwargs.pop('ocean_model', 'ECMWF')
atmosphere_model = kwargs.pop('atmosphere_model', 'NARR')
perturb_current = kwargs.pop('perturb_current', False)
perturb_wind = kwargs.pop('perturb_wind', False)
smoothing_constant = kwargs.pop('smoothing_constant', 0.5)
start_time, end_time = time_frame
dt = time_step.item().total_seconds()
nt = int(
np.timedelta64(end_time - start_time, 's').item().total_seconds() / dt)
waterline_length = kwargs.pop('waterline_length', None)
sail_height = kwargs.pop('sail_height', None)
if waterline_length is not None and sail_height is not None:
size = waterline_length, sail_height
else:
size = kwargs.pop('iceberg_size', 'LG')
shape = kwargs.pop('iceberg_shape', 'TAB')
iceberg_ = kwargs.pop(
'iceberg',
iceberg.quickstart(start_time,
start_location,
velocity=start_velocity,
size=size,
shape=shape))
current_constants = kwargs.pop('current_constants', None)
wind_constants = kwargs.pop('wind_constants', None)
ocean = kwargs.pop(
'ocean',
metocean.Ocean(time_frame,
model=ocean_model,
constants=current_constants))
atmosphere = kwargs.pop(
'atmosphere',
metocean.Atmosphere(time_frame,
model=atmosphere_model,
constants=wind_constants))
# Initialize arrays
times = np.zeros(nt, dtype='datetime64[ns]')
if drift_model is drift.newtonian_drift_wrapper:
results = {
'latitude': np.zeros(nt),
'longitude': np.zeros(nt),
'iceberg_eastward_velocity': np.zeros(nt),
'iceberg_northward_velocity': np.zeros(nt)
}
kwargs = {
'form_drag_coefficient_in_air':
kwargs.pop('Ca', iceberg_.FORM_DRAG_COEFFICIENT_IN_AIR),
'form_drag_coefficient_in_water':
kwargs.pop('Cw', iceberg_.FORM_DRAG_COEFFICIENT_IN_WATER),
'skin_drag_coefficient_in_air':
iceberg_.SKIN_DRAG_COEFFICIENT_IN_AIR,
'skin_drag_coefficient_in_water':
iceberg_.SKIN_DRAG_COEFFICIENT_IN_WATER,
'sail_area':
iceberg_.geometry.sail_area,
'keel_area':
iceberg_.geometry.keel_area,
'top_area':
iceberg_.geometry.waterline_length**2,
'bottom_area':
iceberg_.geometry.bottom_area,
'mass':
kwargs.pop('mass', iceberg_.geometry.mass),
'latitude':
iceberg_.latitude,
'ekman':
kwargs.pop('ekman', False),
'depth_vec':
kwargs.pop('depth_vec', np.arange(0, -110, -10)),
'time_step':
time_step,
'eastward_current':
ocean.current.eastward_velocities,
'northward_current':
ocean.current.northward_velocities,
'eastward_wind':
atmosphere.wind.eastward_velocities,
'northward_wind':
atmosphere.wind.northward_velocities,
'log':
kwargs.pop('log', None),
'current_interpolator':
ocean.current.interpolate,
'wind_interpolator':
atmosphere.wind.interpolate,
'current_sample':
np.array([0, 0]),
'wind_sample':
np.array([0, 0])
}
else:
results = {'latitude': np.zeros(nt), 'longitude': np.zeros(nt)}
kwargs = {
'form_drag_coefficient_in_air':
kwargs.pop('Ca', iceberg_.FORM_DRAG_COEFFICIENT_IN_AIR),
'form_drag_coefficient_in_water':
kwargs.pop('Cw', iceberg_.FORM_DRAG_COEFFICIENT_IN_WATER),
'waterline_length':
iceberg_.geometry.waterline_length,
'time_step':
time_step,
'eastward_current':
ocean.current.eastward_velocities,
'northward_current':
ocean.current.northward_velocities,
'eastward_wind':
atmosphere.wind.eastward_velocities,
'northward_wind':
atmosphere.wind.northward_velocities,
'current_interpolator':
ocean.current.interpolate,
'wind_interpolator':
atmosphere.wind.interpolate,
'current_sample':
np.array([0, 0]),
'wind_sample':
np.array([0, 0])
}
current_correction_samples = read_csv(
'/home/evankielley/current_correction_samples.csv')
current_correction_samples = current_correction_samples.drop(
columns='Unnamed: 0')
wind_correction_samples = read_csv(
'/home/evankielley/wind_correction_samples.csv')
wind_correction_samples = wind_correction_samples.drop(
columns='Unnamed: 0')
for i in range(nt):
times[i] = iceberg_.time
results['latitude'][i] = iceberg_.latitude
results['longitude'][i] = iceberg_.longitude
if perturb_current:
previous_current_sample = kwargs.get('current_sample')
current_correction_sample = -1 * current_correction_samples.iloc[
np.random.randint(0, len(current_correction_samples))].values
new_current_sample = previous_current_sample * (
1 - smoothing_constant
) + current_correction_sample * smoothing_constant
# new_current_sample = ocean.current.sample(previous_sample=previous_current_sample, alpha=smoothing_constant)
kwargs['current_sample'] = new_current_sample
if perturb_wind:
previous_wind_sample = kwargs.get('wind_sample')
wind_correction_sample = -1 * wind_correction_samples.iloc[
np.random.randint(0, len(wind_correction_samples))].values
new_wind_sample = previous_wind_sample * (
1 - smoothing_constant
) + wind_correction_sample * smoothing_constant
# new_wind_sample = atmosphere.wind.sample(previous_sample=previous_wind_sample, alpha=smoothing_constant)
kwargs['wind_sample'] = new_wind_sample
if drift_model is drift.newtonian_drift_wrapper:
results['iceberg_eastward_velocity'][
i] = iceberg_.eastward_velocity
results['iceberg_northward_velocity'][
i] = iceberg_.northward_velocity
if time_stepper in (timesteppers.ab2, timesteppers.ab3):
if drift_model is drift.newtonian_drift_wrapper:
dx, dy, dvx, dvy = time_stepper(
drift_model, dt, times[:i + 1],
results['longitude'][:i + 1], results['latitude'][:i + 1],
results['iceberg_eastward_velocity'][:i + 1],
results['iceberg_northward_velocity'][:i + 1], **kwargs)
else:
dx, dy = time_stepper(drift_model, dt, times[:i + 1],
results['longitude'][:i + 1],
results['latitude'][:i + 1], **kwargs)
else:
if drift_model is drift.newtonian_drift_wrapper:
dx, dy, dvx, dvy = time_stepper(drift_model, dt, iceberg_.time,
iceberg_.longitude,
iceberg_.latitude,
iceberg_.eastward_velocity,
iceberg_.northward_velocity,
**kwargs)
else:
dx, dy = time_stepper(drift_model, dt, iceberg_.time,
iceberg_.longitude, iceberg_.latitude,
**kwargs)
if drift_model is drift.newtonian_drift_wrapper:
iceberg_.eastward_velocity += dvx
iceberg_.northward_velocity += dvy
iceberg_.time += time_step
iceberg_.latitude += tools.dy_to_dlat(dy)
iceberg_.longitude += tools.dx_to_dlon(dx, iceberg_.latitude)
xds = xr.Dataset()
for key, value in results.items():
xarr = xr.DataArray(data=value, coords=[times], dims=['time'])
xds[key] = xarr
return xds