def test_lon_normalize(self):
"""Test the longitude normalization function"""
data = np.array([-180, 20.1, -30, 190, -350])
# test in place operation
lon_normalize(data)
self.assertTrue(np.allclose(data, [180, 20.1, -30, -170, 10]))
# test with specific center and return value
data = lon_normalize(data, center=-170)
self.assertTrue(np.allclose(data, [-180, -339.9, -30, -170, 10]))
def test_lon_normalize(self):
"""Test the longitude normalization function"""
data = np.array([-180, 20.1, -30, 190, -350])
# test in place operation
lon_normalize(data)
np.testing.assert_array_almost_equal(data, [180, 20.1, -30, -170, 10])
# test with specific center and return value
data = lon_normalize(data, center=-170)
np.testing.assert_array_almost_equal(data,
[-180, -339.9, -30, -170, 10])
# test with center determined automatically (which is 280.05)
data = lon_normalize(data, center=None)
np.testing.assert_array_almost_equal(data, [180, 380.1, 330, 190, 370])
def select(self, reg_id=None, extent=None, sel_cen=None):
"""Return Centroids with points in the given reg_id or within mask
Parameters
----------
reg_id : int
region to filter according to region_id values
extent : tuple
Format (min_lon, max_lon, min_lat, max_lat) tuple.
If min_lon > lon_max, the extend crosses the antimeridian and is
[lon_max, 180] + [-180, lon_min]
Borders are inclusive.
sel_cen : np.array
1-dim mask, overrides reg_id and extent
Returns
-------
cen : Centroids
Sub-selection of this object
"""
if sel_cen is None:
sel_cen = np.ones_like(self.region_id, dtype=bool)
if reg_id:
sel_cen &= np.isin(self.region_id, reg_id)
if extent:
lon_min, lon_max, lat_min, lat_max = extent
lon_max += 360 if lon_min > lon_max else 0
lon_normalized = u_coord.lon_normalize(self.lon.copy(),
center=0.5 *
(lon_min + lon_max))
sel_cen &= ((lon_normalized >= lon_min) &
(lon_normalized <= lon_max) & (self.lat >= lat_min)
& (self.lat <= lat_max))
if not self.lat.size or not self.lon.size:
self.set_meta_to_lat_lon()
centr = Centroids()
centr.set_lat_lon(self.lat[sel_cen], self.lon[sel_cen],
self.geometry.crs)
if self.area_pixel.size:
centr.area_pixel = self.area_pixel[sel_cen]
if self.region_id.size:
centr.region_id = self.region_id[sel_cen]
if self.on_land.size:
centr.on_land = self.on_land[sel_cen]
if self.dist_coast.size:
centr.dist_coast = self.dist_coast[sel_cen]
return centr
def test_latlon_bounds(self):
"""Test latlon_bounds function"""
lat, lon = np.array([0, -2, 5]), np.array([-179, 175, 178])
bounds = latlon_bounds(lat, lon)
self.assertEqual(bounds, (175, -2, 181, 5))
bounds = latlon_bounds(lat, lon, buffer=1)
self.assertEqual(bounds, (174, -3, 182, 6))
# buffer exceeding antimeridian
lat, lon = np.array([0, -2.1, 5]), np.array([-179.5, -175, -178])
bounds = latlon_bounds(lat, lon, buffer=1)
self.assertEqual(bounds, (179.5, -3.1, 186, 6))
# longitude values need to be normalized before they lie between computed bounds:
lon_mid = 0.5 * (bounds[0] + bounds[2])
lon = lon_normalize(lon, center=lon_mid)
self.assertTrue(np.all((bounds[0] <= lon) & (lon <= bounds[2])))
# data covering almost the whole longitudinal range
lat, lon = np.linspace(-90, 90, 180), np.linspace(-180.0, 179, 360)
bounds = latlon_bounds(lat, lon)
self.assertEqual(bounds, (-179, -90, 180, 90))
bounds = latlon_bounds(lat, lon, buffer=1)
self.assertEqual(bounds, (-180, -90, 180, 90))
def compute_windfields(track, centroids, model, metric="equirect"):
"""Compute 1-minute sustained winds (in m/s) at 10 meters above ground
In a first step, centroids within reach of the track are determined so that wind fields will
only be computed and returned for those centroids.
Parameters
----------
track : xr.Dataset
Track infomation.
centroids : 2d np.array
Each row is a centroid [lat, lon].
Centroids that are not within reach of the track are ignored.
model : int
Holland model selection according to MODEL_VANG.
metric : str, optional
Specify an approximation method to use for earth distances: "equirect" (faster) or
"geosphere" (more accurate). See `dist_approx` function in `climada.util.coordinates`.
Default: "equirect".
Returns
-------
windfields : np.array of shape (npositions, nreachable, 2)
Directional wind fields for each track position on those centroids within reach
of the TC track.
reachable_centr_idx : np.array of shape (nreachable,)
List of indices of input centroids within reach of the TC track.
"""
# copies of track data
# Note that max wind records are not used in the Holland wind field models!
t_lat, t_lon, t_tstep, t_rad, t_env, t_cen = [
track[ar].values.copy() for ar in [
'lat', 'lon', 'time_step', 'radius_max_wind',
'environmental_pressure', 'central_pressure'
]
]
# start with the assumption that no centroids are within reach
npositions = t_lat.shape[0]
reachable_centr_idx = np.zeros((0, ), dtype=np.int64)
windfields = np.zeros((npositions, 0, 2), dtype=np.float64)
# the wind field model requires at least two track positions because translational speed
# as well as the change in pressure are required
if npositions < 2:
return windfields, reachable_centr_idx
# normalize longitude values (improves performance of `dist_approx` and `_close_centroids`)
mid_lon = 0.5 * sum(u_coord.lon_bounds(t_lon))
u_coord.lon_normalize(t_lon, center=mid_lon)
u_coord.lon_normalize(centroids[:, 1], center=mid_lon)
# restrict to centroids within rectangular bounding boxes around track positions
track_centr_msk = _close_centroids(t_lat, t_lon, centroids)
track_centr = centroids[track_centr_msk]
nreachable = track_centr.shape[0]
if nreachable == 0:
return windfields, reachable_centr_idx
# compute distances and vectors to all centroids
[d_centr], [v_centr] = u_coord.dist_approx(t_lat[None],
t_lon[None],
track_centr[None, :, 0],
track_centr[None, :, 1],
log=True,
normalize=False,
method=metric)
# exclude centroids that are too far from or too close to the eye
close_centr_msk = (d_centr < CENTR_NODE_MAX_DIST_KM) & (d_centr > 1e-2)
if not np.any(close_centr_msk):
return windfields, reachable_centr_idx
v_centr_normed = np.zeros_like(v_centr)
v_centr_normed[close_centr_msk] = v_centr[close_centr_msk] / d_centr[
close_centr_msk, None]
# make sure that central pressure never exceeds environmental pressure
pres_exceed_msk = (t_cen > t_env)
t_cen[pres_exceed_msk] = t_env[pres_exceed_msk]
# extrapolate radius of max wind from pressure if not given
t_rad[:] = estimate_rmw(t_rad, t_cen) * NM_TO_KM
# translational speed of track at every node
v_trans = _vtrans(t_lat, t_lon, t_tstep, metric=metric)
v_trans_norm = v_trans[0]
# adjust pressure at previous track point
prev_pres = t_cen[:-1].copy()
msk = (prev_pres < 850)
prev_pres[msk] = t_cen[1:][msk]
# compute b-value and derive (absolute) angular velocity
if model == MODEL_VANG['H1980']:
# convert recorded surface winds to gradient-level winds without translational influence
t_vmax = track.max_sustained_wind.values.copy()
t_gradient_winds = np.fmax(
0, t_vmax - v_trans_norm) / GRADIENT_LEVEL_TO_SURFACE_WINDS
hol_b = _B_holland_1980(t_gradient_winds[1:], t_env[1:], t_cen[1:])
v_ang_norm = _stat_holland_1980(d_centr[1:], t_rad[1:], hol_b,
t_env[1:], t_cen[1:], t_lat[1:],
close_centr_msk[1:])
v_ang_norm *= GRADIENT_LEVEL_TO_SURFACE_WINDS
elif model == MODEL_VANG['H08']:
# this model doesn't use the recorded surface winds
hol_b = _bs_holland_2008(v_trans_norm[1:], t_env[1:], t_cen[1:],
prev_pres, t_lat[1:], t_tstep[1:])
v_ang_norm = _stat_holland_1980(d_centr[1:], t_rad[1:], hol_b,
t_env[1:], t_cen[1:], t_lat[1:],
close_centr_msk[1:])
elif model == MODEL_VANG['H10']:
# this model doesn't use the recorded surface winds
hol_b = _bs_holland_2008(v_trans_norm[1:], t_env[1:], t_cen[1:],
prev_pres, t_lat[1:], t_tstep[1:])
t_vmax = _v_max_s_holland_2008(t_env[1:], t_cen[1:], hol_b)
hol_x = _x_holland_2010(d_centr[1:], t_rad[1:], t_vmax, hol_b,
close_centr_msk[1:])
v_ang_norm = _stat_holland_2010(d_centr[1:], t_vmax, t_rad[1:], hol_b,
close_centr_msk[1:], hol_x)
else:
raise NotImplementedError
# vectorial angular velocity
hemisphere = 'N'
if np.count_nonzero(t_lat < 0) > np.count_nonzero(t_lat > 0):
hemisphere = 'S'
v_ang_rotate = [1.0, -1.0] if hemisphere == 'N' else [-1.0, 1.0]
v_ang_dir = np.array(v_ang_rotate)[..., :] * v_centr_normed[1:, :, ::-1]
v_ang = np.zeros_like(v_ang_dir)
v_ang[close_centr_msk[1:]] = v_ang_norm[close_centr_msk[1:], None] \
* v_ang_dir[close_centr_msk[1:]]
# Influence of translational speed decreases with distance from eye.
# The "absorbing factor" is according to the following paper (see Fig. 7):
#
# Mouton, F., & Nordbeck, O. (1999). Cyclone Database Manager. A tool
# for converting point data from cyclone observations into tracks and
# wind speed profiles in a GIS. UNED/GRID-Geneva.
# https://unepgrid.ch/en/resource/19B7D302
#
t_rad_bc = np.broadcast_arrays(t_rad[:, None], d_centr)[0]
v_trans_corr = np.zeros_like(d_centr)
v_trans_corr[close_centr_msk] = np.fmin(
1, t_rad_bc[close_centr_msk] / d_centr[close_centr_msk])
# add angular and corrected translational velocity vectors
v_full = v_trans[1][1:, None, :] * v_trans_corr[1:, :, None] + v_ang
v_full[np.isnan(v_full)] = 0
windfields = np.zeros((npositions, nreachable, 2), dtype=np.float64)
windfields[1:, :, :] = v_full
[reachable_centr_idx] = track_centr_msk.nonzero()
return windfields, reachable_centr_idx
def set_from_tracks(self,
tracks,
centroids=None,
description='',
model='H08',
ignore_distance_to_coast=False,
store_windfields=False,
metric="equirect"):
"""
Clear and fill with windfields from specified tracks.
This function sets the `TropCyclone.intensity` attribute to contain, for each centroid,
the maximum wind speed (1-minute sustained winds at 10 meters above ground) experienced
over the whole period of each TC event in m/s. The wind speed is set to 0 if it doesn't
exceed the threshold in `TropCyclone.intensity_thres`.
The `TropCyclone.category` attribute is set to the value of the `category`-attribute
of each of the given track data sets.
The `TropCyclone.basin` attribute is set to the genesis basin for each event, which
is the first value of the `basin`-variable in each of the given track data sets.
Optionally, the time dependent, vectorial winds can be stored using the `store_windfields`
function parameter (see below).
Parameters
----------
tracks : TCTracks
Tracks of storm events.
centroids : Centroids, optional
Centroids where to model TC. Default: global centroids at 360 arc-seconds resolution.
description : str, optional
Description of the event set. Default: "".
model : str, optional
Parametric wind field model to use: one of "H1980" (the prominent Holland 1980 model),
"H08" (Holland 1980 with b-value from Holland 2008), or "H10" (Holland et al. 2010).
Default: "H08".
ignore_distance_to_coast : boolean, optional
If True, centroids far from coast are not ignored. Default: False.
store_windfields : boolean, optional
If True, the Hazard object gets a list `windfields` of sparse matrices. For each track,
the full velocity vectors at each centroid and track position are stored in a sparse
matrix of shape (npositions, ncentroids * 2) that can be reshaped to a full ndarray
of shape (npositions, ncentroids, 2). Default: False.
metric : str, optional
Specify an approximation method to use for earth distances:
* "equirect": Distance according to sinusoidal projection. Fast, but inaccurate for
large distances and high latitudes.
* "geosphere": Exact spherical distance. Much more accurate at all distances, but slow.
Default: "equirect".
Raises
------
ValueError
"""
num_tracks = tracks.size
if centroids is None:
centroids = Centroids.from_base_grid(res_as=360, land=False)
if not centroids.coord.size:
centroids.set_meta_to_lat_lon()
if ignore_distance_to_coast:
# Select centroids with lat < 61
coastal_idx = (np.abs(centroids.lat) < 61).nonzero()[0]
else:
# Select centroids which are inside INLAND_MAX_DIST_KM and lat < 61
if not centroids.dist_coast.size:
centroids.set_dist_coast()
coastal_idx = ((centroids.dist_coast < INLAND_MAX_DIST_KM * 1000)
& (np.abs(centroids.lat) < 61)).nonzero()[0]
# Restrict to coastal centroids within reach of any of the tracks
t_lon_min, t_lat_min, t_lon_max, t_lat_max = tracks.get_bounds(
deg_buffer=CENTR_NODE_MAX_DIST_DEG)
t_mid_lon = 0.5 * (t_lon_min + t_lon_max)
coastal_centroids = centroids.coord[coastal_idx]
u_coord.lon_normalize(coastal_centroids[:, 1], center=t_mid_lon)
coastal_idx = coastal_idx[((t_lon_min <= coastal_centroids[:, 1])
& (coastal_centroids[:, 1] <= t_lon_max)
& (t_lat_min <= coastal_centroids[:, 0])
& (coastal_centroids[:, 0] <= t_lat_max))]
LOGGER.info('Mapping %s tracks to %s coastal centroids.',
str(tracks.size), str(coastal_idx.size))
if self.pool:
chunksize = min(num_tracks // self.pool.ncpus, 1000)
tc_haz = self.pool.map(self._tc_from_track,
tracks.data,
itertools.repeat(centroids, num_tracks),
itertools.repeat(coastal_idx, num_tracks),
itertools.repeat(model, num_tracks),
itertools.repeat(store_windfields,
num_tracks),
itertools.repeat(metric, num_tracks),
chunksize=chunksize)
else:
last_perc = 0
tc_haz = []
for track in tracks.data:
perc = 100 * len(tc_haz) / len(tracks.data)
if perc - last_perc >= 10:
LOGGER.info("Progress: %d%%", perc)
last_perc = perc
self.append(
self._tc_from_track(track,
centroids,
coastal_idx,
model=model,
store_windfields=store_windfields,
metric=metric))
if last_perc < 100:
LOGGER.info("Progress: 100%")
LOGGER.debug('Compute frequency.')
self.frequency_from_tracks(tracks.data)
self.tag.description = description
def set_from_tracks(self, tracks, centroids=None, description='',
model='H08', ignore_distance_to_coast=False,
store_windfields=False, metric="equirect"):
"""Clear and fill with windfields from specified tracks.
Parameters
----------
tracks : TCTracks
Tracks of storm events.
centroids : Centroids, optional
Centroids where to model TC. Default: global centroids at 360 arc-seconds resolution.
description : str, optional
Description of the event set. Default: "".
model : str, optional
Model to compute gust. Currently only 'H08' is supported for the one implemented in
`_stat_holland` according to Greg Holland. Default: "H08".
ignore_distance_to_coast : boolean, optional
If True, centroids far from coast are not ignored. Default: False.
store_windfields : boolean, optional
If True, the Hazard object gets a list `windfields` of sparse matrices. For each track,
the full velocity vectors at each centroid and track position are stored in a sparse
matrix of shape (npositions, ncentroids * 2) that can be reshaped to a full ndarray
of shape (npositions, ncentroids, 2). Default: False.
metric : str, optional
Specify an approximation method to use for earth distances:
* "equirect": Distance according to sinusoidal projection. Fast, but inaccurate for
large distances and high latitudes.
* "geosphere": Exact spherical distance. Much more accurate at all distances, but slow.
Default: "equirect".
Raises
------
ValueError
"""
num_tracks = tracks.size
if centroids is None:
centroids = Centroids.from_base_grid(res_as=360, land=False)
if not centroids.coord.size:
centroids.set_meta_to_lat_lon()
if ignore_distance_to_coast:
# Select centroids with lat < 61
coastal_idx = (np.abs(centroids.lat) < 61).nonzero()[0]
else:
# Select centroids which are inside INLAND_MAX_DIST_KM and lat < 61
if not centroids.dist_coast.size:
centroids.set_dist_coast()
coastal_idx = ((centroids.dist_coast < INLAND_MAX_DIST_KM * 1000)
& (np.abs(centroids.lat) < 61)).nonzero()[0]
# Restrict to coastal centroids within reach of any of the tracks
t_lon_min, t_lat_min, t_lon_max, t_lat_max = tracks.get_bounds(
deg_buffer=CENTR_NODE_MAX_DIST_DEG)
t_mid_lon = 0.5 * (t_lon_min + t_lon_max)
coastal_centroids = centroids.coord[coastal_idx]
u_coord.lon_normalize(coastal_centroids[:, 1], center=t_mid_lon)
coastal_idx = coastal_idx[((t_lon_min <= coastal_centroids[:, 1])
& (coastal_centroids[:, 1] <= t_lon_max)
& (t_lat_min <= coastal_centroids[:, 0])
& (coastal_centroids[:, 0] <= t_lat_max))]
LOGGER.info('Mapping %s tracks to %s coastal centroids.', str(tracks.size),
str(coastal_idx.size))
if self.pool:
chunksize = min(num_tracks // self.pool.ncpus, 1000)
tc_haz = self.pool.map(
self._tc_from_track, tracks.data,
itertools.repeat(centroids, num_tracks),
itertools.repeat(coastal_idx, num_tracks),
itertools.repeat(model, num_tracks),
itertools.repeat(store_windfields, num_tracks),
itertools.repeat(metric, num_tracks),
chunksize=chunksize)
else:
last_perc = 0
tc_haz = []
for track in tracks.data:
perc = 100 * len(tc_haz) / len(tracks.data)
if perc - last_perc >= 10:
LOGGER.info("Progress: %d%%", perc)
last_perc = perc
tc_haz.append(
self._tc_from_track(track, centroids, coastal_idx,
model=model, store_windfields=store_windfields,
metric=metric))
if last_perc < 100:
LOGGER.info("Progress: 100%")
LOGGER.debug('Append events.')
self.concatenate(tc_haz)
LOGGER.debug('Compute frequency.')
self.frequency_from_tracks(tracks.data)
self.tag.description = description