def apparent_mb_from_any_mb(gdir, mb_model=None, mb_years=None):
"""Compute apparent mb from an arbitrary mass-balance profile.
This searches for a mass-balance residual to add to the mass-balance
profile so that the average specific MB is zero.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
mb_model : :py:class:`oggm.core.massbalance.MassBalanceModel`
the mass-balance model to use (superseedes mb_list)
mb_years : array
the array of years from which you want to average the MB for (for
mb_model only).
"""
# Do we have a calving glacier?
cmb = calving_mb(gdir)
# For each flowline compute the apparent MB
fls = gdir.read_pickle('inversion_flowlines')
def to_minimize(residual):
smb = mb_model.get_specific_mb(fls=fls, year=mb_years)
smb = np.mean(smb) + residual[0]
return (smb - cmb)**2
residual = optimization.minimize(to_minimize, [0.], bounds=((-1e5, 1e5), ))
residual = residual['x'][0]
# Reset flux
for fl in fls:
fl.flux = np.zeros(len(fl.surface_h))
# Flowlines in order to be sure
rho = cfg.PARAMS['ice_density']
for fl_id, fl in enumerate(fls):
mbz = 0
for yr in mb_years:
mbz += mb_model.get_annual_mb(fl.surface_h,
year=yr,
fls=fls,
fl_id=fl_id)
mbz = mbz / len(mb_years)
fl.set_apparent_mb(mbz * cfg.SEC_IN_YEAR * rho + residual)
# Check and write
aflux = fls[-1].flux[-1] * 1e-9 / rho * gdir.grid.dx**2
# If not marine and a bit far from zero, warning
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=0.01):
log.info('(%s) flux should be zero, but is: '
'%.4f km3 ice yr-1', gdir.rgi_id, aflux)
# If not marine and quite far from zero, error
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=1):
msg = ('({}) flux should be zero, but is: {:.4f} km3 ice yr-1'.format(
gdir.rgi_id, aflux))
raise MassBalanceCalibrationError(msg)
gdir.write_pickle(fls, 'inversion_flowlines')
def glacier_mu_candidates(gdir):
"""Computes the mu candidates, glacier wide.
For each 31 year-period centered on the year of interest, mu is is the
temperature sensitivity necessary for the glacier with its current shape
to be in equilibrium with its climate.
This task is just for documentation and testing! It is not used in
production anymore.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
"""
warnings.warn(
'The task `glacier_mu_candidates` is deprecated. It should '
'only be used for testing.', DeprecationWarning)
mu_hp = int(cfg.PARAMS['mu_star_halfperiod'])
# Only get the years were we consider looking for tstar
y0, y1 = cfg.PARAMS['tstar_search_window']
ci = gdir.read_json('climate_info')
y0 = y0 or ci['baseline_hydro_yr_0']
y1 = y1 or ci['baseline_hydro_yr_1']
years, temp_yr, prcp_yr = mb_yearly_climate_on_glacier(gdir,
year_range=[y0, y1])
# Compute mu for each 31-yr climatological period
ny = len(years)
mu_yr_clim = np.zeros(ny) * np.NaN
for i, y in enumerate(years):
# Ignore begin and end
if ((i - mu_hp) < 0) or ((i + mu_hp) >= ny):
continue
t_avg = np.mean(temp_yr[i - mu_hp:i + mu_hp + 1])
if t_avg > 1e-3: # if too cold no melt possible
prcp_ts = prcp_yr[i - mu_hp:i + mu_hp + 1]
mu_yr_clim[i] = np.mean(prcp_ts) / t_avg
# Check that we found a least one mustar
if np.sum(np.isfinite(mu_yr_clim)) < 1:
raise MassBalanceCalibrationError(
'({}) no mustar candidates found.'.format(gdir.rgi_id))
# Write
return pd.Series(data=mu_yr_clim, index=years)
def process_cru_data(gdir, tmp_file=None, pre_file=None, y0=None, y1=None,
output_filesuffix=None):
"""Processes and writes the CRU baseline climate data for this glacier.
Interpolates the CRU TS data to the high-resolution CL2 climatologies
(provided with OGGM) and writes everything to a NetCDF file.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
tmp_file : str
path to the CRU temperature file (defaults to the current OGGM chosen
CRU version)
pre_file : str
path to the CRU precip file (defaults to the current OGGM chosen
CRU version)
y0 : int
the starting year of the timeseries to write. The default is to take
the entire time period available in the file, but with this kwarg
you can shorten it (to save space or to crop bad data)
y1 : int
the starting year of the timeseries to write. The default is to take
the entire time period available in the file, but with this kwarg
you can shorten it (to save space or to crop bad data)
output_filesuffix : str
this add a suffix to the output file (useful to avoid overwriting
previous experiments)
"""
if cfg.PATHS.get('climate_file', None):
warnings.warn("You seem to have set a custom climate file for this "
"run, but are using the default CRU climate "
"file instead.")
if cfg.PARAMS['baseline_climate'] != 'CRU':
raise InvalidParamsError("cfg.PARAMS['baseline_climate'] should be "
"set to CRU")
# read the climatology
ncclim = salem.GeoNetcdf(get_cru_cl_file())
# and the TS data
if tmp_file is None:
tmp_file = get_cru_file('tmp')
if pre_file is None:
pre_file = get_cru_file('pre')
nc_ts_tmp = salem.GeoNetcdf(tmp_file, monthbegin=True)
nc_ts_pre = salem.GeoNetcdf(pre_file, monthbegin=True)
# set temporal subset for the ts data (hydro years)
sm = cfg.PARAMS['hydro_month_' + gdir.hemisphere]
em = sm - 1 if (sm > 1) else 12
yrs = nc_ts_pre.time.year
y0 = yrs[0] if y0 is None else y0
y1 = yrs[-1] if y1 is None else y1
nc_ts_tmp.set_period(t0='{}-{:02d}-01'.format(y0, sm),
t1='{}-{:02d}-01'.format(y1, em))
nc_ts_pre.set_period(t0='{}-{:02d}-01'.format(y0, sm),
t1='{}-{:02d}-01'.format(y1, em))
time = nc_ts_pre.time
ny, r = divmod(len(time), 12)
assert r == 0
lon = gdir.cenlon
lat = gdir.cenlat
# This is guaranteed to work because I prepared the file (I hope)
ncclim.set_subset(corners=((lon, lat), (lon, lat)), margin=1)
# get climatology data
loc_hgt = ncclim.get_vardata('elev')
loc_tmp = ncclim.get_vardata('temp')
loc_pre = ncclim.get_vardata('prcp')
loc_lon = ncclim.get_vardata('lon')
loc_lat = ncclim.get_vardata('lat')
# see if the center is ok
if not np.isfinite(loc_hgt[1, 1]):
# take another candidate where finite
isok = np.isfinite(loc_hgt)
# wait: some areas are entirely NaNs, make the subset larger
_margin = 1
while not np.any(isok):
_margin += 1
ncclim.set_subset(corners=((lon, lat), (lon, lat)), margin=_margin)
loc_hgt = ncclim.get_vardata('elev')
isok = np.isfinite(loc_hgt)
if _margin > 1:
log.debug('(%s) I had to look up for far climate pixels: %s',
gdir.rgi_id, _margin)
# Take the first candidate (doesn't matter which)
lon, lat = ncclim.grid.ll_coordinates
lon = lon[isok][0]
lat = lat[isok][0]
# Resubset
ncclim.set_subset()
ncclim.set_subset(corners=((lon, lat), (lon, lat)), margin=1)
loc_hgt = ncclim.get_vardata('elev')
loc_tmp = ncclim.get_vardata('temp')
loc_pre = ncclim.get_vardata('prcp')
loc_lon = ncclim.get_vardata('lon')
loc_lat = ncclim.get_vardata('lat')
assert np.isfinite(loc_hgt[1, 1])
isok = np.isfinite(loc_hgt)
hgt_f = loc_hgt[isok].flatten()
assert len(hgt_f) > 0.
# Should we compute the gradient?
use_grad = cfg.PARAMS['temp_use_local_gradient']
ts_grad = None
if use_grad and len(hgt_f) >= 5:
ts_grad = np.zeros(12) * np.NaN
for i in range(12):
loc_tmp_mth = loc_tmp[i, ...][isok].flatten()
slope, _, _, p_val, _ = stats.linregress(hgt_f, loc_tmp_mth)
ts_grad[i] = slope if (p_val < 0.01) else np.NaN
# convert to a timeseries and hydrological years
ts_grad = ts_grad.tolist()
ts_grad = ts_grad[em:] + ts_grad[0:em]
ts_grad = np.asarray(ts_grad * ny)
# maybe this will throw out of bounds warnings
nc_ts_tmp.set_subset(corners=((lon, lat), (lon, lat)), margin=1)
nc_ts_pre.set_subset(corners=((lon, lat), (lon, lat)), margin=1)
# compute monthly anomalies
# of temp
ts_tmp = nc_ts_tmp.get_vardata('tmp', as_xarray=True)
ts_tmp_avg = ts_tmp.sel(time=slice('1961-01-01', '1990-12-01'))
ts_tmp_avg = ts_tmp_avg.groupby('time.month').mean(dim='time')
ts_tmp = ts_tmp.groupby('time.month') - ts_tmp_avg
# of precip
ts_pre = nc_ts_pre.get_vardata('pre', as_xarray=True)
ts_pre_avg = ts_pre.sel(time=slice('1961-01-01', '1990-12-01'))
ts_pre_avg = ts_pre_avg.groupby('time.month').mean(dim='time')
ts_pre_ano = ts_pre.groupby('time.month') - ts_pre_avg
# scaled anomalies is the default. Standard anomalies above
# are used later for where ts_pre_avg == 0
ts_pre = ts_pre.groupby('time.month') / ts_pre_avg
# interpolate to HR grid
if np.any(~np.isfinite(ts_tmp[:, 1, 1])):
# Extreme case, middle pix is not valid
# take any valid pix from the 3*3 (and hope there's one)
found_it = False
for idi in range(2):
for idj in range(2):
if np.all(np.isfinite(ts_tmp[:, idj, idi])):
ts_tmp[:, 1, 1] = ts_tmp[:, idj, idi]
ts_pre[:, 1, 1] = ts_pre[:, idj, idi]
ts_pre_ano[:, 1, 1] = ts_pre_ano[:, idj, idi]
found_it = True
if not found_it:
msg = '({}) there is no climate data'.format(gdir.rgi_id)
raise MassBalanceCalibrationError(msg)
elif np.any(~np.isfinite(ts_tmp)):
# maybe the side is nan, but we can do nearest
ts_tmp = ncclim.grid.map_gridded_data(ts_tmp.values, nc_ts_tmp.grid,
interp='nearest')
ts_pre = ncclim.grid.map_gridded_data(ts_pre.values, nc_ts_pre.grid,
interp='nearest')
ts_pre_ano = ncclim.grid.map_gridded_data(ts_pre_ano.values,
nc_ts_pre.grid,
interp='nearest')
else:
# We can do bilinear
ts_tmp = ncclim.grid.map_gridded_data(ts_tmp.values, nc_ts_tmp.grid,
interp='linear')
ts_pre = ncclim.grid.map_gridded_data(ts_pre.values, nc_ts_pre.grid,
interp='linear')
ts_pre_ano = ncclim.grid.map_gridded_data(ts_pre_ano.values,
nc_ts_pre.grid,
interp='linear')
# take the center pixel and add it to the CRU CL clim
# for temp
loc_tmp = xr.DataArray(loc_tmp[:, 1, 1], dims=['month'],
coords={'month': ts_tmp_avg.month})
ts_tmp = xr.DataArray(ts_tmp[:, 1, 1], dims=['time'],
coords={'time': time})
ts_tmp = ts_tmp.groupby('time.month') + loc_tmp
# for prcp
loc_pre = xr.DataArray(loc_pre[:, 1, 1], dims=['month'],
coords={'month': ts_pre_avg.month})
ts_pre = xr.DataArray(ts_pre[:, 1, 1], dims=['time'],
coords={'time': time})
ts_pre_ano = xr.DataArray(ts_pre_ano[:, 1, 1], dims=['time'],
coords={'time': time})
# scaled anomalies
ts_pre = ts_pre.groupby('time.month') * loc_pre
# standard anomalies
ts_pre_ano = ts_pre_ano.groupby('time.month') + loc_pre
# Correct infinite values with standard anomalies
ts_pre.values = np.where(np.isfinite(ts_pre.values),
ts_pre.values,
ts_pre_ano.values)
# The last step might create negative values (unlikely). Clip them
ts_pre.values = utils.clip_min(ts_pre.values, 0)
# done
loc_hgt = loc_hgt[1, 1]
loc_lon = loc_lon[1]
loc_lat = loc_lat[1]
assert np.isfinite(loc_hgt)
assert np.all(np.isfinite(ts_pre.values))
assert np.all(np.isfinite(ts_tmp.values))
gdir.write_monthly_climate_file(time, ts_pre.values, ts_tmp.values,
loc_hgt, loc_lon, loc_lat,
filesuffix=output_filesuffix,
gradient=ts_grad,
source=nc_ts_tmp._nc.title[:10])
ncclim._nc.close()
nc_ts_tmp._nc.close()
nc_ts_pre._nc.close()
def apparent_mb_from_linear_mb(gdir, mb_gradient=3., ela_h=None):
"""Compute apparent mb from a linear mass-balance assumption (for testing).
This is for testing currently, but could be used as alternative method
for the inversion quite easily.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
"""
# Do we have a calving glacier?
cmb = calving_mb(gdir)
# Get the height and widths along the fls
h, w = gdir.get_inversion_flowline_hw()
# Now find the ELA till the integrated mb is zero
from oggm.core.massbalance import LinearMassBalance
def to_minimize(ela_h):
mbmod = LinearMassBalance(ela_h[0], grad=mb_gradient)
smb = mbmod.get_specific_mb(heights=h, widths=w)
return (smb - cmb)**2
if ela_h is None:
ela_h = optimization.minimize(to_minimize, [0.], bounds=((0, 10000), ))
ela_h = ela_h['x'][0]
mbmod = LinearMassBalance(ela_h, grad=mb_gradient)
# For each flowline compute the apparent MB
fls = gdir.read_pickle('inversion_flowlines')
# Reset flux
for fl in fls:
fl.flux = np.zeros(len(fl.surface_h))
# Flowlines in order to be sure
rho = cfg.PARAMS['ice_density']
for fl in fls:
mbz = mbmod.get_annual_mb(fl.surface_h) * cfg.SEC_IN_YEAR * rho
fl.set_apparent_mb(mbz)
# Check and write
aflux = fls[-1].flux[-1] * 1e-9 / rho * gdir.grid.dx**2
# If not marine and a bit far from zero, warning
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=0.01):
log.info('(%s) flux should be zero, but is: '
'%.4f km3 ice yr-1', gdir.rgi_id, aflux)
# If not marine and quite far from zero, error
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=1):
msg = ('({}) flux should be zero, but is: {:.4f} km3 ice yr-1'.format(
gdir.rgi_id, aflux))
raise MassBalanceCalibrationError(msg)
gdir.write_pickle(fls, 'inversion_flowlines')
gdir.write_pickle({
'ela_h': ela_h,
'grad': mb_gradient
}, 'linear_mb_params')
def mu_star_calibration(gdir):
"""Compute the flowlines' mu* and the associated apparent mass-balance.
If low lying tributaries have a non-physically consistent Mass-balance
this function will either filter them out or calibrate each flowline with a
specific mu*. The latter is default and recommended.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
"""
# Interpolated data
df = gdir.read_json('local_mustar')
t_star = df['t_star']
bias = df['bias']
# For each flowline compute the apparent MB
fls = gdir.read_pickle('inversion_flowlines')
# If someone calls the task a second time we need to reset this
for fl in fls:
fl.mu_star_is_valid = False
force_mu = 0 if df['mu_star_glacierwide'] == 0 else None
# Let's go
_recursive_mu_star_calibration(gdir, fls, t_star, force_mu=force_mu)
# If the user wants to filter the bad ones we remove them and start all
# over again until all tributaries are physically consistent with one mu
# This should only work if cfg.PARAMS['correct_for_neg_flux'] == False
do_filter = [fl.flux_needs_correction for fl in fls]
if cfg.PARAMS['filter_for_neg_flux'] and np.any(do_filter):
assert not do_filter[-1] # This should not happen
# Keep only the good lines
# TODO: this should use centerline.line_inflows for more efficiency!
heads = [fl.orig_head for fl in fls if not fl.flux_needs_correction]
centerlines.compute_centerlines(gdir, heads=heads, reset=True)
centerlines.initialize_flowlines(gdir, reset=True)
if gdir.has_file('downstream_line'):
centerlines.compute_downstream_line(gdir, reset=True)
centerlines.compute_downstream_bedshape(gdir, reset=True)
centerlines.catchment_area(gdir, reset=True)
centerlines.catchment_intersections(gdir, reset=True)
centerlines.catchment_width_geom(gdir, reset=True)
centerlines.catchment_width_correction(gdir, reset=True)
local_t_star(gdir, tstar=t_star, bias=bias, reset=True)
# Ok, re-call ourselves
return mu_star_calibration(gdir, reset=True)
# Check and write
rho = cfg.PARAMS['ice_density']
aflux = fls[-1].flux[-1] * 1e-9 / rho * gdir.grid.dx**2
# If not marine and a bit far from zero, warning
cmb = calving_mb(gdir)
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=0.01):
log.info('(%s) flux should be zero, but is: '
'%.4f km3 ice yr-1', gdir.rgi_id, aflux)
# If not marine and quite far from zero, error
if cmb == 0 and not np.allclose(fls[-1].flux[-1], 0., atol=1):
msg = ('({}) flux should be zero, but is: {:.4f} km3 ice yr-1'.format(
gdir.rgi_id, aflux))
raise MassBalanceCalibrationError(msg)
gdir.write_pickle(fls, 'inversion_flowlines')
# Store diagnostics
mus = []
weights = []
for fl in fls:
mus.append(fl.mu_star)
weights.append(np.sum(fl.widths))
df['mu_star_per_flowline'] = mus
df['mu_star_flowline_avg'] = np.average(mus, weights=weights)
all_same = np.allclose(mus, mus[0], atol=1e-3)
df['mu_star_allsame'] = all_same
if all_same:
if not np.allclose(df['mu_star_flowline_avg'],
df['mu_star_glacierwide'],
atol=1e-3):
raise MassBalanceCalibrationError('Unexpected difference between '
'glacier wide mu* and the '
'flowlines mu*.')
# Write
gdir.write_json(df, 'local_mustar')
def _recursive_mu_star_calibration(gdir,
fls,
t_star,
first_call=True,
force_mu=None):
# Do we have a calving glacier? This is only for the first call!
# The calving mass-balance is distributed over the valid tributaries of the
# main line, i.e. bad tributaries are not considered for calving
cmb = calving_mb(gdir) if first_call else 0.
# Climate period
mu_hp = int(cfg.PARAMS['mu_star_halfperiod'])
yr_range = [t_star - mu_hp, t_star + mu_hp]
# Get the corresponding mu
heights = np.array([])
widths = np.array([])
for fl in fls:
heights = np.append(heights, fl.surface_h)
widths = np.append(widths, fl.widths)
_, temp, prcp = mb_yearly_climate_on_height(gdir,
heights,
year_range=yr_range,
flatten=False)
if force_mu is None:
try:
mu_star = optimization.brentq(_mu_star_per_minimization,
cfg.PARAMS['min_mu_star'],
cfg.PARAMS['max_mu_star'],
args=(fls, cmb, temp, prcp, widths),
xtol=1e-5)
except ValueError:
# This happens in very rare cases
_mu_lim = _mu_star_per_minimization(cfg.PARAMS['min_mu_star'], fls,
cmb, temp, prcp, widths)
if _mu_lim < 0 and np.allclose(_mu_lim, 0):
mu_star = 0.
else:
raise MassBalanceCalibrationError('{} mu* out of specified '
'bounds.'.format(
gdir.rgi_id))
if not np.isfinite(mu_star):
raise MassBalanceCalibrationError('{} '.format(gdir.rgi_id) +
'has a non finite mu.')
else:
mu_star = force_mu
# Reset flux
for fl in fls:
fl.flux = np.zeros(len(fl.surface_h))
# Flowlines in order to be sure - start with first guess mu*
for fl in fls:
y, t, p = mb_yearly_climate_on_height(gdir,
fl.surface_h,
year_range=yr_range,
flatten=False)
mu = fl.mu_star if fl.mu_star_is_valid else mu_star
fl.set_apparent_mb(np.mean(p, axis=1) - mu * np.mean(t, axis=1),
mu_star=mu)
# Sometimes, low lying tributaries have a non-physically consistent
# Mass-balance. These tributaries wouldn't exist with a single
# glacier-wide mu*, and therefore need a specific calibration.
# All other mus may be affected
if cfg.PARAMS['correct_for_neg_flux'] and (len(fls) > 1):
if np.any([fl.flux_needs_correction for fl in fls]):
# We start with the highest Strahler number that needs correction
not_ok = np.array([fl.flux_needs_correction for fl in fls])
fl = np.array(fls)[not_ok][-1]
# And we take all its tributaries
inflows = centerlines.line_inflows(fl)
# We find a new mu for these in a recursive call
# TODO: this is where a flux kwarg can passed to tributaries
_recursive_mu_star_calibration(gdir,
inflows,
t_star,
first_call=False)
# At this stage we should be ok
assert np.all([~fl.flux_needs_correction for fl in inflows])
for fl in inflows:
fl.mu_star_is_valid = True
# After the above are OK we have to recalibrate all below
_recursive_mu_star_calibration(gdir,
fls,
t_star,
first_call=first_call)
# At this stage we are good
for fl in fls:
fl.mu_star_is_valid = True
def local_t_star(gdir, *, ref_df=None, tstar=None, bias=None):
"""Compute the local t* and associated glacier-wide mu*.
If ``tstar`` and ``bias`` are not provided, they will be interpolated from
the reference t* list.
Note: the glacier wide mu* is here just for indication. It might be
different from the flowlines' mu* in some cases.
Parameters
----------
gdir : :py:class:`oggm.GlacierDirectory`
the glacier directory to process
ref_df : :py:class:`pandas.DataFrame`, optional
replace the default calibration list with your own.
tstar: int, optional
the year where the glacier should be equilibrium
bias: float, optional
the associated reference bias
"""
# Relevant mb params
params = [
'temp_default_gradient', 'temp_all_solid', 'temp_all_liq', 'temp_melt',
'prcp_scaling_factor'
]
if tstar is None or bias is None:
# Do our own interpolation
if ref_df is None:
if not cfg.PARAMS['run_mb_calibration']:
# Make some checks and use the default one
climate_info = gdir.read_json('climate_info')
source = climate_info['baseline_climate_source']
ok_source = ['CRU TS4.01', 'CRU TS3.23', 'HISTALP']
if not np.any(s in source.upper() for s in ok_source):
msg = ('If you are using a custom climate file you should '
'run your own MB calibration.')
raise MassBalanceCalibrationError(msg)
v = gdir.rgi_version[0] # major version relevant
# Check that the params are fine
s = 'cru4' if 'CRU' in source else 'histalp'
vn = 'oggm_ref_tstars_rgi{}_{}_calib_params'.format(v, s)
for k in params:
if cfg.PARAMS[k] != cfg.PARAMS[vn][k]:
msg = ('The reference t* you are trying to use was '
'calibrated with different MB parameters. You '
'might have to run the calibration manually.')
raise MassBalanceCalibrationError(msg)
ref_df = cfg.PARAMS['oggm_ref_tstars_rgi{}_{}'.format(v, s)]
else:
# Use the the local calibration
fp = os.path.join(cfg.PATHS['working_dir'], 'ref_tstars.csv')
ref_df = pd.read_csv(fp)
# Compute the distance to each glacier
distances = utils.haversine(gdir.cenlon, gdir.cenlat, ref_df.lon,
ref_df.lat)
# Take the 10 closest
aso = np.argsort(distances)[0:9]
amin = ref_df.iloc[aso]
distances = distances[aso]**2
# If really close no need to divide, else weighted average
if distances.iloc[0] <= 0.1:
tstar = amin.tstar.iloc[0]
bias = amin.bias.iloc[0]
else:
tstar = int(np.average(amin.tstar, weights=1. / distances))
bias = np.average(amin.bias, weights=1. / distances)
# Add the climate related params to the GlacierDir to make sure
# other tools cannot fool around without re-calibration
out = gdir.read_json('climate_info')
out['mb_calib_params'] = {k: cfg.PARAMS[k] for k in params}
gdir.write_json(out, 'climate_info')
# We compute the overall mu* here but this is mostly for testing
# Climate period
mu_hp = int(cfg.PARAMS['mu_star_halfperiod'])
yr = [tstar - mu_hp, tstar + mu_hp]
# Do we have a calving glacier?
cmb = calving_mb(gdir)
log.info('(%s) local mu* computation for t*=%d', gdir.rgi_id, tstar)
# Get the corresponding mu
years, temp_yr, prcp_yr = mb_yearly_climate_on_glacier(gdir, year_range=yr)
assert len(years) == (2 * mu_hp + 1)
# mustar is taking calving into account (units of specific MB)
mustar = (np.mean(prcp_yr) - cmb) / np.mean(temp_yr)
if not np.isfinite(mustar):
raise MassBalanceCalibrationError('{} has a non finite '
'mu'.format(gdir.rgi_id))
# Clip it?
if cfg.PARAMS['clip_mu_star']:
mustar = utils.clip_min(mustar, 0)
# If mu out of bounds, raise
if not (cfg.PARAMS['min_mu_star'] <= mustar <= cfg.PARAMS['max_mu_star']):
raise MassBalanceCalibrationError('mu* out of specified bounds: '
'{:.2f}'.format(mustar))
# Scalars in a small dict for later
df = dict()
df['rgi_id'] = gdir.rgi_id
df['t_star'] = int(tstar)
df['bias'] = bias
df['mu_star_glacierwide'] = mustar
gdir.write_json(df, 'local_mustar')
def t_star_from_refmb(gdir, mbdf=None, glacierwide=None):
"""Computes the ref t* for the glacier, given a series of MB measurements.
Parameters
----------
gdir : oggm.GlacierDirectory
mbdf: a pd.Series containing the observed MB data indexed by year
if None, read automatically from the reference data
Returns
-------
A dict: {t_star:[], bias:[]}
"""
from oggm.core.massbalance import MultipleFlowlineMassBalance
if glacierwide is None:
glacierwide = cfg.PARAMS['tstar_search_glacierwide']
# Be sure we have no marine terminating glacier
assert not gdir.is_tidewater
# Reference time series
if mbdf is None:
mbdf = gdir.get_ref_mb_data()['ANNUAL_BALANCE']
# which years to look at
ref_years = mbdf.index.values
# Average oberved mass-balance
ref_mb = np.mean(mbdf)
# Compute one mu candidate per year and the associated statistics
# Only get the years were we consider looking for tstar
y0, y1 = cfg.PARAMS['tstar_search_window']
ci = gdir.read_json('climate_info')
y0 = y0 or ci['baseline_hydro_yr_0']
y1 = y1 or ci['baseline_hydro_yr_1']
years = np.arange(y0, y1 + 1)
ny = len(years)
mu_hp = int(cfg.PARAMS['mu_star_halfperiod'])
mb_per_mu = pd.Series(index=years)
if glacierwide:
# The old (but fast) method to find t*
_, temp, prcp = mb_yearly_climate_on_glacier(gdir, year_range=[y0, y1])
# which years to look at
selind = np.searchsorted(years, mbdf.index)
sel_temp = temp[selind]
sel_prcp = prcp[selind]
sel_temp = np.mean(sel_temp)
sel_prcp = np.mean(sel_prcp)
for i, y in enumerate(years):
# Ignore begin and end
if ((i - mu_hp) < 0) or ((i + mu_hp) >= ny):
continue
# Compute the mu candidate
t_avg = np.mean(temp[i - mu_hp:i + mu_hp + 1])
if t_avg < 1e-3: # if too cold no melt possible
continue
mu = np.mean(prcp[i - mu_hp:i + mu_hp + 1]) / t_avg
# Apply it
mb_per_mu[y] = np.mean(sel_prcp - mu * sel_temp)
else:
# The new (but slow) method to find t*
# Compute mu for each 31-yr climatological period
fls = gdir.read_pickle('inversion_flowlines')
for i, y in enumerate(years):
# Ignore begin and end
if ((i - mu_hp) < 0) or ((i + mu_hp) >= ny):
continue
# Calibrate the mu for this year
for fl in fls:
fl.mu_star_is_valid = False
try:
# TODO: this is slow and can be highly optimised
# it reads the same data over and over again
_recursive_mu_star_calibration(gdir, fls, y, first_call=True)
# Compute the MB with it
mb_mod = MultipleFlowlineMassBalance(gdir,
fls,
bias=0,
check_calib_params=False)
mb_ts = mb_mod.get_specific_mb(fls=fls, year=ref_years)
mb_per_mu[y] = np.mean(mb_ts)
except MassBalanceCalibrationError:
pass
# Diff to reference
diff = (mb_per_mu - ref_mb).dropna()
if len(diff) == 0:
raise MassBalanceCalibrationError('No single valid mu candidate for '
'this glacier!')
# Here we used to keep all possible mu* in order to later select
# them based on some distance search algorithms.
# (revision 81bc0923eab6301306184d26462f932b72b84117)
#
# As of Jul 2018, we will now stop this non-sense:
# out of all mu*, let's just pick the one with the smallest bias.
# It doesn't make much sense, but the same is true for other methods
# as well -> this is how Ben used to do it, and he is clever
# Another way would be to pick the closest to today or something
amin = np.abs(diff).idxmin()
# Write
d = gdir.read_json('climate_info')
d['t_star'] = amin
d['bias'] = diff[amin]
gdir.write_json(d, 'climate_info')
return {
't_star': amin,
'bias': diff[amin],
'avg_mb_per_mu': mb_per_mu,
'avg_ref_mb': ref_mb
}
def mb_climate_on_height(gdir, heights, *, time_range=None, year_range=None):
"""Mass-balance climate of the glacier at a specific height
Reads the glacier's monthly climate data file and computes the
temperature "energies" (temp above 0) and solid precipitation at the
required height.
All MB parameters are considered here! (i.e. melt temp, precip scaling
factor, etc.)
Parameters
----------
gdir : GlacierDirectory
the glacier directory
heights: ndarray
a 1D array of the heights (in meter) where you want the data
time_range : [datetime, datetime], optional
default is to read all data but with this you
can provide a [t0, t1] bounds (inclusive).
year_range : [int, int], optional
Provide a [y0, y1] year range to get the data for specific
(hydrological) years only. Easier to use than the time bounds above.
Returns
-------
(time, tempformelt, prcpsol)::
- time: array of shape (nt,)
- tempformelt: array of shape (len(heights), nt)
- prcpsol: array of shape (len(heights), nt)
"""
if year_range is not None:
sm = cfg.PARAMS['hydro_month_' + gdir.hemisphere]
em = sm - 1 if (sm > 1) else 12
t0 = datetime.datetime(year_range[0] - 1, sm, 1)
t1 = datetime.datetime(year_range[1], em, 1)
return mb_climate_on_height(gdir, heights, time_range=[t0, t1])
# Parameters
temp_all_solid = cfg.PARAMS['temp_all_solid']
temp_all_liq = cfg.PARAMS['temp_all_liq']
temp_melt = cfg.PARAMS['temp_melt']
prcp_fac = cfg.PARAMS['prcp_scaling_factor']
default_grad = cfg.PARAMS['temp_default_gradient']
g_minmax = cfg.PARAMS['temp_local_gradient_bounds']
# Read file
igrad = None
with utils.ncDataset(gdir.get_filepath('climate_historical')) as nc:
# time
time = nc.variables['time']
time = netCDF4.num2date(time[:], time.units)
if time_range is not None:
p0 = np.where(time == time_range[0])[0]
try:
p0 = p0[0]
except IndexError:
raise MassBalanceCalibrationError('time_range[0] not found in '
'file')
p1 = np.where(time == time_range[1])[0]
try:
p1 = p1[0]
except IndexError:
raise MassBalanceCalibrationError('time_range[1] not found in '
'file')
else:
p0 = 0
p1 = len(time) - 1
time = time[p0:p1 + 1]
# Read timeseries
itemp = nc.variables['temp'][p0:p1 + 1]
iprcp = nc.variables['prcp'][p0:p1 + 1]
if 'gradient' in nc.variables:
igrad = nc.variables['gradient'][p0:p1 + 1]
# Security for stuff that can happen with local gradients
igrad = np.where(~np.isfinite(igrad), default_grad, igrad)
igrad = utils.clip_array(igrad, g_minmax[0], g_minmax[1])
ref_hgt = nc.ref_hgt
# Default gradient?
if igrad is None:
igrad = itemp * 0 + default_grad
# Correct precipitation
iprcp *= prcp_fac
# For each height pixel:
# Compute temp and tempformelt (temperature above melting threshold)
npix = len(heights)
grad_temp = np.atleast_2d(igrad).repeat(npix, 0)
grad_temp *= (heights.repeat(len(time)).reshape(grad_temp.shape) - ref_hgt)
temp2d = np.atleast_2d(itemp).repeat(npix, 0) + grad_temp
temp2dformelt = temp2d - temp_melt
temp2dformelt = utils.clip_min(temp2dformelt, 0)
# Compute solid precipitation from total precipitation
prcpsol = np.atleast_2d(iprcp).repeat(npix, 0)
fac = 1 - (temp2d - temp_all_solid) / (temp_all_liq - temp_all_solid)
fac = utils.clip_array(fac, 0, 1)
prcpsol = prcpsol * fac
return time, temp2dformelt, prcpsol