def get_delay(grib_file, inps):
"""Get delay matrix using PyAPS for one acquisition
Inputs:
grib_file - strng, grib file path
atr - dict, including the following attributes:
dem_file - string, DEM file path
tropo_model - string, Weather re-analysis data source
delay_type - string, comb/dry/wet
ref_y/x - string, reference pixel row/col number
inc_angle - np.array, 0/1/2 D
Output:
pha - 2D np.array, absolute tropospheric phase delay relative to ref_y/x
"""
# initiate pyaps object
aps_obj = pa.PyAPS(grib_file,
grib=inps.tropo_model,
Del=inps.delay_type,
dem=inps.dem,
inc=inps.inc,
lat=inps.lat,
lon=inps.lon,
verb=verbose)
# estimate delay
pha = np.zeros((aps_obj.ny, aps_obj.nx), dtype=np.float32)
aps_obj.getdelay(pha)
# reverse the sign for consistency between different phase correction steps/methods
pha *= -1
return pha
def get_delay(grib_file, tropo_model, delay_type, dem, inc, lat, lon, mask=None, verbose=False):
"""Get delay matrix using PyAPS for one acquisition
Parameters: grib_file - str, grib file path
tropo_model - str, GAM model
delay_type - str, dry/wet/comb
dem/inc/lat/lon - 2D np.ndarray in float32 for DEM, incidence angle, latitude/longitude
verbose - bool, verbose message
Returns: pha - 2D np.ndarray in float32, single path tropospheric delay
temporally absolute, spatially referenced to ref_y/x
"""
if verbose:
print('GRIB FILE: {}'.format(grib_file))
# initiate pyaps object
aps_obj = pa.PyAPS(grib_file,
grib=tropo_model,
Del=delay_type,
dem=dem,
inc=inc,
lat=lat,
lon=lon,
mask=mask,
verb=verbose)
# estimate delay
pha = np.zeros((aps_obj.ny, aps_obj.nx), dtype=np.float32)
aps_obj.getdelay(pha)
# reverse the sign for consistency between different phase correction steps/methods
pha *= -1
return pha
dem = pa.utils.read_data(os.path.join(data_dir, 'hgt.rdr'))
inc = pa.utils.read_data(os.path.join(data_dir, 'los.rdr'), dname='inc')
lat = pa.utils.read_data(os.path.join(data_dir, 'lat.rdr'))
lon = pa.utils.read_data(os.path.join(data_dir, 'lon.rdr'))
# calculate
print('calculate tropospheric delay from GRB files...')
print('------------------------------------------------')
grb_file1 = os.path.join(data_dir,
'ERA5/ERA5_N30_N40_E120_E140_20101017_14.grb')
grb_file2 = os.path.join(data_dir,
'ERA5/ERA5_N30_N40_E120_E140_20110117_14.grb')
obj1 = pa.PyAPS(grb_file1,
dem=dem,
inc=inc,
lat=lat,
lon=lon,
grib='ERA5',
verb=True)
obj2 = pa.PyAPS(grb_file2,
dem=dem,
inc=inc,
lat=lat,
lon=lon,
grib='ERA5',
verb=True)
phs = obj2.getdelay() - obj1.getdelay()
# plot
date12 = '{}_{}'.format(grb_file1.split('_')[-2], grb_file2.split('_')[-2])
fig, ax = plt.subplots(figsize=[5, 7])
