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DOC: Addition of references for rain rate methods. #1043

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DOC: Addition of references for rain rate methods. #1043

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200 changes: 111 additions & 89 deletions pyart/retrieve/qpe.py
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,15 @@ def est_rain_rate_zpoly(radar, refl_field=None, rr_field=None):
rain : dict
Field dictionary containing the rainfall rate.

References
----------
Doelling et al. Systematic variations of Z–R-relationships from drop size
distributions measured in northern Germany during seven years. 1998. Atmos.
Ocean. Technol, 21, 1545-1556.

Joss et al. Operational Use of Radar for Precipitation Measurements
in Switzerland. 1998. Vdf Hochschulverlag AG ETH Zurich: 134.

"""
# parse the field parameters
if refl_field is None:
Expand Down Expand Up @@ -74,6 +83,11 @@ def est_rain_rate_z(radar, alpha=0.0376, beta=0.6112, refl_field=None,
rain : dict
Field dictionary containing the rainfall rate.

Reference
---------
Fabry, Frédéric. Radar Meterology. 2015. Ch 9. pg 148-165.
https://doi.org/10.1017/CBO9781107707405

"""
# parse the field parameters
if refl_field is None:
Expand Down Expand Up @@ -114,6 +128,14 @@ def est_rain_rate_kdp(radar, alpha=None, beta=None, kdp_field=None,
rain : dict
Field dictionary containing the rainfall rate.

Reference
---------
Figueras et al. Long-term monitoring of French polarimetric radar data
quality and evaluation of several polarimetric quantitative precipitation
estimators in ideal conditions for operational implementation at C-band.
Quarterly Journal of the Royal Meteorological Society. 2012.
https://doi.org/10.1002/qj.1934

"""
# select the coefficients as alpha function of frequency band
if alpha is None or beta is None:
Expand Down Expand Up @@ -209,7 +231,7 @@ def est_rain_rate_a(radar, alpha=None, beta=None, a_field=None,

def est_rain_rate_zkdp(radar, alphaz=0.0376, betaz=0.6112, alphakdp=None,
betakdp=None, refl_field=None, kdp_field=None,
rr_field=None, master_field=None, thresh=None,
rr_field=None, main_field=None, thresh=None,
thresh_max=True):
"""
Estimates rainfall rate from a blending of power law r-kdp and r-z
Expand All @@ -231,19 +253,19 @@ def est_rain_rate_zkdp(radar, alphaz=0.0376, betaz=0.6112, alphakdp=None,
Name of the specific differential phase field to use.
rr_field : str, optional
Name of the rainfall rate field.
master_field : str, optional
Name of the field that is going to act as master. Has to be
main_field : str, optional
Name of the field that is going to act as main. Has to be
either refl_field or kdp_field. Default is refl_field.
thresh : float, optional
Value of the threshold that determines when to use the slave
Value of the threshold that determines when to use the secondary
field.
thresh_max : Bool, optional
If true the master field is used up to the thresh value maximum.
Otherwise the master field is not used below thresh value.
If true the main field is used up to the thresh value maximum.
Otherwise the main field is not used below thresh value.

Returns
-------
rain_master : dict
rain_main : dict
Field dictionary containing the rainfall rate.

"""
Expand All @@ -262,42 +284,42 @@ def est_rain_rate_zkdp(radar, alphaz=0.0376, betaz=0.6112, alphakdp=None,
radar, alpha=alphakdp, beta=betakdp, kdp_field=kdp_field,
rr_field=rr_field)

if master_field == refl_field:
slave_field = kdp_field
rain_master = rain_z
rain_slave = rain_kdp
elif master_field == kdp_field:
slave_field = refl_field
rain_master = rain_kdp
rain_slave = rain_z
elif master_field is None:
master_field = refl_field
slave_field = kdp_field
rain_master = rain_z
rain_slave = rain_kdp
if main_field == refl_field:
secondary_field = kdp_field
rain_main = rain_z
rain_secondary = rain_kdp
elif main_field == kdp_field:
secondary_field = refl_field
rain_main = rain_kdp
rain_secondary = rain_z
elif main_field is None:
main_field = refl_field
secondary_field = kdp_field
rain_main = rain_z
rain_secondary = rain_kdp
else:
master_field = refl_field
slave_field = kdp_field
rain_master = rain_z
rain_slave = rain_kdp
main_field = refl_field
secondary_field = kdp_field
rain_main = rain_z
rain_secondary = rain_kdp
thresh = 40.
thresh_max = True
warn('Unknown master field. Using ' + refl_field
warn('Unknown main field. Using ' + refl_field
+ ' with threshold ' + str(thresh))

if thresh_max:
is_slave = rain_master['data'] > thresh
is_secondary = rain_main['data'] > thresh
else:
is_slave = rain_master['data'] < thresh
rain_master['data'][is_slave] = (
rain_slave['data'][is_slave])
is_secondary = rain_main['data'] < thresh
rain_main['data'][is_secondary] = (
rain_secondary['data'][is_secondary])

return rain_master
return rain_main


def est_rain_rate_za(radar, alphaz=0.0376, betaz=0.6112, alphaa=None,
betaa=None, refl_field=None, a_field=None, rr_field=None,
master_field=None, thresh=None, thresh_max=False):
main_field=None, thresh=None, thresh_max=False):
"""
Estimates rainfall rate from a blending of power law r-alpha and r-z
relations.
Expand All @@ -317,19 +339,19 @@ def est_rain_rate_za(radar, alphaz=0.0376, betaz=0.6112, alphaa=None,
Name of the specific attenuation field to use.
rr_field : str, optional
Name of the rainfall rate field.
master_field : str, optional
Name of the field that is going to act as master. Has to be
main_field : str, optional
Name of the field that is going to act as main. Has to be
either refl_field or kdp_field. Default is refl_field.
thresh : float, optional
Value of the threshold that determines when to use the slave
Value of the threshold that determines when to use the secondary
field.
thresh_max : Bool, optional
If true the master field is used up to the thresh value maximum.
Otherwise the master field is not used below thresh value.
If true the main field is used up to the thresh value maximum.
Otherwise the main field is not used below thresh value.

Returns
-------
rain_master : dict
rain_main : dict
Field dictionary containing the rainfall rate.

"""
Expand All @@ -347,44 +369,44 @@ def est_rain_rate_za(radar, alphaz=0.0376, betaz=0.6112, alphaa=None,
rain_a = est_rain_rate_a(
radar, alpha=alphaa, beta=betaa, a_field=a_field, rr_field=rr_field)

if master_field == refl_field:
slave_field = a_field
rain_master = rain_z
rain_slave = rain_a
elif master_field == a_field:
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
elif master_field is None:
master_field = a_field
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
if main_field == refl_field:
secondary_field = a_field
rain_main = rain_z
rain_secondary = rain_a
elif main_field == a_field:
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
elif main_field is None:
main_field = a_field
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
else:
master_field = a_field
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
main_field = a_field
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
thresh = 0.04
thresh_max = False
warn('Unknown master field. Using ' + a_field + ' with threshold '
warn('Unknown main field. Using ' + a_field + ' with threshold '
+ str(thresh))

if thresh_max:
is_slave = rain_master['data'] > thresh
is_secondary = rain_main['data'] > thresh
else:
is_slave = rain_master['data'] < thresh
is_secondary = rain_main['data'] < thresh

rain_master['data'][is_slave] = (
rain_slave['data'][is_slave])
rain_main['data'][is_secondary] = (
rain_secondary['data'][is_secondary])

return rain_master
return rain_main


def est_rain_rate_hydro(radar, alphazr=0.0376, betazr=0.6112, alphazs=0.1,
betazs=0.5, alphaa=None, betaa=None, mp_factor=0.6,
refl_field=None, a_field=None, hydro_field=None,
rr_field=None, master_field=None, thresh=None,
rr_field=None, main_field=None, thresh=None,
thresh_max=False):
"""
Estimates rainfall rate using different relations between R and the
Expand Down Expand Up @@ -412,15 +434,15 @@ def est_rain_rate_hydro(radar, alphazr=0.0376, betazr=0.6112, alphazs=0.1,
Name of the hydrometeor classification field to use.
rr_field : str, optional
Name of the rainfall rate field.
master_field : str, optional
Name of the field that is going to act as master. Has to be
main_field : str, optional
Name of the field that is going to act as main. Has to be
either refl_field or kdp_field. Default is refl_field.
thresh : float, optional
Value of the threshold that determines when to use the slave
Value of the threshold that determines when to use the secondary
field.
thresh_max : Bool, optional
If true the master field is used up to the thresh value maximum.
Otherwise the master field is not used below thresh value.
If true the main field is used up to the thresh value maximum.
Otherwise the main field is not used below thresh value.

Returns
-------
Expand Down Expand Up @@ -479,38 +501,38 @@ def est_rain_rate_hydro(radar, alphazr=0.0376, betazr=0.6112, alphazs=0.1,
rr_data[is_ih] = snow_z['data'][is_ih]

# rain
if master_field == refl_field:
slave_field = a_field
rain_master = rain_z
rain_slave = rain_a
elif master_field == a_field:
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
elif master_field is None:
master_field = a_field
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
if main_field == refl_field:
secondary_field = a_field
rain_main = rain_z
rain_secondary = rain_a
elif main_field == a_field:
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
elif main_field is None:
main_field = a_field
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
else:
master_field = a_field
slave_field = refl_field
rain_master = rain_a
rain_slave = rain_z
main_field = a_field
secondary_field = refl_field
rain_main = rain_a
rain_secondary = rain_z
thresh = 0.04
thresh_max = False
warn('Unknown master field. Using ' + a_field + ' with threshold ' +
warn('Unknown main field. Using ' + a_field + ' with threshold ' +
str(thresh))

if thresh_max:
is_slave = rain_master['data'] > thresh
is_secondary = rain_main['data'] > thresh
else:
is_slave = rain_master['data'] < thresh
is_secondary = rain_main['data'] < thresh

rain_master['data'][is_slave] = rain_slave['data'][is_slave]
rain_main['data'][is_secondary] = rain_secondary['data'][is_secondary]

rr_data[is_lr] = rain_master['data'][is_lr]
rr_data[is_rn] = rain_master['data'][is_rn]
rr_data[is_lr] = rain_main['data'][is_lr]
rr_data[is_rn] = rain_main['data'][is_rn]

# mixed phase
rr_data[is_ws] = mp_factor*rain_z['data'][is_ws]
Expand Down