gpm.retrievals package

Submodules

gpm.retrievals.retrieval_2a_pmw module

This module contains GPM PMW 2A products community-based retrivals.

gpm.retrievals.retrieval_2a_pmw.retrieve_liquidPrecipitation(ds)

Retrieve clutter height.

gpm.retrievals.retrieval_2a_pmw.retrieve_totalWaterPath(ds)

Retrieve clutter height.

gpm.retrievals.retrieval_2a_radar module

This module contains GPM RADAR 2A products community-based retrivals.

gpm.retrievals.retrieval_2a_radar.retrieve_EchoDepth(ds, threshold, variable='zFactorFinal', radar_frequency='Ku', min_threshold=0, mask_liquid_phase=False)

Retrieve Echo Depth with reflectivity above xx dBZ.

Common thresholds are 18, 30, 50, 60 dbZ.

gpm.retrievals.retrieval_2a_radar.retrieve_EchoTopHeight(ds, threshold, variable='zFactorFinal', radar_frequency='Ku', min_threshold=0)

Retrieve Echo Top Height (maximum altitude) for a particular reflectivity threshold.

Common thresholds are 18, 30, 50, 60 dbZ. References: Delobbe and Holleman, 2006; Stefan and Barbu, 2018

gpm.retrievals.retrieval_2a_radar.retrieve_HailKineticEnergy(ds, variable='zFactorFinal', radar_frequency='Ku', lower_threshold=40, upper_threshold=50)

Compute Hail Kinetic Energy.

Lower and upper reflectivity thresholds are used to retain only higher reflectivities typically associated with hail and filtering out most of the lower reflectivities typically associated with liquid water.

gpm.retrievals.retrieval_2a_radar.retrieve_MESH(ds)

Retrieve the Maximum Estimated Size of Hail (MESH).

Also known as the Maximum Expected Hail Size (MEHS).

The “size” in MESH refers to the maximum diameter (in mm) of a hailstone. It’s an indicator that transforms SHI into hail size by fitting SHI to a chosen percentile of maximum observed hail size (using a power-law)

gpm.retrievals.retrieval_2a_radar.retrieve_POH(ds, method='Foote2005')

The Probability of Hail (POH) at the surface.

Based on EchoDepth45dBZ above melting layer.

No hail if EchoDepth45dBZ above melting layer < 1.65 km. 100% hail if EchoDepth45dBZ above melting layer > 5.5 / 5.8 km. to 100% (hail; Δz > 5.5 km)

Reference:

• Foote et al., 2005. Hail metrics using conventional radar.

Output probabilities are rounded off to the nearest 10%, to avoid

conveying an unrealistic degree of precision.

gpm.retrievals.retrieval_2a_radar.retrieve_POSH(ds)

The Probability of Severe Hail (POSH).

The probability of 0.75-inch diameter hail occurring.

When SHI = WT, POSH = 50%. Output probabilities are rounded off to the nearest 10%, to avoid conveying an unrealistic degree of precision.

gpm.retrievals.retrieval_2a_radar.retrieve_REFC(ds, variable='zFactorFinal', radar_frequency='Ku', mask_bright_band=False, mask_solid_phase=False, mask_liquid_phase=False)

Retrieve the vertical maximum radar reflectivity in the column.

Also called: Composite REFlectivity

gpm.retrievals.retrieval_2a_radar.retrieve_REFCH(ds, variable='zFactorFinal', radar_frequency='Ku')

Retrieve the height at which the maximum radar reflectivity is observed.

Also called: Composite REFlectivity Height

gpm.retrievals.retrieval_2a_radar.retrieve_SHI(ds, variable='zFactorFinal', radar_frequency='Ku', lower_z_threshold=40, upper_z_threshold=50)

Retrieve the Severe Hail Index (SHI).

SHI is used to compute the Probability of Severe Hail (POSH) and Maximum Estimated Size of Hail (MESH). SHI applies a thermally weighted vertical integration of reflectivity from the melting level to the top of the storm, neglecting any reflectivity less than 40 dBZ, thereby attempting to capture only the ice content of a storm.

Reference: Witt et al., 1998

Parameters:

• ds (TYPE) – DESCRIPTION.

• variable (str, optional) – Reflectivity field. The default is “zFactorFinal”.

• radar_frequency (str, optional) – Radar frequency. The default is “Ku”.

• lower_z_threshold ((int, float), optional) – Lower reflectivity threshold. The default is 40 dBZ.

• upper_z_threshold ((int, float), optional) – Upper reflectivity threshold. The default is 50 dBZ.

Returns:

da_shi – Severe Hail Index (SHI)

Return type:

xr.DataArray

gpm.retrievals.retrieval_2a_radar.retrieve_VIL(ds, variable='zFactorFinal', radar_frequency='Ku')

Compute Vertically Integrated Liquid indicator.

Represents the total amount of rain that would fall if all the liquid water in a column inside a rain cloud (usually a thunderstorm) would be brought to the surface.

Reference:

Greene, D.R., and R.A. Clark, 1972: Vertically integrated liquid water - A new analysis tool. Mon. Wea. Rev., 100, 548-552. Amburn and Wolf (1997)

gpm.retrievals.retrieval_2a_radar.retrieve_VILD(ds, variable='zFactorFinal', radar_frequency='Ku', threshold=18, use_echo_top=True)

Compute Vertically Integrated Liquid Density.

VIL Density = VIL/Echo Top Height

By default, the Echo Top Height (or Echo Depth) is computed for 18 dBZ. More info at https://www.weather.gov/lmk/vil_density

gpm.retrievals.retrieval_2a_radar.retrieve_dfrFinal(ds)

Retrieve final DFR.

gpm.retrievals.retrieval_2a_radar.retrieve_dfrFinalNearSurface(ds)

Retrieve final DFR near the surface.

gpm.retrievals.retrieval_2a_radar.retrieve_dfrMeasured(ds)

Retrieve measured DFR.

gpm.retrievals.retrieval_2a_radar.retrieve_heightClutterFreeBottom(ds)

Retrieve clutter height.

gpm.retrievals.retrieval_2a_radar.retrieve_heightRealSurfaceKa(ds)

Retrieve height of real surface at Ka band.

gpm.retrievals.retrieval_2a_radar.retrieve_heightRealSurfaceKu(ds)

Retrieve height of real surface at Ku band.

gpm.retrievals.retrieval_2a_radar.retrieve_precipitationType(xr_obj, method='major_rain_type')

Retrieve major rain type from the 2A-<RADAR> typePrecip variable.

gpm.retrievals.routines module

This module contains functions to search the GPM-API community-based retrivals.

gpm.retrievals.routines.available_retrievals(ds)

Decode the variables of a given GPM product.

gpm.retrievals.routines.check_retrieval_validity(ds, retrieval)

Check retrieval validity.

gpm.retrievals.routines.get_retrieval_variable(ds, name, *args, **kwargs)

Compute the requested variable.

Module contents

This directory contains the GPM-API community-based retrievals encodings.