ESA-JAXA Pre-Launch EarthCARE
Science and Validation Workshop
13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

K2W, a methodology for evaluating spaceborne W-band Doppler radar using
Micro Rain Radar and disdrometer: results from an Italian station in Antarctica
A. Bracci 1, K. Sato 2, L. Baldini 1, F. Porcù 3, H. Okamoto 2
1 Institute of Atmospheric Sciences and Climate (CNR-ISAC), Rome, Italy

2 Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan
3 Department of Physics and Astronomy, University of Bologna, Bologna, Italy

Rationale
Importance of Antarctic precipitation

Observing and Modeling Ice Sheet Surface Mass Balance(10.1029/2018RG000622)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Importance of Antarctic precipitation
Surface Mass Balance of Antarctic Ice Sheet(AIS)

Observing and Modeling Ice Sheet Surface Mass Balance(10.1029/2018RG000622)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Importance of Antarctic precipitation
Surface Mass Balance of Antarctic Ice Sheet(AIS)o During precipitation andaccumulates at the surface

depositionmasso Snowfall is the primary input of mass for the AIS
and its variability and change have an impact on
the ice sheet mass balance

Observing and Modeling Ice Sheet Surface Mass Balance(10.1029/2018RG000622)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Importance of Antarctic precipitation
Surface Mass Balance of Antarctic Ice Sheet(AIS)o During precipitation andaccumulates at the surface

depositionmasso Snowfall is the primary input of mass for the AIS
and its variability and change have an impact on
the ice sheet mass balance

Impact on global sea level

Observing and Modeling Ice Sheet Surface Mass Balance(10.1029/2018RG000622)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
What do we know about Antarctic precipitation?

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
What do we know about Antarctic precipitation?
Unfortunately, not much

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
What do we know about Antarctic precipitation?
Unfortunately, not mucho Ground-based observations of precipitation are sparse over
Antarctica, due also to complex logistical operations, extreme
climatic conditions, difficult accessibility and instrument
maintenance

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
What do we know about Antarctic precipitation?
Unfortunately, not mucho Ground-based observations of precipitation are sparse over
Antarctica, due also to complex logistical operations, extreme
climatic conditions, difficult accessibility and instrument
maintenanceo Precipitation estimations over the Continent rely on numericalmodel and satellite measurementso Both need ground observations for validating and improving
precipitation parameterizations and for minimizing the impact
of intrinsic limitations of the measurement techniques

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

CloudSat: Mean annual snowfall over Antarctica(Milani et al., 2018)

Rationale
Availability of ground-based radar profilers for validation purposes

Neumayer-Station III
Princess Elisabeth
StationAmundsen–Scott
South Pole Station

Davis Station
Vostok Station
Concordia Station
Dumont d'Urville
Station
McMurdo Station

Mario
(MZS)
MarioZucchelli
Zucchelli

Research stations (precipitation monitoring)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Availability of ground-based radar profilers for validation purposeso W-band radars:o Mc-Murdo (Lubin, 2020) T
o Davis (Alexander, 2023) T

Neumayer-Station III
Princess Elisabeth
StationAmundsen–Scott
South Pole Station

Davis Station
Vostok Station
Concordia Station
Dumont d'Urville
Station
McMurdo Station

Mario
(MZS)
MarioZucchelli
Zucchelli

Research stations (precipitation monitoring)

T=temporary; F= fixed; P=planned
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Availability of ground-based radar profilers for validation purposeso W-band radars:o Mc-Murdo (Lubin, 2020) T
o Davis (Alexander, 2023) T

Neumayer-Station III
Princess Elisabeth
Stationo Ka-band radars:o Mc-Murdo (Lubin, 2020) T
o Neumayer III (Radenz, 2023) F

Amundsen–Scott
South Pole Station

Davis Station
Vostok Station
Concordia Station
Dumont d'Urville
Station
McMurdo Station

Mario
(MZS)
MarioZucchelli
Zucchelli

Research stations (precipitation monitoring)

T=temporary; F= fixed; P=planned
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Rationale
Availability of ground-based radar profilers for validation purposeso W-band radars:o Mc-Murdo (Lubin, 2020) T
o Davis (Alexander, 2023) To Ka-band radars:o Mc-Murdo (Lubin, 2020) T
o Neumayer III (Radenz, 2023) F

Neumayer-Station III
Princess Elisabeth
StationAmundsen–Scott
South Pole Station

Davis Stationo K-band radars:
o
o
o
o
o
o
o

4 @ Princess Elisabeth (Gorodetskaya, 2015; Ferrone, 2023) F T T T
1 @ Dumont D’Urville (Grazioli, 2017) F
2 @ Mario Zucchelli (Scarchilli, 2020; Bracci, 2022) F F
1 @ Concordia (Di Natale, 2022) F
1 @ Vernadsky (Pishniak, 2022) F
1 @ Davis (Alexander,2023) F
T=temporary; F= fixed; P=planned
1 @ Marambio P

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Vostok Station
Concordia Station
Dumont d'Urville
Station
McMurdo Station

Mario
(MZS)
MarioZucchelli
Zucchelli

Research stations (precipitation monitoring)Rationale
Availability of ground-based radar profilers for validation purposeso W-band radars:o Mc-Murdo (Lubin, 2020) T
o Davis (Alexander, 2023) To Ka-band radars:o Mc-Murdo (Lubin, 2020) T
o Neumayer III (Radenz, 2023) F

Neumayer-Station III
Princess Elisabeth
StationAmundsen–Scott
South Pole Station

Davis Stationo K-band radars:
o
o
o
o
o
o
o

4 @ Princess Elisabeth (Gorodetskaya, 2015; Ferrone, 2023) F T T T ✓1 @ Dumont D’Urville (Grazioli, 2017) F ✓2 @ Mario Zucchelli (Scarchilli, 2020; Bracci, 2022) F F ✓1 @ Concordia (Di Natale, 2022) F ✓1 @ Vernadsky (Pishniak, 2022) F
1 @ Davis (Alexander,2023) F ✓T=temporary; F= fixed; P=planned
1 @ Marambio P

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Vostok Station
Concordia Station
Dumont d'Urville
Station
McMurdo Station

Mario
(MZS)
MarioZucchelli
Zucchelli

Research stations (precipitation monitoring)K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler SpectraoMetek - MRR is a K-band profiling Doppler radar, typically used in verticalpointing mode to derive Doppler spectra in 64 bins over 32 vertical range
bins. Set with 35 m as vertical resolution -> range probed: 105-1050 m a.g.l.

o

OTT - Parsivel is an optical laser disdrometer that measures the sizes and fallvelocities of the hydrometeors (binned in 32 × 32 diameter/speed classes)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

PARSIVELMRR

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler SpectraoMetek - MRR is a K-band profiling Doppler radar, typically used in verticalpointing mode to derive Doppler spectra in 64 bins over 32 vertical range
bins. Set with 35 m as vertical resolution -> range probed: 105-1050 m a.g.l.

o

OTT - Parsivel is an optical laser disdrometer that measures the sizes and fallvelocities of the hydrometeors (binned in 32 × 32 diameter/speed classes)o

PARSIVEL

MRR

MRR and Parsivel have been installed since December 2016 at Mario
Zucchelli Station (MZS) in the framework of the project “Antarctic
Precipitation Properties” (APP) of the Italian National Antarctic Research
Program (PNRA)

MZSESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler SpectraoMetek - MRR is a K-band profiling Doppler radar, typically used in verticalpointing mode to derive Doppler spectra in 64 bins over 32 vertical range
bins. Set with 35 m as vertical resolution -> range probed: 105-1050 m a.g.l.

o

OTT - Parsivel is an optical laser disdrometer that measures the sizes and fallvelocities of the hydrometeors (binned in 32 × 32 diameter/speed classes)o

MRR and Parsivel have been installed since December 2016 at Mario
Zucchelli Station (MZS) in the framework of the project “Antarctic
Precipitation Properties” (APP) of the Italian National Antarctic Research
Program (PNRA)oExtensive DDA database of single-scattering properties of simulated pristine
crystals and aggregate particles (Kuo, JAMC-2016) was selected, being themost comprehensive database including the K-band and W-band
simulations. We considered aggregate particles during CloudSat overpass
based on habit classification (Bracci, RS-2021)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

PARSIVELMRR

MZSK2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

Spectral reflectivity density with respect to Doppler velocity:

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

η(s, R)η𝑣 𝑣𝑠 , R =Δv

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

Spectral reflectivity density with respect to Doppler velocity:

II.

Particle size distribution is obtained by:I.
II.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:I.
II.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

MRR Retrieval(Peters, 2002)

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:
I.
II.

III.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

Making explicit the frequency dependencies:
N D =η𝐷,𝐾 D
C𝑏𝑘,𝐾 (D)as well as

N D =η𝐷,𝑊 D
C𝑏𝑘,𝑊 (D)considering same snow habit

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

MRR Retrieval(Peters, 2002)

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:
I.
II.

III.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

Making explicit the frequency dependencies:
N D =η𝐷,𝐾 D
C𝑏𝑘,𝐾 (D)as well as

N D =η𝐷,𝑊 D
C𝑏𝑘,𝑊 (D)considering same snow habit

IV. Going backwards:
η𝑣,𝑊 𝑣 = η𝑣,𝐾 𝑣

C𝑏𝑘,𝑊 𝐷
C𝑏𝑘,𝐾 (D)ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

MRR Retrieval(Peters, 2002)

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:
I.
II.

III.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

Making explicit the frequency dependencies:
N D =η𝐷,𝐾 D
C𝑏𝑘,𝐾 (D)as well as

N D =η𝐷,𝑊 D
C𝑏𝑘,𝑊 (D)considering same snow habit

IV. Going backwards:
η𝑣,𝑊 𝑣 = η𝑣,𝐾 𝑣

C𝑏𝑘,𝑊 𝐷
C𝑏𝑘,𝐾 (D)η𝑣,𝑊 𝑣𝑠 = η𝑣,𝐾 𝑣𝑠

C𝑏𝑘,𝑊 𝑣 = 𝑔(𝐷)C𝑏𝑘,𝐾 𝑣 = 𝑔(𝐷)ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

MRR Retrieval(Peters, 2002)

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:
I.
II.

III.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

Making explicit the frequency dependencies:
N D =η𝐷,𝐾 D
C𝑏𝑘,𝐾 (D)as well as

N D =η𝐷,𝑊 D
C𝑏𝑘,𝑊 (D)considering same snow habit

IV. Going backwards:
C𝑏𝑘,𝑊 𝐷
η𝑣,𝑊 𝑣 = η𝑣,𝐾 𝑣
C𝑏𝑘,𝐾 (D)η𝑣,𝑊 𝑣𝑠C𝑏𝑘,𝑊 𝑣 = 𝑔(𝐷)= η𝑣,𝐾 𝑣𝑠
C𝑏𝑘,𝐾 𝑣 = 𝑔(𝐷)ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Ze,W
VD,W

MRR Retrieval(Peters, 2002)

K2W methodology
Simulation of Doppler spectra at W-band using K-band Doppler Spectra
I.

II.

Spectral reflectivity density with respect to Doppler velocity:

Particle size distribution is obtained by:
I.
II.

III.

Expressing spectral reflectivity density with respect to particle diameter
Dividing by backscattering cross-section

η(s, R)η𝑣 𝑣𝑠 , R =
Δv
𝜕𝑣
𝜕D
η𝐷 D
N D =
C𝑏𝑘 (D)ηD D = η𝑣 v

MRR Retrieval(Peters, 2002)

Making explicit the frequency dependencies:
η𝐷,𝐾 DN D =C𝑏𝑘,𝐾 (D)as well as

η𝐷,𝑊 DN D =C𝑏𝑘,𝑊 (D)considering same snow habit

IV. Going backwards:
C𝑏𝑘,𝑊 𝐷
η𝑣,𝑊 𝑣 = η𝑣,𝐾 𝑣
C𝑏𝑘,𝐾 (D)η𝑣,𝑊 𝑣𝑠C𝑏𝑘,𝑊 𝑣 = 𝑔(𝐷)= η𝑣,𝐾 𝑣𝑠
C𝑏𝑘,𝐾 𝑣 = 𝑔(𝐷)ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Ze,W
VD,W

K2W

Results
DATA @MZS
Consistency test
Nov 2019 – Feb 2020
CloudSat overpass
4 December 2018

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results
o Consistency testo Dataset of >9000 min of solid precipitation collected by MRR and disdrometer

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results
o Consistency testo Dataset of >9000 min of solid precipitation collected by MRR and disdrometero Agree for most frequent reflectivity values (~10 dBZ) and Doppler velocities (1-min time resol.)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results
o Consistency testo Dataset of >9000 min of solid precipitation collected by MRR and disdrometero Agree for most frequent reflectivity values (~10 dBZ) and Doppler velocities (1-min time resol.)o Set trade-off for averaging time required for the most reliable correspondence

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results
o Consistency testo Dataset of >9000 min of solid precipitation collected by MRR and disdrometero Agree for most frequent reflectivity values (~10 dBZ) and Doppler velocities (1-min time resol.)o Set trade-off for averaging time required for the most reliable correspondence

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time series

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time serieso W-band values lower than K-band

K2W W-band (v(D) from disdrometer)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time serieso W-band values lower than K-bando Impact of v(D) relationship used in K2W
K2W W-band (v(D) from disdrometer)

K2W W-band (literature v(D): Unrimed Plane)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
K2W W-band (literature v(D): Unrimed Aggregates)o Radar Reflectivity time serieso W-band values lower than K-bando Impact of v(D) relationship used in K2W
K2W W-band (literature v(D): Rimed Dendrites)

K2W W-band (literature v(D): Unrimed Plane)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time serieso W-band values lower than K-bando Impact of v(D) relationship used in K2W

o Doppler Velocity time series

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time serieso W-band values lower than K-bando Impact of v(D) relationship used in K2W

o Doppler Velocity time serieso Similar values for velocity <1.5ms-1
o Vd,K > Vd,W for v > 1.5 ms-1

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

K2W W-band (v(D) from disdrometer)

Resultso K2W: Simulation of W-band Doppler Spectra

CloudSat overpass
MRR K-band

o Radar Reflectivity time serieso W-band values lower than K-bando Impact of v(D) relationship used in K2W

o Doppler Velocity time series

K2W W-band (v(D) from disdrometer)o Similar values for velocity <1.5ms-1
o Vd,K > Vd,W for v > 1.5 ms-1
o Large differences using literature v(D)K2W W-band (literature v(D): Rimed Dendrites)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
o Comparison CloudSat-K2W profileso Overpass: 5:00 UTC on 4 December 2018o Minimum distance from MZS: 22.9 km
o Lowest CloudSat range gates (720, 960 m a.s.l)o 8 MRR range gates averaged to match CS vertical resolution
o 15 ms-1 horizontal wind speed at the ground -> moving speed ofprecipitating system (first approximation)

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

CloudSat nearest
profileESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

CloudSat nearest
profileMRR K-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

CloudSat nearest
profileMRR K-band

K2W W-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

W-band(Maahn, 2014)

CloudSat nearest
profileMRR K-band

K2W W-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

W-band(Maahn, 2014)

CloudSat nearest
profileMRR K-band

K2W W-band

ΔZe: 1 dB at 960 m
ΔZe : 0.2 dB at 720 m
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity
CloudSat(mean 18 profiles)

W-band(Maahn, 2014)

Doppler Velocity

CloudSat nearest
profileMRR K-band

K2W W-band

ΔZe: 1 dB at 960 m
ΔZe : 0.2 dB at 720 m
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity

Doppler Velocity
K2W W-band

CloudSat(mean 18 profiles)

W-band(Maahn, 2014)

CloudSat nearest
profileMRR K-band

K2W W-band

ΔZe: 1 dB at 960 m
ΔZe : 0.2 dB at 720 m
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
Radar Reflectivity

Doppler Velocity
K2W W-band

CloudSat(mean 18 profiles)

CloudSat nearest
profileSD<0.2 ms-1

W-band(Maahn, 2014)

MRR K-band

K2W W-band

ΔZe: 1 dB at 960 m
ΔZe : 0.2 dB at 720 m
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
o Radar Reflectivity (sensitivity analysis)o Change time window and distance from
MZS to consider spatial variability of
precipitation during CloudSat overpass

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
o Radar Reflectivity (sensitivity analysis)o Change time window and distance from
MZS to consider spatial variability of
precipitation during CloudSat overpass
Narrowing•

1-min: K2W fails toconvert•

10-min: ΔZe>1.4dB

CS nearest
MRR K-band
K2W W-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

CS nearest
CS mean 18 pr.
MRR K-band
K2W W-band

Results: Comparison CloudSat-K2W profiles
o Radar Reflectivity (sensitivity analysis)o Change time window and distance from
MZS to consider spatial variability of
precipitation during CloudSat overpass
Widening

Narrowing•

1-min: K2W fails toconvert•Profiles start to be quitedistinct•

10-min: ΔZe>1.4dB•

Led to worsening ofcorresponde

CS nearest
MRR K-band
K2W W-band

CS nearest
CS mean 18 pr.
MRR K-band
K2W W-band

CS nearest
CS mean 82 pr.
MRR K-band
K2W W-band

CS nearest
CS mean 180 pr.
MRR K-band
K2W W-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Results: Comparison CloudSat-K2W profiles
o Radar Reflectivity (sensitivity analysis)o Change time window and distance from
MZS to consider spatial variability of
precipitation during CloudSat overpass
Widening

Narrowing•

1-min: K2W fails toconvert•Profiles start to be quitedistinct•

10-min: ΔZe>1.4dB•

Led to worsening ofcorrespondeBest correspondence for 25-min time averaging
Good agreement for 10-30 min time averaging< CPR calibration error (2dB)

CS nearest
MRR K-band
K2W W-band

CS nearest
CS mean 18 pr.
MRR K-band
K2W W-band

CS nearest
CS mean 82 pr.
MRR K-band
K2W W-band

CS nearest
CS mean 180 pr.
MRR K-band
K2W W-band

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Conclusionso Satellites are the major source of information about precipitation in Antarctica -> development of a reliable
validation strategy for the satellite measurements is in high demando K2W methodology combines MRR Doppler spectra and disdrometer data to simulate 94 GHz reflectivity andDoppler measurementso K2W was assessed using CloudSat overpass over MZS for a typical snowfall event:o K2W reproduces CloudSat Ze profile with 0.2 dB mean difference at the lowest radar range bin and 0.5 dB difference on
average below 1 km altitude
o K2W simulates the Ze profile within the CloudSat blind zones. This unattenuated W-band profile can be used to evaluate
spaceborne W-band radar retrievalso K2W simulates the W-band Doppler velocity below 1 km altitude that will be observed by EarthCARE

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Conclusionso Satellites are the major source of information about precipitation in Antarctica -> development of a reliable
validation strategy for the satellite measurements is in high demando K2W methodology combines MRR Doppler spectra and disdrometer data to simulate 94 GHz reflectivity andDoppler measurementso K2W was assessed using CloudSat overpass over MZS for a typical snowfall event:o K2W reproduces CloudSat Ze profile with 0.2 dB mean difference at the lowest radar range bin and 0.5 dB difference on
average below 1 km altitude
o K2W simulates the Ze profile within the CloudSat blind zones. This unattenuated W-band profile can be used to evaluate
spaceborne W-band radar retrievalso K2W simulates the W-band Doppler velocity below 1 km altitude that will be observed by EarthCARE

o More details about K2W methodology can be found in:

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Outlooks
o Pairs of MRR-disdrometer are available in many ground observation sites worldwide and in most of theresearch stations in Antarctica -> K2W method has a wide application

Data from Ebell, Zenodo-2020

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Outlooks
o Pairs of MRR-disdrometer are available in many ground observation sites worldwide and in most of theresearch stations in Antarctica -> K2W method has a wide applicationo New tests of K2W methodology:o Ny-Ålesund (Svalbard): Solid precipitation with a collocated ground-based MRR, disdrometer and W-band radaro L’ Aquila (Italy): Liquid/solid precipitation with a collocated ground-based MRR, disdrometer and W-band radar(take a look at the poster by Montopoli et al.)Data from Ebell, Zenodo-2020

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Thanks for your attention!
a.bracci@isac.cnr.it

ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy