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

On the utility of the EarthCARE CPR Doppler observations for evaluating therepresentation of convective dynamics in regional and global high-resolution models
Pavlos Kollias1,2, Bernat Puigdomenech Treserras2, Zhuocan Xu1,
Alessandro Battaglia3,4, Kamil Mroz4
1. Stony Brook University, USA, 2. McGill University, Canada, 3. Politechico di Torino, Italy, 4. University of Leicester, UKIntroduction
The Doppler capability of the CPR is expected toprovide the first ever global observations ofconvective motions in shallow and deep convection.
Here, two topics are discussed:
Quality of the CPR Doppler velocity measurements
in shallow and deep convection
Methodologies for bridging the CPR observations
with high resolution numerical models.

Updraftcourtesy of G. Heymsfield, NASA GSFC
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

CloudSat: Convective Cores Climatology
CloudSat CPR Cloud top height (km)Using a new methodology to identify deepconvective cores (Xu et al., 2023)
Limited sampling
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy-20-10010Radar reflectivity (dBZ)

20

Use end-to-end OSSEs in convective clouds

Height (km)High resolution (100 m) simulations
Forward simulated CPR radar reflectivity
Multiple scattering effects included

Deep oceanic convection (CAMP2Ex)

Shallow warm rain (RICO)

https://espo.nasa.gov/camp2ex/content/CAMP2Ex Along track (km)https://www.eol.ucar.edu/field_projects/ricoESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), ItalydBZ

Spaceborne Doppler velocity
MDV = VAM + VSED𝜎𝑉𝐴𝑀 =22𝜎𝑀𝐷𝑉+ 𝜎𝑆𝐸𝐷

Vertical Air Motion (VAM)
Updraft
How well can we measure theDoppler velocity ?

VSED𝜎𝑀𝐷𝑉 =How well do we know thehydrometeor sedimentation
velocity (VSED)?

2𝜎𝐵2 + 𝜎𝑁𝑈𝐵𝐹+ 𝜎𝑃2~ 1 ms-1?

Downdraft
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy~ 0.15 ms-1

Relationship between VAM and VSEDWarm phase (< 4 km)

Cold phase (> 6 km)

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

Shallow Convection (RICO)
Simulated CPR radar reflectivity

Simulated CPR Best Estimate
Doppler velocity (C-CD)

Contours: [2 4 6 ms-1] updrafts

MDV = VAM + VSEDESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), ItalyDeep Convection (CAMP2Ex)Contours: [4 8 12 ms-1] updrafts

𝑍𝑀𝑆𝑑𝐵𝑍𝑆𝑆

Multiple to single scattering backscatter

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

Attenuation (MS) limits CPR penentration
Simulated CPR radar reflectivity

Simulated CPR Best Estimate Doppler
velocity (C-CD)

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

NUBF Doppler velocity bias
Non-Uniform Beam Filling (NUBF)
conditions within the CPR sampling
volume combined with the apparent
Doppler velocity introduced by thesatellite motion can result toDoppler velocity biases

Kollias et al., 2014; 2022
Sy et al., 2014; 2023
Illingworth et al., 2015
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

NUBF Doppler velocity bias
Strong NUBF velocity biases are observed in shallow convection. This reflects therelationship between the size of the convective cores in shallow and deep convection andthe CPR footprint (~800 m).

Warm phase (< 4 km)

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

Cold phase (> 6 km)

NUBF Doppler velocity residual error
After the NUBF correction is applied, the mean residual error is on average 0.3-0.4
ms-1

Cold phase (> 6 km)

Warm phase (< 4 km)

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

Doppler velocity unfolding
Contours: [4 8 12 ms-1]
updraftsDoppler(unfolded)

dBZ

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

Quick emulators for numerical models
The state-of-the-art EarthCARE CPR forward simulator can be used for:L2 algorithm development and testing
Develop fast CPR surrogate forward models for high resolution numerical models for anapples-to-apples comparison with CPR observations

High resolution
numerical model
outputL1/L2 development
E/M forwardmodel

CPR instrument
model

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

Fast surrogate models

Non-uniform Beam Filling
MC3E

TRMM-LBA

Horizontal cross-section showing vertical air motion(VAIR in ms−1; positive indicates upward motion) fromthree different model simulations: (A) MC3E at
12 km height, (B) TRMM-LBA at 10 km height,and (C) RICO at 1 km height. Overlaid circles
represent the 5, 2.5 and 1 km instantaneous fieldof view (IFOV).
NUBF is a source of Doppler velocity bias for theEarthCARE CPR.

RICONUBF is a spatial filter that should be considered inmodel – CPR intercomparisons

Kollias et al., 2022: Mind the Gap – Part 3
https://doi.org/10.3389/frsen.2022.860284
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Impact of the satellite footprint on
convective updraft properties
Normalized distribution of the relative error

𝑚𝑜𝑑𝑒𝑙−𝑟𝑎𝑑𝑎𝑟∙ 100%
𝑚𝑜𝑑𝑒𝑙(A) convective updraft fraction, (B) mean convective updraft velocity, and (C) convective updraft mass flux.
Results are shown for three different instantaneous radar field of views close to that of radar 1 (1.0 km;green), radar 5 (2.5 km; cyan), radar 4 (5.0 km; black).
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Representativeness of the CPR observations

gSAM 1 km simulation
Started from ERA5 and boundaries
are nudged to ERA5
4.6S - 18.6N, lon: 174.00E - 221E

9.5% of columns with Vmax > 2ms-1
1.4% of columns with Vmax > 5ms-1
23% of columns with WP > 0.25 kgm-2

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

EarthCARE CPR fast emulator for GSRMs

Minimum height of EC CPR
observations as function ofmodel IWP

Multiple scattering
Attenuation
Sampling limited

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

Summary
In shallow convection, the CPR excellent resolution (footprint) and sensitivity are expected to resolve shallow
and weak updrafts. The challenge is to decompose the VSED and VAM contributions to the observed CPRDoppler velocity.
In deep convection, attenuation (MS) limits the penetration depth of the CPR observations. Yet, unique, global
observations of convective motions in the upper (3-4) km of deep convective clouds are expected. The
challenge is to perform Doppler velocity unfolding.
NUBF is not a source of concern for the quality of the CPR Doppler velocities in deep convection. The
expected uncertainty in the retrieved convective vertical air motion is 1.5 - 2.0 ms-1 in shallow convection and
2.0 – 3.0 ms-1 in deep convection.

Fast CPR emulators for GSRMs and high resolution regional models should account for the penetration depth
in deep convection (i.e., parameterize as a function of IWP) and the sample size of CPR convective motions.

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