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

Cloud and Precipitation Microphysics Retrieval for EarthCARE's Doppler
Cloud Profiling Radar Measurements
Kamil Mroz1, B. Puigdomènech Treserras2, A. Battaglia1,4,5, P. Kollias2,3, A. Tatarevic2, F. Tridon4
1National Centre for Earth Observation, UK; 2McGill University, Canada; Stony 3Brook University, USA;
4Politecnico of Turin, Italy; 5University of Leicester, UK

C-CLD overview• Only the CPR data utilized:➢ C-FMR reflectivity➢ C-CD Doppler velocity➢ C-TC classification• The algorithm is based on aprofile-by-profile approach• It is based on the Optimal
Estimation framework• Vertical distribution of 2
microphysical parameters isdetermined, i.e., water content
and characteristic size

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

C-CLD productC-CLD overview• C-CLD is composed of severalmodules• C-TC classification is used toselect the specific algorithm• Liquid cloud and light drizzle
algorithm based on thepower law relationships• Snow/cold &warm rainalgorithms are based on theOE

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

C-CLD productOE concept
The OE framework aims at balancing the information provided by:• The CPR measurements in the entire column• The statistical information on ground-based precipitation rates and sizes• Continuity of estimated quantities
𝑇 𝑅 −1 𝑦 − 𝐹 𝑥
𝑌A-priori term+ 𝑥 − 𝑥𝑎 𝑇 𝑅𝑎−1 𝑥 − 𝑥𝑎 + 𝑥 𝑇 𝑅𝑠−1 𝑥 ;Measurement component

Continuity

2𝜙 = 𝑦 − 𝐹 𝑥

F - forward modely – measured reflectivity and sedimentation velocity
x – state vector
xa – a-priori estimate of the state vector,Ry-1, Ra-1, Rx-1 - weights

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

C-CLD productOE concept: measurement term
A-priori term
𝑇 −1
𝑇 −1
2𝜙 = 𝒚 − 𝑭 𝒙 𝑻 𝑹−𝟏
𝒀 𝒚 − 𝑭 𝒙 + 𝑥 − 𝑥𝑎 𝑅𝑎 𝑥 − 𝑥𝑎 + 𝑥 𝑅𝑠 𝑥 ;Measurement componentContinuity• Scattering properties of rain are simulated using T-matrix approximation• Radar measurements are simulated using a scattering dataset that
correspond to realistic snowflake shapes via the Discrete DipoleApproximation.
• Riming is parameterized, assuming the "fill-in" model• Particle size distribution modeled as the Gamma function:
𝑁 𝐷 = Γ(𝐷; 𝐷𝑚 , 𝑊𝐶, 𝜇)where 𝜇 =𝐷𝑚 2−4 ≈𝜎𝑚−0.8 − 410𝐷𝑚

Leinonen & Szyrmer (2015)
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

C-CLD productOE concept: a-priori term
𝑇 −1
𝑅𝑌 𝑦 − 𝐹 𝑥

A-priori term
𝑇 −1+ 𝒙 − 𝒙𝒂 𝑻 𝑹−𝟏
𝒂 𝒙 − 𝒙𝒂 + 𝑥 𝑅𝑠 𝑥 ;Measurement component

Continuity

2𝜙 = 𝑦 − 𝐹 𝑥

Ice/snow (Matrosov & Heymsfield 2008, 2017):

Rain (NASA DSD dataset):
log10Dm [cm] = 0.01 Ze [dBZ] – 1.55 ±0.15 for 10 dBZ< Ze

Uncertainty in log10WC of 0.9 B
Uncertainty in log10Dm of 0.9 B

log10 Dm

Dm [cm] = 0.052 (Ze [dBZ])0.280 for snow,0.047 (Ze [dBZ])0.294 for cirrus

log10WC [g/m3] = 0.109 Ze [dBZ] – 2.93 ±0.2 for Ze >12.5dBZ= 0.038 Ze [dBZ] – 2.04 ± 0.3
for Ze <12.5dBZ

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

log10 WCWC [g/m3] = 0.086 (Ze [mm6m-3])0.92;

C-CLD productValidation: GEM simulations• Underestimate for large raindrop sizes• Insufficient number of the validation points for large

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

C-CLD productValidation needed: rain module
PDF ofdisdrometer data

Only 0.2% of CloudSat data in rain exceeds 12dBZ
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

C-CLD productValidation needed: rain module
Disdrometer + cloud probe

Vertically pointing radar

Bringi et al.
(2020)• Long integration time
• Small sampling volume• Direct DSD measurements• Short integration time
• Large sampling volume• Indirect DSD estimate:➢ Vertical wind estimate is crucial for accuracy – Wor G band system needed (Kollias et al. 2002 )➢ Lidar system needed to estimate #droplets
below 200um

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

C-CLD productValidation needed: snow/ice module

Mass-size relationship: m [kg] = ⍺ D[m]βSimulations of aggregatesriming

HIWC campaign

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

C-CLD productValidation needed: snow/ice moduleRadarNevzorov

Ice density dependent
simulations

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

C-CLD productConclusions and Future work
• C-CLD is a precipitation retrieval based on the OE framework• Information content of EC CPR measurements varies depending on hydrometeor size and type:➢ reflectivity is more informative for ice and snow
➢ mean Doppler velocity more useful in rain
• Calibration and validation activities need to focus on weather conditions not included in GEM simulations:➢ Large particle sizes➢ Warm rain conditions• C-CLD algorithm was applied to stratiform precipitation only; we can test it in convective profiles• More studies on liquid cloud detection needed• Explore potential for horizontal continuity, i.e., diverge from a profile-to-profile approach

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

C-CLD product