ESA-JAXA Pre-Launch EarthCARE
Science and Validation
Workshop

13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Representativityof air- and spaceborne radar-lidar measurements
Florian Ewald1, Silke Groß1, Martin Wirth1, Julien Delanoe2, Clemantyne Aubry1,2
1) German Aerospace Center (DLR), Institut of Atmospheric Physics, Germany2) LATMOS/IPSL/UVSQ/CNRS, Guyancourt, France

The challenge – a seamless transition
A-Train(NASA)

CalVal between A-Train and EarthCARE

1a) Influence of different platforms?
1b) Influence of different algorithms?
2) Representativity of airborne validation campaigns?

Bridging the gap via underflights and statistical sampling

EarthCARE(ESA/JAXA)The airborne platform – HALO Remote Sensing Payload
An airborne testbed to anticipate EarthCARE- G550, max. alt 16 km / max. range: 8000 km- In operation since 2012
- operated by DLR

specMACSa)

WALESb)Scientific Instruments
HSRL-Lidar (WALES, 532 nm – Wirth et al. 2009)
Cloud-Profiling Radar (MIRA, 35 GHz – Ewald et al. 2019)
Hyper-Spektral Imager (specMACS – Ewald et al. 2016)
Microwave Radiometer (HAMP – Mech et al. 2014)c)

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

MIRA

The influence of different platforms
Underflights of the A-Train (NASA) with HALO (DLR)

A-Train algorithm

A-TrainSpaceborne

HALO

Airborne

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

Influence of different platforms – airborne vs spaceborne
Underflights of the A-Train (NASA) with HALO (DLR)
A-Train
A-TrainCALIOP (532 nm)
CloudSat (94 GHz)
HALO
HALO
WALES (532 nm)
MIRA (35 GHz)

HALO
A-Train

NARVAL campaigns
2013 - 2016
Base: Iceland / Barbados
Area: Full atlantic
Aim: Ice / marine clouds
17x A-Train underpasses
Demo Flight 2 ➜(2013/07/24)
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Influence of different platforms – measurements

12:22

Ze 94 GHz
12:21

12:20

12:19

12:18

12:17

12:16

12:15

12:14

Radar reflectivity Z - HAMP MIRA, 35 GHz [dBZ]

HALO
12:22

Ze 35 GHz
12:21

12:20

12:19

12:18

12:17

12:16

12:15

12:14

30
20
100°10°20°30°40°50°601412108
642010°4
10°5

A-Train12:22

βa 532 nm
12:21

12:20

12:19

12:18

12:17

12:16

12:15

10°6

[m°1 sr°1]

1412
108
64
20Attenuated Backscatter coefficient Ø a - CALIOP, 532 nm [m°1 sr°1]

10°7

12:14Attenuated Backscatter coefficient Ø a - WALES, 532 nm [m°1 sr°1]
10°4
10°5

βa 532 nm

HALO
12:2212:21

12:20

12:19

12:18

12:17

→ Observation: similar sensitivity for ice clouds but coarser spatial resolution
and more noise in spaceborne measurements
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

12:16

12:15

12:14

10°610°7[m°1 sr°1]

14121086420A-Train

3020
100°10°20°30°40°50°60[dBZ] [km]Height (AMSL)

14121086420Radar reflectivity Z - CloudSat, 94 GHz [dBZ][dBZ] [km]Height (AMSL)Height (AMSL) [km]Height (AMSL) [km]Underflights of the A-Train (NASA) with HALO (DLR)

Influence of different platforms – ice cloud retrievals

10°2A-Train
12:22

IWC
12:21

12:20

12:19

12:18

12:17

12:16

12:15

10°3
10°4

12:14

Retrieved Ice Water Content - MIRA/WALES [g m °3]

100
10°1
10°2

HALO
12:22

IWC
12:21

12:20

12:19

12:18

12:17

12:16

12:15

12:14

10°3
10°4

14121086420

Retrieved effective radius - CloudSat/CALIOP [µm]1009080706050403020
100[µm]10°1

14121086420A-Train
12:22

reff
12:21

12:20

12:19

12:18

12:17

12:16

12:15

12:14

Retrieved effective radius - MIRA/WALES [µm]10090807060504030
20100[µm]14121086420100

Height[g(AMSL)
m°3] [km]14121086420

Retrieved Ice Water Content - CloudSat/CALIOP [g m °3]

Height[g(AMSL)
m°3] [km]Height (AMSL) [km]Height (AMSL) [km]Underflights of the A-Train (NASA) with HALO (DLR)

reff

HALO
12:22

12:21

12:20

12:19

12:18

12:17

12:16

→ Observation: similar retrieved values between platforms while the spaceborne datais missing the fine-scale structures of cloud microphysics
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

12:15

12:14

Influence of different platforms – ice cloud retrievals

MedianHALO
A-TrainMedianUnderflights of the A-Train (NASA) with HALO (DLR)

HALO
A-Train- Ice water content: +10% larger with narrower distribution for A-Train- Effective radius: -5% smaller with slighly narrower distribution for A-Train→ Conclusion: slightly lower sensitivity and coarser spatial resolution ofspaceborne instruments leads to more narrow distributions of cloud properties
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

The influence of different algorithms

DARDAR and CAPTIVATE on the same A-Train granule

A-Train retrieval

DARDAR
A-TrainEarthCARE retrieval

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

Spaceborne2007/01/02
16:27 – 16:30

CALIPSO Track

MODIS Aqua
Band 31 (10.8 μm)

Influence of different retrievals – measurements /retrieval
DARDAR and CAPTIVATE on the same A-Train granuleSame input (Ze and βa only)

HALO

Ze 94 GHzβa 532 nm
HALO

DARDARCAPTIVATE

v2.23 with variable, higher LR DARDAR

CAPTIVATE v1.1.13 with const, low LR for lidar only

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

Representativity of validation campaigns

Can we validate EarthCARE using airborne measurement campaigns?

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

Representativity of validation campaigns – Overview
All DLR airborne measurements during NARVAL-I / -II and NAWDEX

Tropical North-Atlantic• NARVAL-I: 10 – 20 Dec 2013 (dry season)• NARVAL-II: 8 – 29 Aug 2016 (wet season)
Extra-tropical North-Atlantic• NARVAL-I: 7 – 22 Jan 2014
• NAWDEX: 15 Sep – 18 Oct 2016
• ~310 flight hours• 17 coordinated A-Train underpass• 6 coordinated HALO – FF20 legs (NAWDEX)
Coordinated flights with HALO, DLR Falcon, SAFIRE Falcon (+ A-Train) during NAWDEXESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Representativity of validation campaigns – NAWDEXWas the NAWDEX airborne campaign representative in comparison with A-Train?
NAWDEX campaign (HALO) 16.09. – 16.10.2016

13 HALO Flights(0.5 x per day, 80h, 60.000 km)

DARDAR dataset (A-Train)

61 A-Train Overpasses (noon)(2 x per day, 4h, 100.000 km)→ Approach: Comparison of ERA5 ice cloud statistics along HALO flight pathwith ERA5 ice cloud statistics of full domain
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

NAWDEX campaign – Representativity of HALO flights
ERA5 IWC statistics along HALO flight path compared to full domain

ERA5 (TIWC, Full domain)
520010200210210

220

220
104230

230
240
250
260
270280 °51010°4 10°3 10°2 10°1 100 101
In-cloud ice + snow water content [g/m3]

Temperature [K]Temperature [K]ERA5 (TIWC, HALO Track)

Counts
105

104

240

250
103
260

103

270210280
10°5 10°4 10°3 10°2 10°1 100 101
In-cloud ice + snow water content [g/m3]- Shape and relative frequency of IWC-T profile along the HALO flight pathmatches with the IWC-T profile for the full model domain→ Conclusion: NAWDEX flights were representative for ice clouds!
ESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

102

NAWDEX campaign – Comparison between platforms
Comparison of IWC statistics between HALO and A-Train
VarCloud (HALO)DARDAR (A-Train)

200

105Log(Counts)

210
Temperature [K]

220
104

230
240
250

103

260
270
280 °51010°4 10°3 10°2 10°1 100
Ice water content [g/m3]

101

102

- With ERA5: Slighly different profile shape, with missing low IWC values in ERA5
- With A-Train: Overall agreement of profile shape, but missing sensitivity for thin clouds
and slight higher IWCs at higher temperatures from A-TrainESA-JAXA Pre-Launch EarthCARE Science and Validation Workshop | 13 – 17 November 2023 | ESA-ESRIN, Frascati (Rome), Italy

Summary – Representativity of radar-lidar products… and bridging the gap between A-Train and EarthCARE via airborne campaigns

1) How well do airborne and spaceborne retrieval results agree?
→ “Similar mean retrieval results, with narrower distributionsof retrieved ice water content and particle sizes from A-Train”
2) How well do the retrievals DARDAR and CAPTIVATE agree?
→ “Without HSRL, Doppler and solar radiances, very similar results for
thick ice clouds, with larger differences in reff for thin cirrus. ”
3) How representative were airborne campaigns w.r.t ice cloud statistics?
→ “No significant sampling bias detected in IWC-T statistics whilesensitivity and resolution have their impact on ice cloud statistics”

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