Introduction to ESA campaigns and Pre-launch
lessons learned
2nd ESA EarthCARE Validation Workshop
25-28 May 2021 (online)
ESA UNCLASSIFIED – For ESA Official Use Only

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Why these campaigns?
• Improve our understanding of EarthCare measurements• Develop and improve synergistic retrievals by bringing realmeasurements close enough to EarthCare but with even more
information• A very welcome rehearsal thanks to A-Train, flight strategies, way tocompare measurements etc.
• …

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WHAT CAN WE LEARN VIA DIRECTCOMPARISONS
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EarthCARE – Pre-launch campaign activities
NARPEX (HALO with Radar-Lidar payload)
NARVAL-I south

NARVAL-I north•Base: Barbados•

Base: Iceland•Period: 10 – 20 Dec. 2013

•Period: 7 – 22 Jan. 2014

Summary: ~120 flight hours; 11 coordinated A-Train underpasses
Objectives:- Use of different radar / lidar wavelengths (measurements and calculations)- Comparing airborne and space borne radar / lidar measurements (resolution / measurementrange)- Studying small scale structures with airborne and space borne lidar
4Comparing airborne and space-borne measurements5Comparing airborne and space-borne measurements
24 July 2013

HALOA-Train

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Comparing small scale structures
CALIPSO underpasses

Direct comparisonof cloud top height
derived fromairborne and spaceborne lidaràGood agreement within +/- 200 m height for up to 400 sec time difference
7Comparing small scale structures
All flights/measurements during NARVALàUnderestimation of small scale structures with coarser resolution8

www.DLR.de • Chart 9

TEAM UP TO IMPROVE OUR UNDERSTANDING– TEST RETRIEVALS AND CLOSURE
9Airborne tandem-platforms
Remote sensing measurements on HALO and SAFIREHALOAircraft:• Modified Gulfstream G550 business jet• Endurance: > 10 flight hours• Maximum cruising altitude: > 15 km
Payload:• High spectral resolution lidar (532 nm) and watervapor DIAL
• Doppler Cloud Radar (35 GHz)
• Hyper-spectral radiometer (specMACS)

SAFIRE
Aircraft:• Dassault Falcon 20-E5• Endurance: 3.5 flight hours• Maximum cruising altitude: 13 km
Payload:• High spectral resolution lidar (355 nm)• Doppler Cloud Radar (94 GHz)
• IR radiometer• Microwave radiometer10

EarthCARE – Pre-launch campaign activities
EPATAN (FF20 – HALO; both with Radar-Lidar payload)
28th of September to 17th of October 2016
• Number of scientific flights (FF20): 15• Number of scientific flight hours (FF20): 46.5
• Number of released dropsondes (FF20): 59• Number of CloudSat-CALIPSO underpasses: 3• Number of co-located flight legs: 5
Common flights of French F20 (red) and HALO (black)
during NAWDEX. Common flight tracks are marked blue.

Objectives:- Use of different radar / lidar wavelengths / different sensitivity (joint flights)- Contribute to a better understanding of EarthCARE measurements- First rehearsal of cal/val strategy (ensuring readiness of the systems)
11Synergistic Radar/Lidar retrieval
Testing and further development
Optimal estimation approach (Delanoë and Hogan., 2008)
State vector x
A priori profile of α, S, N

Forward modeling of measurements
Lidar signalincl. multiple scattering

Radar signal
LUT based reflectivities

Comparison with measurements
WALES/MIRA or CALIOP/CloudSat
yesnoconverged?

Microphysical properties
Calculate IWC and reff

Gauss-Newton iteration
Derive new state vector x

Cazenave et al., 201912

Closure study – Radar-Lidar vs. specMACS
à Forward modeling of spectral radiances using
microphysical properties derived fromsynergistic radar/lidar measurements
à Comparison with measured spectral radianceswith specMACS

Delanoë and Hogan (2008)

Ewald et al., 2021

à Good agreement of simulated andmeasured spectral radiance at 1900 nm
13WHAT CAN WE LEARN WITH CLOSURE
AND IN-SITU
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Coordinated HALO – FF20 - FAAM flight
Comparison with specMACS and in-situ measurements
NAWDEX RF06 – 14 October 2016

DLR HALO
Safire F20FAAM-BAE
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Comparison with specMACS

Ewald et al., 2021

NO agreement of simulated and measured spectral radiance at 1900 nm

16Comparison with specMACS

Ewald et al., 2021

NO agreement of simulated and measured spectral radiance at 1900 nm

17Analysis of multi-wavelength measurements
Comparison of Level1 measurements between HALO and FF20

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Analysis of multi-wavelength measurements
Comparison of Level2 data between HALO and FF20

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Analysis of multi-wavelength measurements
Comparison of Level2 data between HALO and FF20
Investigating the effects of different wavelengths on retrieved properties

Mie scattering / attenuation at 94 GHz leads to:- larger values of IWC- lower values of Reff
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AEROSOL CLASSIFICATION
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Aerosol type classification scheme
ICAROHS - ProjectMeasurement strategy

Aerosol classification

Linking optical andmicrophysical properties

Groß et al., 201322

A-CARE (DLR-Falcon (in-situ) + ground-based lidar)
April 2017
• Measurement side: Cyprus• Overflights over ground station in Cyprus and Crete: 2• Variable aerosol situation• Coordinated (ground-based) remote sensing and airborne
in-situ measurements

Objectives:- Analysis of airborne in-situ measurements- Analysis and quality control of ground-based remote sensing measurements and assessment for Level-2
processing- Relate microphysical properties measured in situ to the remote sensing data and refine the HETEAC modelaccordingly
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Aerosol type classification scheme
HETEC – Hybrid End-to-End Aerosol Classification
To connect microphysical, opticaland radiative properties of predefined aerosol components• Aerosol classification model
developed for EarthCARE andimplemented in ECSIM• 4 basic aerosol components withprescribed microphysicalproperties to calculate mixtures• Radiation closure for aerosol
from ATLID & MSI with BBR

Comparison of retrieved microphysical properties
with airborne in-situ measurements shows good agreement

Wandinger et al., 201624

Campaign gaps
Bringing together airborne measurements and the EC Level-2 algorithms• Use of the retrieved properties from airborne radar-lidar+... to simulate the measurementsfrom space. We can address multiple scattering for both radar and lidar (for example) and theimpact of the beam filling/geometry.
• Formatting our airborne data in order to be used by EC-processors
Airborne radar lidar measurements have been
rescaled to EarthCARE resolution but without
considering sensitivity for future space borne
measurements
à Use of existing and new data to performsensitivity studies
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Campaign gaps
• Radiative closure (active/passive – passive)
First closure studies show that under certain conditions microphysicalretrievals fail
à Perform more closure studies
à Test the use of additional information in microphysical retrievals(passive remote sensing measurements, Doppler measurements)• Ice microphysical properties used in retrieval
à Investigate the impact of used ice
microphysical properties
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