EarthCARE Calibration and Validation
Using an Airborne HSRL

Chris Hostetler
Johnathan Hair
Richard Ferrare
Sharon Burton
NASA Langley Research Center (LaRC)
Presented at the ESA-JAXA Pre-Launch EarthCARE
Science and Validation Workshop
13-17 November 2023

NASA Langley (LaRC) HSRL team participation in ATLID validation focuses on theuse of HSRL-2 measurements
 HSRL-2 is LaRC’s second-generation airborne
HSRL– 3β + 2α + 3δ aerosol/cloud lidar• HSRL capability at 355 and 532 nm• Elastic backscatter lidar capabilty at 1064 nm• Polarization sensitive at 355, 532, and 1064 nm– Ozone DIAL capability– Ocean profiling capability (1-m depth resolution)• Particulate backscatter (355 and 532 nm)• Diffuse attenuation coefficient (355 and 532 nm)• CDOM fluorescence• Chlorophyll fluorescence2>150 CALIPSO validation flights with
HSRL-1 and HSRL-2

 Flown on 16 field deployments starting in 2012
 Aircraft: King Air, G-III, G-V, P3, ER-2
 Often deploys with one or more passive remotesensors, especially polarimeters andspectroradiometers

HSRL-2 measurements are relevant to ATLID validation in several ways
 355-nm measurements provide
direct validation of ATLID Level-2products
 Coincident 532- and 1064-nm
measurements provide a bridge data
set for interpretation of validation
measurements made from
instruments without 355-nm
capability– Ground-based and airborne– Statistical comparisons with CALIPSO

 Higher information content provides
means to assess ATLID aerosoltyping

Example Level 1 validation
4/22/2010[km-1sr-1]

CALIPSO[km-1sr-1]

HSRL

bias =0.7%

Example Level 2 aerosol profile validation (v3.01)

CALIPSO

HSRLValidation assessment of CALIPSO extinction and lidar ratio assumption
 CALIPSO extinction retrieval relies on an assumptionof lidar ratio
 Lidar ratio assumption is based on CALIPSO inferenceof aerosol type
 CALIPSO uses a discrete set of lidar ratios
 Airborne HSRL used to assess extinction value as wellas underlying aerosol type and lidar ratio assumption

Rogers et al. (2014), Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth usingairborne high spectral resolution lidar data. AMT

HSRL-2 high information content (3β + 2α + 3δ) useful for assessing HETEAC aerosol typing andwavelength dependencies to connect 355-nm ATLID measurements to 532/1064-nm data sets

Burton et al. (2013), Aerosol classification fromairborne HSRL and comparisons with the CALIPSO
vertical feature mask, AMTBurton, S. P., et al. (2015), Observations of thespectral dependence of linear particle depolarization
ratio of aerosols using NASA Langley airborne HighSpectral Resolution Lidar, ACPLaRC HSRL team proposal objectives
1. Participate in EarthCare Cal/Val Team planning efforts and development of the ACPV bestpractices document
2. Work with the EarthCare Team in the use of existing airborne HSRL-2 data in thedevelopment and assessment of ATLID retrieval algorithms
3. Develop and implement a methodology for assessing ATLID Level-1b data products–HSRL-2 operational processing includes no Level-1b step. This will require development of a newproduct and associated uncertainties

4. Use the extensive set of airborne HSRL-2 measurements to develop a “translation
database” for––Relating ATLID measurements at 355 nm to CALIOP and other lidar measurements acquired at 532 nm
and 1064 nm
Assessing ATLID’s HETEAC aerosol typing skill and comparing to aerosol typing using otherwavelengths

5. Use HSRL-2 data to evaluate selected ATLID L1 and L2 aerosol and cloud products fromfuture airborne underflights

LaRC HSRL team funded proposal objectives
1. Participate in EarthCare Cal/Val Team planning efforts and development of the ACPV bestpractices document
2. Work with the EarthCare Team in the use of existing airborne HSRL-2 data in thedevelopment and assessment of ATLID retrieval algorithms
3. Develop and implement a methodology for assessing ATLID Level-1b data products–HSRL-2 operational processing includes no Level-1b step. This will require development of a newproduct and associated uncertainties

4. Use the extensive set of airborne HSRL-2 measurements to develop a “translationdatabase” for––Relating ATLID measurements at 355 nm to CALIOP and other lidar measurements acquired at 532 nm
and 1064 nm
Assessing ATLID’s HETEAC aerosol typing skill and comparing to aerosol typing using otherwavelengths

5. Use HSRL-2 data to evaluate selected ATLID L1 and L2 aerosol and cloud products fromfuture airborne underflights

Validation-relevant data sets
 First validation underflight opportunity will be during the PACE-PAX campaign (Sept 2024).
– Focus is validation of the aerosol/cloud products from the PACE mission– Deploy on the NASA ER-2; flight level ~ 19 km– See Kirk Knobespiesse’s presentation for details

 Anticipate that NASA will fund more validation underflights in the future. We are eager towork with ESA and NASA HQ to define future underflight opportunities.
 Past data sets may be used by members of the EarthCARE validation community to– Explore translation of 532-nm airborne and ground-based validation data to ATLID’s 355-nm products– Assess HETEAC aerosol typing– Explore active-passive synergy retrievals–…

We look forward to working with the EarthCARE
validation team!