NASA GSFC Elastic Backscatter Lidar Efforts Relevant toEarthCARE Calibration/Validation and Synergistic Data
Products
Ed Nowottnick – NASA Goddard Space Flight Centerwith contributions from:John Yorks (NASA GSFC), Kenny Christian (NASA GSFC/ESSIC), Patrick Selmer (NASA GSFC/SSAI),
Natalie Midzak (U. North Dakota), Joe Finlon (NASA GSFC/ESSIC), Alex Matus (NASA GSFC/NPP)
EarthCARE Science and Validation Workshop
November 16, 2023

Airborne Lidar Suite at GSFC
Since 1999 multiple
autonomous instruments havebeen built by our lidar group at
GSFC photon-counting/high
rep-rate designs
Designed primarily for NASAhigh-altitude aircraft (ER-2,WB-57, Global Hawk) – now
Gulfstreams as well
Utilize high repetition rate,
photon counting technique
Led to the development of theCloud Aerosol Transport
System (CATS) technology
demonstration on theISS(2015-2017) and ALICATfor AOSCPL Instrument Overview
Instrument Characteristics:
••
•
•
•

3 Wavelengths: 1064, 532, and 355 nm
Depolarization using 1064 channel
Fully autonomous
Near nadir pointing
Small FOV minimizes multiplescattering• Resolution: 30 m (vert), 200 m (hor)Two duplicate instruments:1. Built for high-altitude aircraft(ER-2)••

Flight altitude of about 20-km
Measure full troposphere

2. Deployed on low-flying aircraft••

Primarily for aerosol/PBL on C-130,
Gulfstreams
Being converted to ER-2 backup

Wavelengths
Laser type
Laser repetition rate
Laser output energy
Telescope
Telescope FOV

1064, 532, 355 nm
solid state Nd:YVO45 kHz
50 mJ at 1064 nm
25 mJ at 532 nm
50 mJ at 355 nm
20 cm diameter
100 mradians, full angle

What’s new with CPL?
Integrated on G-III

Real-Time Data Products• CPL flew on the NASA G-III (LaRC) in the summer of 2021 as part ofthe Michigan-Ontario Ozone Source Experiment• CPL now employs a Jetson TX-2 GPU that applies signal denoisingand convolutional neural network techniques developed on CATS
data described in Yorks et al., 2021 for real time data products• As part of review process, also cleared to fly on the NASA G-V (JSC)• Provides data in real time for flight plan adjustments/coordination

350 m

Raw Data

Denoised Raw Data
60 km

Feature Classification
350 m

What’s Roscoe?
• Roscoe is a new airborne lidar that has heritage from
GSFC’s Cloud Physics Lidar (CPL)• What’s the difference?
• CPL – Downward looking with attenuatedbackscatter measurements at 355, 532, and 1064
nm with polarization sensitivity at 1064 nm• Roscoe – Upward and downward looking
attenuated backscatter measurements at 355 and1064 nm with polarization sensitivity in all
wavelengths and directions. Enables UTLS
aerosol/cloud measurements while mitigating eye
safety concerns (no visible).
• Provides the same data and real-time products as CPL• The 2021 ACCLIP Test Flights were the first forRoscoe on the WB-57. Engineering flights on the ER-2
were performed pre-pandemic.

Maiden Test Flights Along with CPL on the ER-2

First test flights on the ER-2 in October 2019
Roscoe 1064 nm [km-1 sr-1]

CPL 1064 nm [km-1 sr-1]

12 km

12 km

8 km

8 km

0.05

0.025

4 km

4 km

0 km

0 km

0.00

ACCLIP and SABRE Results•

Participated in SABRE test flights (Feb2022) and ACCLIP Field Campaign(summer 2022)•Existing CPL processing algorithms
working well with Roscoe data•

Still refining the feature typingalgorithm but successful first series ofcampaigns

More ACCLIP Results• Great opportunities to test the upward and downward channels• Enables lidar measurements on single airborne platform deployments that utilize both remote sensing andin situ instruments

Beyond Airborne Work – ALICAT for AOS
Atmospheric Lidar Instrument for Clouds and Aerosol Transport (ALICAT):

2019
PolarOrbiting
DiurnalSampling•

Provides vertical profiles of total and perpendicular attenuated backscatter at
532 and 1064 nm to identify clouds, aerosols, as well as their phase and type•

Provides a new opportunity for synergistic products in an inclined orbit (e.g. Ku
radar+radiometer+lidar products) not possible with CALIPSO or CATS•Will deliver near-real time (<6 hours) data products to the applicationscommunity•Leverages 20 years of lidar instrument heritage at NASA GSFC, including theCloud Aerosol Transport System (CATS) that flew on the ISS from 2015-2017 –building and testing it now•Offers early science delivery for AOS by launching later this decade (2029)

2023

2027

2031

AOS-Sky LidarAeolus II

CloudSat/CALIPSOGPMINCUSAOS-StormAOS Science Addressed by ALICATAOS is a process-focused mission with lidars and radars as centerpieces to provide xvertical measurements ofaerosols, clouds, and precipitation – and their diurnal variability
Objective 2: High Clouds
Measurements of thin high clouds,
especially in the presence of convection

Objective 3: Convective Storms
Detection of environmental aerosolsin the presence of convection

Objective 5: Aerosol Attribution/Air-Quality
Measurements of optically thick dust, smoke,and anthropogenic aerosols in source regions
above and within the PBL
Objective 6: Aerosol Removal & Redistribution
Synergistic observations of aerosols andconvective precipitation/vertical motions

DustSmoke

ALICAT Science: Cirrus Clouds• CALIPSO has provided cloudmeasurements for 17 years in asun-sync orbit• CATS provided diurnal
measurements of clouds with asingle wavelength, but was a techdemo without science
requirements• ALICAT offers improved SNR
compared to CATS and an
opportunity to provide CALIPSO
quality measurements with an
added time dimension in anaffordable package• AOS-Storm matches ALICAT withmicrowave radiometers and a Ku
radar for diurnal sampling ofconvective processes

CALIPSO Cirrus Validation of Cloud
Measurements using Airborne CPL

Hlavka et al., 2012

Diurnal Cycle of Clouds
Observed by CATS Tech Demo(2015-2017)

Noel et al., 2018

ALICAT Science: Aerosols• Dust and smoke aerosols exhibit diurnal cycles thattypically correspond to enhanced burning during
daytime hours*• Smoke interacts with the evolution of the planetary
boundary layer and has implications for the diurnal cycleof convection** - important for smoke transport
forecasting in current models***

CATS V3 2015-2017

01:30
13:30
Daily Range
16-19:00 Range

Smoke from Oregon: Implications for Transport and Air
Quality Observed by CATSCALIPSO V4.20 2015-2017* Hyer et al., 2013** Zhang and Zuidema, 2019; Hodzik and Duvell, 2017*** Ye et al., 2021

Diurnal Variability of Smoke
Aerosols Observed by
CATS over Borneo

Opportunities for Future Collaboration
Airborne:• Planned NASA ER-2 mission using CPL in the fall 2024 out of Palmdale,
California – underpasses of EarthCARE?
• UTLS aerosol detection validation using Roscoe• Future NASA EVS-4 opportunities (TBD) or joint field campaign activities(e.g. CPEX-AW; CPEX-CV)
Spaceborne:• Leverage aerosol typing from ATLID and any planned validation efforts tohelp inform lidar ratio selection for ALICAT – more robust than simple
algorithms that rely on ancillary information despite differences inwavelengthThanks!

Contact:
edward.p.nowottnick@nasa.gov

BackupALICAT Daytime Performance
ALICAT daytime 532 nm ATB (bottom) will have improved SNR compared to CATS
and CALIOP (middle)

CPL data from the NASA ER-2 aircraft (top panel) and CALIOP (middle panel)
during a validation flight on 18 August 2015 over the western US. ALICAT ATB(bottom) simulated for day using the airborne lidar data as input.

IMPACTS EVS-3 Field Deployment (2020-2023)
Deployments: Jan– Feb 2020, 2022, 2023
Aircraft on station time: 4 – 6 hours

Conducted 33
flights and over150+ hours (21coordinated flights)
in 2020-2023 duringstrong winterstorms, weakerstorms, andclippers.

29 JanCloud Phase & Habit Type using CPL during IMPACTS

Temp

Hierarchical clustering technique to enable finer cloud particle phase/type classifications with improved
vertical resolution and create a training dataset for a CNN model
Uses BSL depol. ratio, temperature, and altitude of each bin• 5 clusters ofCurrent cloud phase algorithms classify
potential particle
phase on a cloud “layer” basis for eachphases/types:
profilecolumn aggregates, • This does NOT capture the verticalvariability within a cloudplate aggregates,• Clustering technique DOES capture thisirregular/other ice,vertical variability
SCLW, warm liquidwater (C, right)
Cloud Top Phase w/ BSLCold• Particle
Columns
phases/types areHOIRosettes
assigned based onMixed
Phase
literature and/orPlates
SCLW
Noel et al. (2004) &collocated in situ
Spheriods Lawson et al. (2006)
data from P-30C
Liquidaircraft during
Water
Cloud
IMPACTS field
Dust Aerosols
Warmcampaign flights.
Ongoing work at NASA GSFC (Joe Finlon)
0.0
0.6
Depol

Improved Constrained Retrievals of Extinction
Signal Loss Method for Aerosol Layers

Constraints from Geostationary AOD• Technique is traditionally restricted to clouds• Uses the AOD from a passive aerosol sensor (i.e.,MODIS, VIIRS, ABI, etc.) to retrieve a layer-average
lidar ratio and thus more accurate extinction profile.

•Results in an iterative, best-fit solution to measured
two-way transmittance loss of signal through atransparent layer• Midzak et al. (2022) shows errors <25%

• Integrated attenuated total backscatter is comparedto the estimated integrated molecular signal in theclear air zone to calculate layer transmission
Williams Flats Fire

Signal Loss Method
GOES Constrained
Unconstrained

CPL overpass of Williams Flats
Fire on 08 August was collocatedwith GOES-R
AOD values from both sensors
compare well

Courtesy ofNatalie Midzak (UND)

Midzak et al. 2022 [Frontiers]•

GOES: 0.59±0.09•

CPL constrained: 0.59±0.66•

CPL unconstrained: 0.81±0.62