1. ADM-Aeolus and EarthCARE
ESA’s Earth Observation Lidar Missions
T. Wehr, P. Ingmann, A.G. Straume, A. Elfving, M. Eisinger, D. Lajas, A. Lefebvre, T. Fehr
European Space Agency
Second GALION Workshop
WMO Headquarters, Geneva, Switzerland
20-23 September 2010

2. ADM-Aeolus: The Atmospheric Dynamics Mission Aeolus
Main Objective
Measure wind profiles globally
Satellite
Polar sun-sync. orbit
Dawn-dusk
400km mean altitude
Launch: mid 2013
Payload
HSR Lidar at 355nm (ALADIN)

3. WHICH INFORMATION IS NEEDED BY GENERAL CIRCULATION MODELS (GCMS)?
When mass and wind fields are in approximate geostrophic balance, winds can be determined from temperature observations:
In the extra-tropics for large horizontal scales and for shallow structures
When geostrophic balance is not met, direct wind measurements are needed:
In the tropics
Globally for structures on small horizontal scales (e.g. around topography) and for deep vertical structures
Need for independent wind profile observations

4. WHY LAUNCH A SPACE-BASED DOPPLER WIND LIDAR?
Current Global Observing System (GOS)
Radiosonde - BUT NH continents dominate
Aircraft data - BUT NH densely populated areas dominate
Satellite soundings of temperature and humidity from Polar orbiting satellites BUT mass information, indirect measure of large-scale phenomenon wind outside the tropics through geostrophical balance
Atmospheric motion vectors - BUT only in the presence of clouds
Scatterometer winds – BUT only at the surface
Need for homogeneous global measurements of wind profiles

5. AEOLUS MEASUREMENT CONCEPT
(ALADIN)
(= height)
Wind and atmospheric optical properties profile measurements are derived from the Doppler shifted signals that are back-scattered by aerosols and molecules along the lidar line-
of-sight (LOS)

6. MEASUREMENT BASELINE Example of Aeolus vertical sampling
UV lidar (355 nm , circularly polarized)
Separate molecular and a particle backscatter receivers (High Spectral Resolution)
Line-of-sight points 35 deg from nadir and orthogonally to velocity direction to minimize contribution from satellite velocity
No polarization measurements
Adjustable vertical sampling of atmospheric layers with thicknesses from 0.25 – 2 km
Baseline change autumn 2010: Change from burst-to continuous mode operation.

7. Descending equatorial
ATMOSPHERIC PRODUCTS
Primary (L2b) product:
Horizontally projected LOS wind profiles
Approximately zonal at dawn/dusk
50 km averaged observations, 150 km spacing*
From surface to ~30 km
24 vertical layers per channel with thicknesses from 0.25 to 2 km
Accuracies: 2 (PBL), 2-3 (Trop), 3-5 (Strat) m/s
*Baseline change in 2010 will lead to longer observation lengths and removal (minimizing) of observation spacing
Spin-off (L2a) products:
Aerosol and cloud profiles, e.g.
, σ, OD
cloud cover/stratification, cloud top heights, cloud type
aerosol stratification, aerosol type
Dusk/dawn orbit
Courtesy
N. Žagar
Descending equatorial
crossing time: 6 AM

8. AEOLUS CLOUD AND AEROSOL PRODUCTS
Direct and indirect effect of aerosols partly compensate for global warming by greenhouse gases
Large uncertainties
Observations of aerosol properties are needed
ADM-Aeolus data on clouds and aerosol layers could be used directly by scientists for research on Atmospheric radiative budget and Water cycle applications
ADM-Aeolus data could be combined with contemporary data available from operational space based visible and infrared radiometers in order to derive higher level data products on clouds and aerosols

9. IMPACT OF SIMULATED AEOLUS WIND MEASRUREMENTS IN NWP
Main impact areas, as estimated by a Data Assimilation Ensemble at ECMWF:
Jet streams over the oceans
Above the oceans in the lower troposphere, e.g. western parts of the North Pacific and North Atlantic oceans, provided large enough cloud gaps
Tropics
Example of Aeolus wind profile impact in terms of 200 hPa (upper troposphere) zonal wind components (m/s)
Negative values: small ensemble spread -> positive observation impact
Courtesy D. Tan, ECMWF

10. HALO aircraft delivered to DLR in November 2008
ADM-AEOLUS CAMPAIGN ACTIVITIES
DLR further supports ADM-Aeolus activities in 2010 with
3 ground-based campaigns with the A2D, other lidars, windprofiler radar and radiosonde at DWD Lindenberg
2 airborne campaigns with Falcon or HALO aircraft with A2D and 2-µm wind lidar, co-located ground-based soundings
DLR Falcon 20 and HALO (High Altitude and Long Range Research Aircraft, modified Gulfstream G550) in April 2006
HALO aircraft delivered to DLR in November 2008
European Space Agency
ESA UNCLASSIFIED – For Official Use page 10

11. Areas covered by accepted projects (in total 16):
CAL/VAL ACTIVITIES
Call for Announcement of Opportunities (AOs) on Aeolus calibration and validation during its commissioning phase was issued 2007
Areas covered by accepted projects (in total 16):
Validation using ground-based, airborne and satellite experiments, providing independent measurements of wind profiles, clouds and aerosols;
Experiments to assess accuracy, resolution, and stability of the Aeolus laser instrument ALADIN;
Assessment and validation of the Aeolus retrieval and processing
Due to launch delay, a Delta CAL/VAL call is planned for early 2011

12. STATUS OF THE AEOLUS PROGRAM
The satellite and laser (ALADIN) subsystems have all been delivered and qualified on subsystem level
Structural and thermal qualification on platform (Aeolus) level has been performed with a Structure-Thermal Model
The transmitter laser is the most challenging for the qualification
The laser diode stacks have successfully completed their qualification testing
Amplifiers have successfully passed the first stability tests
All optical components of the transmitter laser and optical path have been qualified for the high intensities over the 3-year lifetime
Thermal vacuum qualification of the Power Laser Head is on-going
Scheduled launch: 2013

14. OVERVIEW The Earth Cloud, Aerosol and Radiation Explorer (EarthCARE)
is a satellite presently under development by the
European Space Agency ESA in cooperation with
the Japan Aerospace Exploration Agency JAXA
Payload
HSR Lidar at 355nm
W-Band (94GHz) Doppler Radar
Multi-spectral imager
Broad-band radiometer
Satellite
Polar sun-sync. orbit
13:45-14:00 desc. node
410km mean altitude
Launch: 2013

15. EARTHCARE SCIENCE OBJECTIVES
Quantify cloud-aerosol-radiation interactions so they may be included correctly in climate and numerical weather prediction models to provide:
Vertical distribution of atmospheric liquid water and ice on a global scale, their transport by clouds and radiative impact.
Cloud overlap in the vertical, cloud-precipitation interactions and the characteristics of vertical motion within clouds.
Vertical profiles of natural and anthropogenic aerosols on a global scale, their radiative properties and interaction with clouds.
The profiles of atmospheric radiative heating and cooling through a combination of retrieved aerosol and cloud properties.

16. Multi-spectral Imager
EARTHCARE MISSION CONCEPT
Needs
Techniques
EarthCARE
instruments
Radar
Lidar
CPR
ATLID
high sp. rs.
Aerosols: Vertical profiles of extinction and characteristics of aerosols
Clouds: Vertical profiles of liquid, supercooled and ice water, cloud overlap, particle size and extinction
Doppler Radar
CPR
Dopplerized
Vertical motion: Convective updraft and ice fall speed
Multi-spectral Imager
MSI
2-D Context: Clouds and aerosols horiz. structures
Broadband Radiometer
BBR
Radiation and Flux: Broad-band SW & TOA
Temperature and humidity from operational analysis

17. SYSTEM OVERVIEW Four instruments employed in synergy:
2 active: ATLID lidar + CPR radar  vertical cloud/aerosol profiles
2 passive: MSI imager + BBR radiometer  horizontal radiance fields
Stringent requirements for co-registration between instruments!
BBR
Industrial prime contractor: Astrium (D) 17

18. ATMOSPHERIC LIDAR (ATLID)
Backscatter UV (355nm) with high spectral resolution receiver, bistatic design
3 channels receiver: Rayleigh, co-polar Mie, cross-polar Mie (circ. pol., tbc) (separation Rayleigh-Mie by narrow bandwidth Fabry-Perot Etalon)  backscatter and extinction can be measured independently
Pulse repetition rate 74 Hz
Sampling: horizontal: 200m (=2x100m integrated), vertical: 100m
Receiver footprint on ground < 30 m
3 deg off-nadir (backwards) pointing to reduce specular reflection on ice clouds
Level 1 product: attenuated backscatter profiles
Built by Astrium (F),
with Selex Galileo (I)

19. CLOUD PROFILING RADAR (CPR)
High power W band (94GHz) nadir-pointing radar with Doppler capability
Antenna subtended aperture 2.5 m
Variable Pulse Repetition Frequency (PRF) Hz
Sensitivity at least 20km height
Sampling: horizontal: 500m, vertical 100m (vertical resolution 500m)
Beam footprint on ground < 800 m
Doppler accuracy 1 m/s (for 10 km along-track integration and -19dBZ)
Level 1 product: Reflectivity and Doppler profiles
Contribution of JAXA

20. MULTI-SPECTRAL IMAGER (MSI)
Nadir viewing push-broom imager
4 solar channels Vis (670nm), NIR (865nm), SWIR1&2 (1.65µm & 2.21µm)
3 TIR channels: 8.80µm, 10.80µm, 12.00µm
Swath: -35km to +115km (tilted away from sun to minimize sunglint)
Sampling (eff.): horizontal 500m x 500m
Calibration views: Sun, on-board warm blackbody, cold space
Level 1 product: Top-of atmosphere radiances and brightness temperatures in 7 spectral bands
Built by SSTL (UK), with TNO (NL)

21. BROAD-BAND RADIOMETER (BBR)
Short-wave (0.2µm-4µm) and total wave channel (0.2µm-50µm)
3 views: nadir, forward (+50°), backward (-50°)
Linear microbolometer array detectors, ground pixels < 1km x 1km
Rotating chopper wheel (261 rpm)
Calibration views: sun, internal cold and warm blackbodies
10km x 10km pixels spatially integrated in ground processing
Radiometric accuracy: 2.5 W/m2.sr (SW), 1.5 W/m2.sr (LW)
Level 1 product: Filtered top-of-atmosphere radiances short- and long-wave
Built by SEA (UK), with RAL (UK)

22. GEOPHYSICAL (LEVEL 2) PRODUCTS Single-Instrument Products (Level 2a)
CPR
Dopplerized Radar
feature mask
target classification
ice water content & effective radius
liquid water content & effective radius
vertical motion
precipitation / snow
ATLID
High spectr. res. Lidar
feature mask
target classification
extinction, back-scatter, depolarisation
aerosol extinction, backscatter, type
ice water content
MSI
Vis/NIR/SWIR/TIR
cloud flag / cloud type
cloud phase
cloud top temperature & height
Effective cloud particle radius
Aerosol optical thickness
BBR
Broad-band radiances
unfiltered solar radiance
unfiltered thermal radiance

23. 3-dim atmospheric scene construction
GEOPHYSICAL (LEVEL 2) PRODUCTS
Synergistic Products (Level 2b)
CPR
Dopplerized Radar
ATLID
High spectr. res. Lidar
MSI
Vis/NIR/SWIR/TIR
BBR
Broad-band radiances
Synergistic (variational scheme)
target classification
ice water content, eff. radius
liquid water content, eff. radius
aerosol extinction & type
rain water content, rain rate
cloud fraction & overlap
Synergistic
cloud top height
aerosol optical thickness
aerosol type
Angular Dependence
Models (ADM):
TOA LW flux
TOA SW flux
pixel size 10km x 10km
scene
classification
closure
assessment
3-dim atmospheric scene construction
pixel size 20km x 20km
1D & 3D-MonteCarlo radiative transfer modelling:
flux and heating rate profiles
TOA LW & SW radiances; LW & SW fluxes
pixel size 10km x 10km

24. LEVEL 2 ACTIVITIES Overall phasing
Scientific algorithm development  ATBD v1
2011 Processor implementation  ATBD v2
2012 ATBD peer review, processor consolidation
Ongoing ESA activities
QuARL Assimilation into ECMWF models (nearly completed)
ICAROHS Multi-wavelength HSRL aerosol retrievals
DAME Doppler radar
SITS Broad-band radiometer unfiltering
RATEC Radiative transfer models
IRMA MSI clouds and aerosols incl. ATLID synergy
ATLAS ATLID retrievals + synergistic target class.

25. ICAROHS – looking beyond EarthCARE
Overall phasing
Scientific algorithm development  ATBD v1
2011 Processor implementation  ATBD v2
2012 ATBD peer review, processor consolidation
Ongoing ESA activities
QuARL Assimilation into ECMWF models (nearly completed)
ICAROHS Multi-wavelength HSRL aerosol retrievals
DAME Doppler radar
SITS Broad-band radiometer unfiltering
RATEC Radiative transfer models
IRMA MSI clouds and aerosols incl. ATLID synergy
ATLAS ATLID retrievals + synergistic target class.
DLR Activity
Using DLR campaign data, such as SAMUM I & II and Eyjafjallajökull surveillance flights,
for the development and testing of geophysical retrieval algorithms for potential future multi-wavelength HSR lidars.
Integration as module into EarthCARE Simulator (ECSIM)

26. Radiative Transfer Calculation
SCIENCE DERIVED FROM EARTHCARE
The four instruments on board EarthCARE together:
(CPR: Cloud Profiling Doppler Radar ATLID: Lidar MSI: Imager BBR: Broad-band Radiometer)
Algorithms for these active sensors yield vertical profiles of microphysical parameters of cloud with its phase and aerosol with its species, and can detect drizzle and light rain.
Especially doppler velocities of particles can be retrieved to give us new information.
Parameters: vertical
cloud, aerosol,
drizzle, vertical motion
from active sensors
Model Use:
assimilation
validation
Model Improvement:
Cloud-Aerosol
interaction
EarthCARE
Parameters: horizontal
cloud, aerosol
from MSI
collaboration with Model
Cloud Scheme
Improvement
Climate Sensitivity
IPCC
Parameters: 3D
cloud, aerosol
Algorithm development
Scene Generator
&
Signal Simulator
Radiatve Transfer
&
3D Montecarlo
in cooperation with
Radiative Transfer Calculation
VS.
BBR data (True)
Radiative Flux:
BBR Data

27. MORE INFORMATION European Space Agency The Living Planet Programme
ADM-Aeolus
Mission Scientist: Paul Ingmann, ESA-ESTEC
EarthCARE
Mission Scientist: Tobias Wehr, ESA-ESTEC

28. Backup slides

29. MISSION IMPLEMENTATION
Baseline Technology
Direct detection UV lidar (355 nm) with Mie and Rayleigh receivers
Mie and Rayleigh receivers can sample the atmosphere with different altitude steps
The line-of-sight is pointing 35 deg from nadir orthogonal to the ground track velocity vector to minimize the Doppler contribution from satellite velocity
[H]LOS

30. MORE RECENT SCIENTIFIC STUDIES
The yield, accuracy and impact of simulated Aeolus data in an operational NWP set-up. Used an ensemble method (ECMWF)
Impact of Aeolus and alternative Aeolus sampling scenarios on predictive skills of Mid-latitudes high-impact weather systems (PIEW, KNMI)
Impact of the PIEW Aeolus sampling scenarios for the modelling of Tropical dynamics (Univ Ljubljana with KNMI, MISU for EUMETSAT)
Possible contribution to long-term database of cloud and aerosol optical properties; CALIPSO – Aeolus – EarthCARE (IfT and CNR-IMAA)
The impact of Rayleigh-Brillouin scattering on the lidar atmospheric backscattered signal (Univ Amsterdam with Nijmegen, Eindhoven)

31. FURTHER PRE-LAUNCH ACTIVITIES
Data processing: from Level 0 (raw data), Level 1B (calibrated wind profiles), Level 2A (cloud and aerosol products), Level 2B (scene classified temperature and pressure corrected wind profiles), to Level 2c (assimilated wind products)
Pre-launch campaigns
Vertical sampling strategy for various data applications (e.g. NWP vs. Stratospheric research)
The influence of Rayleigh-Brillouin scattering on lidar backscatter: Controlled laboratory experiments for the validation of the Tenti S6 model for air, for a set of representative T and p
Preparation of post-launch calibration and validation (CAL/VAL) activities

32. AEOLUS PRE-LAUNCH CAMPAIGNS BY DLR
1st and 2nd October 2006 and July 2007 with ALADIN airborne demonstrator (A2D)
Ground-based - Location: Lindenberg atmospheric observatory (DWD)
- Instruments: Radiosondes, wind profilers, wind and backscatter lidars, etc.
1st airborne November 2007
- Target area: Middle Europe and Mediterranean Sea
- Flights: 5 flights during 15 days with Falcon aircraft Payload: A2D and 2-µm wind lidar and flights over ground stations
2nd airborne December 2008
- Target area: Middle Europe and ocean
- Flights: 7 flights during 11 days with Falcon aircraft Payload: A2D and 2-µm wind lidar and flights over ground stations
3rd airborne September 2009
- Target area: North-West Atlantic
- Flights: 4-5 flights during 18 days with Falcon aircraft
- Payload: A2D and 2-µm wind lidar