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

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)

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

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

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)

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.

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

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

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

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 www.halo.dlr.de European Space Agency ESA UNCLASSIFIED – For Official Use page 10

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

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

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

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.

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 & LW @ TOA Temperature and humidity from operational analysis

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

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)

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) 6100-7500 Hz Sensitivity at least -35dBZ @ 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

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)

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)

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

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

LEVEL 2 ACTIVITIES Overall phasing 2009-10 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.

ICAROHS – looking beyond EarthCARE Overall phasing 2009-10 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)

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

MORE INFORMATION European Space Agency The Living Planet Programme http://www.esa.int/esaLP/index.html E-mail: living.planet@esa.int ADM-Aeolus Mission Scientist: Paul Ingmann, ESA-ESTEC EarthCARE Mission Scientist: Tobias Wehr, ESA-ESTEC

Backup slides

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

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)

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

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