Displays

The European Space Agency (ESA)’s wind mission, Aeolus, was launched on 22 August 2018. Aeolus is a member of the ESA Earth Explorer family and its main objective is to demonstrate the potential of Doppler wind Lidars in space for improving weather forecast and to understand the role of atmospheric dynamics in climate variability. Aeolus carries a single instrument called ALADIN: a high sophisticated spectral resolution Doppler wind Lidar which operates at 355 which is the first of its kind to be flown in space. It provides profiles of single horizontal line-of-sight winds (primary product) in near-real-time (NRT), and profiles of atmospheric backscatter and extinction. The instrument samples the atmosphere from about 30 km down to the Earth’s surface, or down to optically thick clouds. The required precision of the wind observations is 1-2.5 m/s in the troposphere and 3-5 m/s in the stratosphere while the systematic error requirement be less than 0.7 m/s. The mission spin-off product includes information about aerosol and cloud layers. The satellite flies in a polar dusk/dawn orbit (6 am/pm local time), providing ~16 orbits per 24 hours with an orbit repeat cycle of 7 days. Global scientific payload data acquisition is guaranteed with the combined usage of Svalbard and Troll X-band receiving stations.

The status of the Aeolus mission will be provided, including its performance assessment, planned operations and exploitation in the near future. This comprises the outcome of the instrument in its early operation phase, calibration and validation activities and a general review of the main scientific findings. Scope of the paper is also to inform about the programmatic highlights and future challenges.

How to cite: Parrinello, T., Straume, A. G., Von Bismark, J., Bley, S., Tran, V. D., Fischer, P., Kanitz, T., Wernham, D., Fehr, T., Alvarez, E., Reitebuch, O., and Krisch, I.: Aeolus: ESA’s wind mission. Status and future challenges , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4091, https://doi.org/10.5194/egusphere-egu2020-4091, 2020.

The European Space Agency (ESA)’s Earth Explorer Aeolus was launched in August 2018 carrying the world’s first spaceborne wind lidar, the Atmospheric Laser Doppler Instrument (ALADIN). ALADIN uses a high spectral resolution Doppler wind lidar operating at 355nm to measure profiles of line-of-sight wind components in near-real-time (NRT). ALADIN samples the atmosphere from 30km altitude down to the Earth’s surface or to the level where the lidar signal is attenuated by optically thick clouds.

The global wind profiles provided by ALADIN help to improve weather forecasting and the understanding of atmospheric dynamics as they fill observational gaps in vertically resolved wind profiles mainly in the tropics,  southern hemisphere, and over the northern hemisphere oceans. In January 2020, the European Centre for Medium-Range Weather Forecasts (ECMWF) became the first numerical weather prediction (NWP) centre to assimilate Aeolus observations for operational forecasting.

A main prerequisite for beneficial impact is data of sufficient quality. Such high data quality has been achieved through close collaboration of all involved parties within the Aeolus Data Innovation and Science Cluster (DISC), which was established after launch to study and improve the data quality of Aeolus products. The tasks of the Aeolus DISC include the instrument and platform monitoring, calibration, characterization, retrieval algorithm refinement, processor evolution, quality monitoring, product validation, and impact assessment for NWP.

The achievements of the Aeolus DISC for the NRT data quality and the current status of Aeolus wind measurements will be described and summarized. Further, an outlook on future improvements and the availability of reprocessed datasets with enhanced data quality will be provided.

How to cite: Krisch, I. and the Aeolus DISC: Data quality of Aeolus wind measurements, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9471, https://doi.org/10.5194/egusphere-egu2020-9471, 2020.

The European Space Agency’s Aeolus mission, which was launched in August 2018, provides profiles of horizontal line-of-sight (HLOS) wind observations from a polar orbiting satellite.  The European Centre For Medium-Range Weather Forecasts (ECMWF) began the operational assimilation of Aeolus Level-2B winds on 9 January 2020 in their global NWP (Numerical Weather Prediction) model, 1 year and 4 months after the first Level-2B wind products were produced in near real time via ESA’s ground processing segment.  This achievement was possible because of the production of good data quality, which was met through a close collaboration of all the parties involved within the Aeolus Data Innovation and Science Cluster (DISC) and via the great efforts of ESA, industry and ground processing algorithms pre- and post-launch.
Through the careful assessment of the statistics of differences of the Aeolus winds relative to the ECMWF model, the Level-2B Rayleigh winds were found to have large systematic errors.  The systematic errors were found to be highly correlated with ALADIN’s (Atmospheric Laser Doppler Instrument) primary mirror temperatures, which vary in a complex manner due to the variation in Earthshine and thermal control of the mirror.  The correction of this source of bias in the ground processing is underway, therefore in the meantime a bias correction scheme using the ECMWF model as a reference was developed for successful data assimilation; the scheme will be described.  
We will present the results of the Aeolus NWP impact assessment which led to the decision to go operational.  Aeolus’ second laser (FM-B, available since late June 2019) provides statistically significant positive impact of moderate to large amplitude, of similar magnitude to some other important and well-established observing systems (such as IR radiances, GNNS radio occultation and Atmospheric Motion Vectors).  Observing System Experiments demonstrate reduction of forecast errors in geopotential and vector wind of around 2% in the tropics and 2-3% in the southern hemisphere for short-range and medium range forecasts (up to day 10).  This positive impact is particularly impressive given that Aeolus provides less than 1% of the total number of observations assimilated, showing the value of direct wind observations for global NWP.

How to cite: Rennie, M. P. and Isaksen, L.: An Assessment of the Impact of Aeolus Doppler Wind Lidar Observations for Use in Numerical Weather Prediction at ECMWF, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5340, https://doi.org/10.5194/egusphere-egu2020-5340, 2020.

After much anticipation and several years of delay the ALADIN lidar was launched on the Aeolus platform in August 2018. ALADIN is the world’s first space-based Doppler lidar. It operates at 355nm and its main products are line-of-sight winds. Wind-profiles are derived from the Doppler shift of the backscattered signals. Using a variation of the High Spectral Resolution Lidar technique (HSRL), two detection channels are used, a `Mie ‘-channel and a `Rayleigh’-channel. Cloud/aerosol information is also present in the signals, however, ALADIN’s design is optimized for wind observations and the retrieval of aerosol/cloud products is secondary (but important for various applications, e.g. the monitoring of atmospheric composition).

While cloud and aerosol products are secondary products for ALADIN, they are primary products for the EarthCARE lidar ATLID. EarthCARE stands for the Earth Clouds Aerosol and Radiation Explorer and is a joint ESA-JAXA multi-instrument cloud-aerosol-precipitation primarily process study oriented mission planned to be launched in 2022 EarthCARE will embark a lidar called ATLID. ATLID, like ALADIN is a 355 nm HSRL system, but is optimized for cloud/aerosol measurements. Compared to ALADIN, ATLID has a higher spatial resolution, measures the depolarization of the return signal and has a much cleaner Rayleigh- Mie backscatter signal separation. Like ALADIN though, the SNR makes accurate retrievals a challenge. Over the past several years, a suite of cloud/aerosol algorithms have been developed for ATLID that have focused on the challenge of making accurate retrievals of cloud and aerosol extinction and backscatter specifically addressing the low SNR nature of the lidar signals and the need for intelligent binning/averaging of the data. These ATLID approaches have reached a certain stage of maturity; however, they have been tested using mainly simulated data with the aid of the ECSIM multi-instrument end-to-end simulator.

The lessons learned by the application of ATLID-like algorithms on ALADIN data would lead to better ATLID products when it is launched. Further, preliminary work indicates that AT LID-inspired techniques can be successfully adapted to ALADIN measurements and have the potential to lead to improvements in the ALADIN extinction and backscatter products. In this presentation, ATLID-like approaches for ALADIN feature detection and extinction and lidar-ratio retrieval (based on an optimal-estimation approach) will be described. Examples will be presented and compared with observations made using ground-based lidars.

How to cite: Donovan, D., van Zadelhoff, G.-J., Flament, T., Trapon, D., and Baars, H.: The application of ATLID techniques for aerosol/cloud retrievals to ALADIN, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13805, https://doi.org/10.5194/egusphere-egu2020-13805, 2020.

Since 2007, a series of ESA supported airborne campaigns have been essential to the development of the Aeolus Doppler Wind Lidar satellite mission, which was successfully launched on 22 September 2018 and is providing a novel wind and aerosol profile data.

A core element of the Aeolus Cal/Val activities is DLR’s A2D wind lidar on-board the DLR Falcon aircraft, an airborne demonstrator for the Aeolus ALADIN satellite instrument flown in combination with the 2-µm Doppler Wind Lidar reference system. Following the pre-launch WindVal-I and –II campaigns in 2015 and 2016, a number of calibration and validation campaigns have been successfully implemented: WindVal-III providing early Cal/Val results in November 2018 only three months after the Aeolus launch, AVATAR-E in May 2019 focussing on the Cal/Val over Central Europe, and AVATAR-I in September 2019 providing Cal/Val information in the North Atlantic and Arctic flying from Iceland.

The airborne validation is also being supported through balloon flights in the tropical UTLS and lower stratosphere in the frame of the CNES Stratéole-2 stratospheric balloon activities. In the frame of the ESA supported pre-Stratéole-2 campaign, eight stratospheric balloons have been launched from the Seychelles in November/December 2019 providing unique upper level wind data for the Aeolus validation.

The largest impact of the Aeolus observations is expected in the Tropics, and in particular over the Tropical oceans, where only a limited number of wind profile information is provided by ground based observations. Aeolus provides key direct measurements which are of importance to correctly constrain the wind fields in models. In addition, Aeolus observations have the potential to further enhance our current knowledge on aerosols and clouds by globally providing optical properties products that include atmospheric backscatter and extinction coefficient profiles, lidar ratio profiles and scene classification. In the tropics, a particularly interesting case is the outflow of Saharan dust and its impact on micro-physics in tropical cloud systems. The region off the coast of West Africa allows the study of the Saharan Aerosol layer, African Easterly Waves and Jets, Tropical Easterly Jet, as well as the deep convection in ITCZ. 

Together with international partners, ESA is currently implementing a Tropical campaign in July 2020 with its base in Cape Verde that comprises both airborne and ground-based activities addressing the tropical winds and aerosol validation, as well as science objectives. The airborne component includes the DLR Falcon-20 carrying the A2D and 2-µm Doppler Wind lidars, the NASA P-3 Orion with the DAWN and HALO lidar systems, the APR Ku-, Ka- and W-band Doppler radar and drop sondes, and a Slovenian small aircraft providing in-situ information from aethalometers, nephelometers and optical particle counters. The ground-based component led by the National Observatory of Athens is a collaboration of European teams providing aerosol and cloud measurements with a range of lidar, radar and radiometer systems, as well as a drone providing in-situ aerosol observations. In addition, the participation airborne capabilities by NOAA and LATMOS/Meteo France are currently being investigated.

This paper will provide a summary of the Aeolus campaign focussing on the planned tropical

How to cite: Fehr, T., Amiridis, V., Bley, S., Cocquerez, P., Lemmerz, C., Močnik, G., Skofronick-Jackson, G., and Straume, A. G.: Aeolus Calibration, Validation and Science Campaigns , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19778, https://doi.org/10.5194/egusphere-egu2020-19778, 2020.

In January 2020, the European Centre for Medium-Range Weather Forecast (ECMWF) became the first numerical weather prediction (NWP) centre to assimilate wind observations from the new European Space Agency (ESA)’s Earth Explorer satellite Aeolus for operational forecasting. Aeolus was launched into space on August 22^nd, 2018, carrying the world’s first spaceborne wind lidar, the Atmospheric Laser Doppler Instrument (ALADIN). ALADIN measures profiles of line-of-sight wind components from 30km altitude down to the Earth’s surface or to the level where the lidar signal is attenuated by optically thick clouds.

Impact assessment studies performed at ECMWF in 2019, show improved weather forecasting skills, by assimilating Aeolus wind measurements. As a side effect, these impact experiments also reveal an influence of Aeolus data assimilation on the representation of resolved gravity waves in the ECMWF model fields. Both, orographic and non-orographic gravity waves are impacted by the Aeolus data assimilation.

This impact of Aeolus data assimilation on the representation of gravity waves in ECMWF will be presented for selected case studies in the southern hemisphere. Ground-based and airborne measurement data from the SOUTHTRAC campaign will be used for validation where available.

How to cite: Krisch, I., Rennie, M., Kaifler, B., Gisinger, S., Reitebuch, O., and Rapp, M.: Influence of Aeolus data assimilation on the representation of gravity waves in ECMWF analysis fields, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9546, https://doi.org/10.5194/egusphere-egu2020-9546, 2020.

The ESA Earth Explorer mission Aeolus partly fulfills the well-expressed need for wind profile observations to initialize Numerical Weather Prediction (NWP) models. Aeolus has proven beneficial in particular over regions void of wind profile observations in the troposphere and lower stratosphere, particularly over the oceans, tropics and southern hemisphere. Although successful, Aeolus only partly fills the data gap following the requirements on data coverage, data quality and timeliness. These requirements are generally well captured by the World Meteorological Organization (WMO) Observing Systems Capability Analysis and Review (OSCAR) and Rolling Requirements Review (RRR).

With the success of Aeolus the moment has come to look forward to future vertical wind profiling capability to fulfil the rolling requirements in operational meteorology. Already in 2005 ESA initiated a study on potential Aeolus follow-on missions. Options studied included an Aeolus type instrument, but measuring profiles of the complete wind vector, rather than a single wind component like Aeolus. In addition, the benefits of a constellation of a number of Aeolus instruments was studied. It was shown that given a fixed number of observations doubling the coverage of single wind components, through the positioning of two Aeolus satellites in the same orbit, is more beneficial for NWP than a single satellite measuring the complete wind vector. A third Aeolus-type satellite in the same orbit further adds to NWP, although first indications of impact saturation emerged when distributing more satellites in the same sun-synchronous orbit.

This paper provides an overview of the methodology used to assess the potential impact of Aeolus follow-on missions and first conclusions on optimal wind profile sampling for NWP in the context of the WMO RRR.

How to cite: Marseille, G.-J. and Stoffelen, A.: Aeolus follow-on configurations, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20758, https://doi.org/10.5194/egusphere-egu2020-20758, 2020.

After about 1.5 years in operations, the Aeolus Ground Segment is performing very well for all core functions including X-band data acquisition, mission planning, systematic science data production in Near Real Time, data access, data archival and thus continues to secure successfully important operational mission objectives.

Aeolus Payload Ground Segment operations are implemented through a set of service contracts that are either based on a full service approach, e.g. for payload data acquisition, or on a delegated service approach as for systematic data production and mission planning, in which ground segment components specifically developed for Aeolus mission are operated. The Services performances are agreed and measured through service level agreements.

Global scientific payload data acquisition is guaranteed by KSAT with the combined usage of Svalbard and Troll X-band receiving stations. Level-2B and Level-2C products are systematically generated at ECMWF, European Centre for Medium-Range Weather Forecasts.

The current performances of the overall Aeolus ground segment will be provided, including its operations and planned evolution in the near future.

How to cite: Fischer, P., Mellano, L., De Laurentis, M., Aprile, S., and Biscuso, A.: Aeolus: Payload Ground segment operations. Status, performances and evolution , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9226, https://doi.org/10.5194/egusphere-egu2020-9226, 2020.

Launched in August 2018, Aeolus is the first remote sensing mission using a Doppler Wind Lidar for the observation of Earth’s wind and air circulation on a global scale. The main instrument ALADIN – Atmospheric LAser Doppler INstrument –  is measuring the atmospheric dynamics in the near-UV at wavelength of 355 nm, receiving back the signal through two different channels for clear air molecules (Rayleigh) and aerosol and clouds particles (Mie).

ALADIN operations are commanded from ground and are a combination of wind acquisitions and in-flight calibrations, for monitoring the instrument health and improving data quality. The mission is based on a planning cycle of 111 orbits, covering exactly one calendar week, for ~16 orbits per day.

The analysis of the weekly mission planning is performed taking into account a number of requirements and constraints at different levels, including platform and instrument system requirements, calibrations measurement performance, NRT data optimisation, science and cal/val requests, and requirements in support to collocated measurement campaigns. Once the analysis is done, the planning is then built into a timeline of consecutive requests for changing measurement mode, using specific instrument parameters tables.

This poster will provide an overview of the Aeolus weekly mission planning concept, strategy and methodology, together with a description of the major operations events for Aladin FM-A and FM-B instruments during the operational phase.

How to cite: De Laurentis, M., Fischer, P., Mizzi, L., and Mellano, L.: AEOLUS weekly mission planning concept and strategy, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13908, https://doi.org/10.5194/egusphere-egu2020-13908, 2020.

VirES (Virtual Workspace for Earth Observation Scientists) is a highly interactive data manipulation and retrieval interface for specific ESA Earth Explorer mission products. It is under evolutionary/operational maintenance by EOX since 2016 for the Swarm geomagnetic mission and starting 2018 it has been extended for ESA's Earth Explorer Aeolus wind profiling mission.

The goal of this service is to provide users with intuitive and easy access to the mission’s level 1B, 2A, 2B and several auxiliary data products.
In order to be able to understand, manage, visualize and analyze the new and complex data produced by the satellite a close collaboration between project partners DLR and DoRIT and EOX as industry partner has been established.

VirES for Aeolus provides means for multi-dimensional visualization, interactive plotting and analysis and stands for a modern concept of extended access to Earth Observation (EO) data. It supports novel ways of data discovery, visualization, filtering, selection, analysis, snapshotting and downloading.

The service was designed with a focus on the following areas of application:
Quality analysis, calibration and validation, scientific exploitation, modeling and prediction.

Specialized solutions have been developed to allow visualization of the complex and large datasets in an interactive and intuitive way. The tool has been further refined and improved since the Aeolus launch August 2018 in close collaboration with its users and project partners. VirES for Aeolus  offers easy access to the mission data through ordinary web browsers  via without the need for installing any specialized software.

How to cite: Santillan, D., Schiller, C., Meringer, M., Reitebuch, O., Weiler, F., and Huber, D.: VirES for Aeolus - Online visual analysis of Aeolus data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22439, https://doi.org/10.5194/egusphere-egu2020-22439, 2020.

We present the methodology and results of the Aeolus VC01 and L0 FM-A and FM-B datasets consolidation performed by the X-PReSS team as part of the ESA (European Space Agency) Data Service Initiative (DSI) managed by ESA’s Ground Segment Operations Division. The goal of this activity is to generate master datasets and gap lists as well as assess data completeness for both future ESA reprocessing campaigns and data preservation activities. The consolidation was carried out first by removing fully overlapping products, products completely covered by other products (inside) and black-listed products. Secondly, remaining products HDR and DBL files were scanned to detect filename misalignments with specifications, intra-products and inter-products gaps and corrupted products. Ancillary data from several Aeolus facilities (KSAT, DISC, FOS, PDGS) were used for gaps justification and blacklisted products identification. For FM-A VC01, 4219 products were analysed. Out of these, 3927 were classified as Master, 142 as inside, 3 as Duplicates and 147 as Blacklisted. 57 gaps were found. No data corruption was found. No duplicated source packet data was found. Consolidation results are available at ESA and includes: list of gaps with metadata and known justification,  list of duplicated events with metadata, list of Instrument Function IDs with metadata, master dataset list and a list of discarded products including known justification.

How to cite: Comparetti, N., Colamussi, G., De Laurentis, M., Douzal, M., Fischer, P., Paciucci, A., Schipperijn, B., Smeets, J., and Veneziani, M.: Consolidation of Aeolus FMA and FMB datasets in the DSI X-PReSS Consortium: Methodology used to generate Master Datasets and the results that have been achieved, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6924, https://doi.org/10.5194/egusphere-egu2020-6924, 2020.

Title: One million feet view of Level-2 Processing Facility managed at European Centre for Medium-Range Weather Forecasts (ECMWF)

Authors: Rakesh Prithiviraj, Ioannis Mallas, Cristiano Zanna 

Affiliation of authors: European Centre for Medium-Range Weather Forecasts (ECMWF)

Abstract text
Launched in August 2018, European Space Agency’s Aeolus satellite mission measures Earth's wind profile from space. The Aeolus ground segment mainly comprises of:
• Flight Operations Segment (FOS) to monitor and control Aeolus satellite and the instrument onboard, 
• Payload Data Ground Segment (PDGS) for the acquisition and systematic generation of Level-1A and Level-1B products and 
• Level-2 Processing Facility (L2PF) at ECMWF for the generation and dissemination of Level-2B and Level-2C products. 

ECMWF is both a research institute and a 24/7 operational service, producing global numerical weather predictions and other data for our Member and Co-operating States and the broader community. ECMWF relies on its atmospheric model and data assimilation system which is called the Integrated Forecasting System (IFS) to make weather predictions. ECMWF has one of the largest supercomputer facilities and meteorological data archives in the world.

This talk focusses on the Aeolus L2PF facility at ECMWF providing an overview of the processing infrastructure, relevant dataflows, monitoring system and presents the technical/system perspective of Aeolus L2PF in the context of weather forecast. The L2PF facility receives L1B data from Aeolus PDGS and systematically generates and disseminates L2B products and L2C products. The centre is also responsible for the generation of meteorological auxiliary data which is one of the critical inputs for the L2B generation.  The talk also shows various components at ECMWF that work together to achieve more than 99% L2B completeness. The components include ECMWF Production Data Store (ECPDS), ECMWF's High Performance Computing Facility (HPCF) and L2PF cluster. 

The talk concludes with references to tests carried out at ECMWF that have demonstrated that new wind profile observations from Aeolus satellite significantly improve weather forecasts, particularly in the southern hemisphere and the tropics. Because the positive impact of Aeolus on the weather predictions, Aeolus data is expected to be part of the operational weather forecast system at ECMWF in January 2020.

How to cite: Prithiviraj, R.: One million feet view of Level-2 Processing Facility managed at European Centre for Medium-Range Weather Forecasts (ECMWF), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2391, https://doi.org/10.5194/egusphere-egu2020-2391, 2020.

ESRAD and MARA, , respectivelyThe Aeolus HLOS wind component (L2B) is also compared to the corresponding component of winds derived from the HARMONIE model for the ESRAD collocations and from the ECMWF ERA5 re-analysis for the MARA collocations. We estimate bias, root-mean-squared error and correlation for the Aeolus winds the radar and model data.

How to cite: Lindskog, M., Belova, E., Voelger, P., Kirkwood, S., Körnich, H., Hagelin, S., Chatterjee, S., and Satheesan, K.: Validation of Aeolus winds using atmospheric radars in Arctic Sweden and in Antarctica and NWP modelling, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4928, https://doi.org/10.5194/egusphere-egu2020-4928, 2020.

Exceptionally strong wildfire activity in Australia in summer 2019-2020 triggered the evolution of pyrocumulonimbus clouds, releasing enormous amounts of fire smoke into the upper troposphere and lower stratosphere region of the usually very clean southern hemisphere. Measurements at the lidar site of Punta Arenas (53°S), Chile, show that the first stratospheric smoke layers arrived over Punta Arenas at 6 Jan 2020.

First results show striking similarities to a record-breaking event of stratospheric smoke layers from wildfires in Canada in 2017 (Baars et al., ACP 2019). At Punta Arenas, lidar ratios reach values of 45-50 sr at 355 nm, and 60-65 sr at 532 nm wavelength. Particle linear depolarization ratios reach values of 19% at 355 nm, and 15% at 532 nm wavelength.

Aeolus is able to detect these intense layers of stratospheric smoke in the southern hemisphere as well. In this contribution, we will discuss our findings of extensive and intensive smoke optical properties over Punta Arenas to the related Aeolus aerosol spin off products of nearby overpasses. Especially the particle linear depolarization ratio at 355 nm are of relevance as AEOLUS is only able to measure the co-polarized 355 nm signal.

How to cite: Ohneiser, K., Baars, H., Jimenez, C., Bühl, J., Seifert, P., Floutsi, A., Radenz, M., Wandinger, U., and Ansmann, A.: Stratospheric Australian fire smoke layers over Punta Arenas, Chile, measured by ground-based lidar and AEOLUS, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5140, https://doi.org/10.5194/egusphere-egu2020-5140, 2020.

Clouds and aerosols play an important role in the Earth’s energy budget through a complex interaction with solar, atmospheric, and terrestrial radiation, and air humidity. Optically thick clouds efficiently reflect the incoming solar radiation and, globally, clouds are responsible for about two thirds of the planetary albedo. Thin cirrus trap the outgoing longwave radiation and keep the planet warm. Aerosols scatter or absorb sunlight depending on their size and shape and interact with clouds in various ways.

Due to the importance of clouds and aerosols for the Earth’s energy budget, global satellite observations of their properties are essential for climate studies, for constraining climate models, and for evaluating cloud parameterizations. Active sounding from space by lidars and radars is advantageous since it provides the vertically resolved information. This has been proven by CALIOP lidar which has been observing the Earth’s atmosphere since 2006. Another instrument of this kind, CATS lidar on-board ISS provided measurements for over 33 months starting from the beginning of 2015. The ALADIN lidar on-board ADM/Aeolus has been measuring horizontal winds and aerosols/clouds since August 2018. More lidars are planned – in 2021, the ATLID/EarthCare lidar will be launched and other space-borne lidars are currently in the development phase.

Needless to say that the quality of the retrieved data strongly depends on the quality of the calibration of the lidar system and its components. Besides “classical” calibration methods (laboratory calibration, calibration in space using on-board sources and/or known external sources and  calibration through collocation, which involves comparisons with ground-based station-, balloon-, and aircraft measurements), one can also make use of a vicarious calibration, where the sites with known properties are used. In this work, we use the whole atmosphere for quality control of the space-borne lidar system, which includes the laser, the sending optics, the receiver with its telescope, and the detection system.

We describe the quality control approach based on a set of several indicators, which characterize the behavior of the lidar system on a day-to-day basis using the L1 (and even L2) data as an input. With the help of this set one can trace:

(a) the stability of the detection chain for the lidar channels (Rayleigh, Mie);

(b) the drift of crosstalk coefficients;

(c) the stability of day- and nighttime stratospheric noise;

(d) the stability of the radiation detection for all atmospheric scenarios and over the whole globe using a clustering algorithm applied to the scattering ratio (SR) histograms.

We demonstrate the results using the L1B and L2A data flow of Aeolus obtained from the first days of its operation and up to now, compare them with the results obtained for CALIOP, and discuss the applications of the approach.

How to cite: Feofilov, A., Chepfer, H., Noel, V., and Chiriaco, M.: Statistically based calibration/validation control of space-borne lidars: application to ALADIN lidar onboard ADM/Aeolus, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10697, https://doi.org/10.5194/egusphere-egu2020-10697, 2020.

ESA’s Aeolus mission, launched in August 2018, is designed to capture tropospheric wind profiles on a global scale in near-real time. The Aeolus lidar system, Atmospheric LAser Doppler INstrument (ALADIN), uses two modes of lidar-driven active scattering, Mie and Rayleigh scattering channels, to retrieve horizontal line-of-sight (HLOS) winds under both clear and cloudy conditions. ESA Aeolus aims to improve numerical weather and climate prediction, and to advance understanding of atmospheric circulation and weather systems.

This presentation will describe the Canadian validation activities for ESA Aeolus level-2B product, coordinated by the University of Toronto’s Department of Physics and Environment and Climate Change Canada (ECCC). The main focus is the evaluation of Aeolus overpasses using the fifth major global reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5), and in-situ measurements at Environment and Climate Change Canada’s (ECCC) Iqaluit and Whitehorse supersites where several wind sensing instruments are co-located. It will compare the Aeolus HLOS winds with the profiles of wind vector from regular radiosonde launches, line-of-sight winds from Doppler Lidar and Ka-Band Radar. The accuracy of the Aeolus measurements is analyzed based on the type of scattering and natural variability of the wind on different levels.

The radiosonde measures the profiles of temperature, relative humidity, pressure, and winds twice a day with a vertical resolution of 15 m up to 30 km. On the other hand, the Mie scattered 1.5 micron Doppler Lidar retrieves LOS winds at every 3 m as well as aerosol backscatter and depolarization ratio every 5 minutes up to 3 km. Lastly, for every 10 minutes, the dual-polarization Doppler Ka-Band Radar measures the LOS wind speed and direction, cloud and fog backscatter, and depolarization ratio up to a range of 25 km with a vertical resolution of 10 m.

The wind profiles were directly compared to the profiles derived from other instruments or reanalysis. The vertical structure of the Aeolus winds, for example the wind shear, will also be compared and discussed. The validation results showed that Aeolus is providing some promising initial products and that the ERA5 reanalysis is the most consistent dataset with the Aeolus wind measurements from level-2B product.

How to cite: Chou, C.-C., Kushner, P., Mariani, Z., Rodriguez, P., and Fletcher, C.: Validation for ESA’s Aeolus Mission using the in-situ instruments at Canadian Arctic and reanalysis data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13461, https://doi.org/10.5194/egusphere-egu2020-13461, 2020.

Cyprus is strategically located in the region of the Eastern Mediterranean, the Middle East and North Africa (EMMENA). As a crossroad between Europe, Asia and Africa, it is representative of meteorological conditions and coastal areas in the EMMENA region.

Incomplete coverage with ground monitoring stations is the main limitation to make fast and significant progress in understanding the complex climate-relevant atmospheric processes around the globe and thus to improve atmospheric models used for climate change projections and extreme weather predictions. Although satellites can continuously monitor the atmosphere on a regional to global scale, they must be ground-calibrated and validated in order to incorporate satellite data into atmospheric models.

Cyprus, and especially Limassol as a coastal city, can be considered an ideal natural laboratory for advanced and comprehensive field studies on climate change, aerosol-cloud-dynamics-precipitation interaction, and the weather-precipitation-dryness complex, providing additionally valuable ground truthing observations for satellite missions.

The vision of the ERATOSTHENES Research Centre (ERC) in Cyprus is to become a Centre of Excellence for Earth Surveillance and Space-Based Monitoring of the Environment, in the framework of the EU H2020 Teaming project EXCELSIOR. Within this vision, a modern observational super site in Cyprus is of fundamental importance and will be build up for long-term profiling of the atmosphere (wind, humidity, aerosol and cloud properties, precipitation fields), in one of the hot spots of climate change increasing extreme weather events.

The ERATOSTHENES station in Limassol, Cyprus with the current instrumentation (EARLINET Raman depolarization lidar) follows the CAL/VAL activities of the AEOLUS satellite launched August 2018 through the participation to the VADAM project. Selected cases that demonstrate the complex aerosol and meteorological conditions over Eastern Mediterranean will be presented as well as lidar observations during AEOLUS overpasses over Cyprus.

Acknowledgements

The authors acknowledge the EXCELSIOR H2020-WIDESPREAD-04-2017: Teaming Phase2 project under grant agreement No 857510, ACTRIS and the ESA AEOLUS CAL/VAL VADAM project (27409). CUT team acknowledge Research and Innovation Foundation for the financial support through the SIROCCO (EXCELLENCE/1216/0217) and AQ-SERVE (INTERGRATED/0916/0016) projects.

How to cite: Mamouri, R.-E., Nisantzi, A., Ansmann, A., Bühl, J., Seifert, P., Baars, H., Amiridis, V., Wandinger, U., and Hadjimitsis, D.: The ERATOSTHENES Remote Sensing Supersite: Ground-truth observations over Cyprus, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17658, https://doi.org/10.5194/egusphere-egu2020-17658, 2020.

The earth explorer mission Aeolus from the European Space Agency for the first time worldwide opens up the possibility to directly observe Earths’ wind profiles from space. Aeolus carries a Doppler wind lidar operating at 335 nm which measures the Doppler frequency shift of backscattered laser light from air molecules and particles up to 30 km accumulated in 0.25 - 2 km vertical range bins. It’s expected that such global coverage of wind profiles helps to fill a gap in the global observing system.

As part of the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations) validation and monitoring activities for Aeolus are performed to determine and understand observation systematic and random errors. Independent ground-based measurements from radiosondes and tropospheric radar wind profilers are used as reference for the evaluation of Aeolus winds. In addition monitoring results from the global model ICON from the German Weather Service (DWD) are used to examine the results and investigate bias dependencies. An accurate understanding of the systematic errors of Aeolus wind observations is necessary for data assimilation processes. First impact experiments with an established bias correction for Aeolus wind data were run at DWD showing encouraging results for forecast improvements in upper tropospheric and lower stratospheric tropics and southern hemisphere.

How to cite: Martin, A., Geiss, A., Cress, A., and Weissmann, M.: Experimental Validation and Assimilation of Aeolus Wind Observations, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18186, https://doi.org/10.5194/egusphere-egu2020-18186, 2020.

The assimilation of the Atmospheric Laser Doppler Instrument (ALADIN) wind profile data is expected to play a significant role in improving the skills of numerical weather prediction model. In this study, we analyze the Aeolus/ALADIN data over Korea region using data obtained by radiosonde, dropsonde and the ground based windprofiler. In addition, we analyze data by comparing with atmospheric movement vector (AMV) derived from the Geostationary Korea Multi Purpose Satellite -2A (GK-2A). The ALADIN wind data within the 150 km from the radiosonde/dropsonde/windprofiler station and within ±60 minutes to their observation time are collocated. The AMV data having the closest altitude to the ALADIN altitude are compared, within the 150 km from the ALADIN observation. With the limited number of collocated data obtained from August 29^th to September 1^th, 2019, the comparison results show a rather large discrepancy. In case of the radiosonde, RMSD is estimated to be 2.50 m/s and 2.67 m/s in the Rayleigh channel and the Mie channel, respectively. In case of the AMV, the error statistics varies significantly with the quality index of AMV data. When the quality index of 0.8 is applied to the AMV data, RMSD for the infrared AMV is about 3.36 m/s. In the conference, comparison results of all instruments along with the extended time period are going to be presented.

How to cite: Shin, H., Ahn, M.-H., Kim, J., and Chung, C.-Y.: Aeolus / ALADIN data analysis in Korea , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19595, https://doi.org/10.5194/egusphere-egu2020-19595, 2020.

French ground-based Rayleigh Doppler lidars deployed at Observatoire de Haute Provence (OHP) in southern France (44° N, 6° E) and Observatoire du Maido (La Reunion island, tropical Indian Ocean, 21° S, 55° E) are among the primary instruments within ESA Aeolus Cal/Val programme.  The ground-based lidars are designed to measure vertical profiles of wind velocity in the altitude range 5 - 70 km with an accuracy better than 1 m/s up to 30 km. The horizontal wind components are obtained by measuring Doppler shift between emitted and backscattered light by means of double-edge Fabry-Perot interferometer. This technique, pioneered by French Service d’Aeronomie in 1989, is implemented in Aeolus ALADIN instrument.

We present the results of validation of Aeolus L2B horizontal line-of-sight wind profiles using the French Doppler lidars and regular radiosoundings. The point-by-point validation exercise relies on the dedicated validation campaigns at OHP in January and Maido in September-October 2019 involving simultaneous lidar acquisitions and collocated radiosonde ascents coincident with the nearest Aeolus overpasses. For evaluation of the long-term variation of the bias in Aeolus wind product, we use twice-daily routine radiosoundings performed by MeteoFrance and regular wind lidar observations at both sites.

The orbital configuration of Aeolus satellite enables 2 overpasses per week above OHP within 100 km range and 2 overpasses in the vicinity of Maido observatory, of which one being within 10 km range. Evaluation of Aeolus wind profiles is done in consideration of the expected mesoscale variability of wind field inferred from numerous lidar-radiosonde intercomparisons at both stations. In addition to the quantitative validation of Aeolus wind profiles, we attempt to evaluate the capacity of Aeolus observations in resolving fluctuations of stratospheric wind field induced by atmospheric gravity waves.

How to cite: Hauchecorne, A., Khaykin, S., Wing, R., Mariscal, J.-F., Porteneuve, J., Cammas, J.-P., Marquestaut, N., Payen, G., and Duflot, V.: Validation of ESA Aeolus wind observations using French ground-based Rayleigh Doppler lidars at midlatitude and tropical sites, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19786, https://doi.org/10.5194/egusphere-egu2020-19786, 2020.

The European Space Agency (ESA) has launched the Earth Explorer Mission Aeolus on 22 August 2018. Within the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations), Cal/Val activities for Aeolus started immediately after the instrument was turned on in space. The aim is to validate the wind and aerosol products of Aeolus and to quantify the benefits of these new measurements for weather forecasting and aerosol and cloud research.
For this purpose, ground-based aerosol and wind lidar observations have been performed at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany, and at Punta Arenas (53.13 S, 70.88 W), Chile, in the frame of the DACAPO-PESO campaign (dacapo.tropos.de). Radiosondes have been launched during the Aeolus overpasses each Friday at Leipzig in addition since mid of May 2019. In Punta Arenas, we also used Doppler cloud radar observations with respect to the validation of Mie and Rayleigh winds of Aeolus.  

Aerosol-only observations with multiwavelength-Raman polarization lidar were made at the PollyNET (Baars 2016) stations in Haifa (Israel), Dushanbe (Tajikistan), Tel Aviv (Israel), and in the United Arab Emirates (UAE) - the latter two are hosted by PollyNET partner institutions (Baars, 2016). These locations are close to the desert with frequent dense, lofted aerosol layers and are thus of particular interest for Aeolus Cal/Val. Considering the long averaging length of Aeolus (87 km) and the distance to the lidars (max. 100 km), a good agreement with respect to the co-polar backscatter coefficient is found between Aeolus and the ground-based lidars at these locations.

We will present results from the above-mentioned Cal/Val activities with respect to, both, wind and aerosol products of Aeolus. It will be shown, that one of the mission goals, namely the demonstration that wind observations from space by active remote sensing are possible, have been already achieved. Furthermore, it will be demonstrated that the spaceborne HSRL (high spectral resolution lidar) technique applied for Aeolus can provide independent backscatter and extinction measurements of aerosols – a spaceborne novelty as well. Since September 2019, also an aerosol-optimized range resolution, the so-called Mediterranean range-bin setting (MARS), is operational for Aeolus in the Eastern Mediterranean. First results show a significantly improved aerosol retrieval for this adapted instrumental setting and will be presented as well.

Reference:

Baars, H., et al. (2016), An overview of the first decade of PollyNET: An emerging network of automated Raman-polarization lidars for continuous aerosol profiling, Atmos. Chem. Phys., 16(8), 5111-5137, doi:10.5194/acp-16-5111-2016.

How to cite: Baars, H., Herzog, A., Engelmann, R., Bühl, J., Radenz, M., Seifert, P., Ansmann, A., Althausen, D., Heese, B., Hofer, J., Ohneiser, K., Hanbuch, K., Basharova, E., Gülbas, T., Chudnovsky, A., Barja, B., Filioglou, M., Komppula, M., and Wandiger, U.: Validation of Aeolus aerosol and wind products with sophisticated ground-based instruments in the Northern and Southern Hemisphere , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14242, https://doi.org/10.5194/egusphere-egu2020-14242, 2020.

Aeolus is a high-spectral resolution UV lidar. It implements two detection channels, a broadband (Rayleigh channel) and a narrowband (Mie channel). Carefully calibrated, the combination offers the possibility to derive independent estimates of the backscatter and extinction coefficients of the clouds and the aerosols, thus opening the possibility to acquire an information on their nature with the extinction-to-backscatter ratio. The presentation will show how the level-2A processor of the mission works for the retrieval of optical properties of cloud and aerosol particles, what products can be obtained with what limitations. The potential of L2A processor will be illustrated by results obtained on real data acquired since AEOLUS launch.

How to cite: Dabas, A., Flament, T., Trapon, D., and Huber, D.: Aeolus aerosol and cloud product, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5362, https://doi.org/10.5194/egusphere-egu2020-5362, 2020.

The European Space Agency, ESA deployed the first Doppler wind lidar in space within its Earth Explorer Mission Aeolus in August 2018. After the initial commissioning of the satellite and the single payload ALADIN, the mission has started to demonstrate the capability of Doppler lidar to measure wind from space. In order to provide the best Aeolus wind product possible, detailed monitoring of the instrument is crucial for analysis of system health, but also for the assessment of measurement performance and data product calibration. Within the last 1.2 years the different instrument modes to assess instrument and laser health, as well as the nominal wind processing indicated longterm instrument drifts. The laser beam profile has been monitored and showed an energy redistribution within the beam. The line of sight has slowly drifted, resulting in a change of incidence angle at spectrometer level. The impact of these observed drifts on the wind product are compensated on demand by updates of dedicated ground processing calibration files. This contribution will provide an overview about the Aeolus instrument modes and the observed stability that are needed to provide the Aeolus wind product. The current Aeolus performance has been assessed by various Numerical Weather Prediction centers. The positive outcome is represented by ECMWF’s decision to start using Aeolus data operationally on 9^th January 2020.

How to cite: Kanitz, T., Witschas, B., Marksteiner, U., Flament, T., Rennie, M., Schillinger, M., Parrinello, T., Wernham, D., and Reitebuch, O.: ESA’s Wind Lidar Mission Aeolus – Instrument Performance and Stability, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7146, https://doi.org/10.5194/egusphere-egu2020-7146, 2020.

How to cite: Letertre-Danczak, J., Benedetti, A., Quesada-Ruiz, S., Dabas, A., and Flament, T.: The ESA-funded Aeolus/EarthCARE Aerosol Assimilation Study (A3S), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21436, https://doi.org/10.5194/egusphere-egu2020-21436, 2020.