Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission (Illingworth et al. 2015) is designed to produce the maximum synergetic collaboration of European and Japanese science teams (Wehr et al. 2023, Eisinger et al. 2024). The EarthCARE products will be developed and distributed from both JAXA and ESA. Continuous exchanges of information have been conducted between Japan and Europe through the Joint Algorithm Development Endeavor (JADE). CPR, ATLID and MSI Level-2 provide cloud mask, cloud phase and cloud microphysics (such as cloud effective radius, liquid water content, optical depth, etc) for the respective sensor products, together with the synergy products by using the combination of the sensors. Further, the CPR provides the Doppler velocity measurement (which gives the vertical information of the in-cloud velocity), and precipitation products. ATLID Level-2 includes aerosol flagging, aerosol component type (such as dust, black carbon, sea salt and water soluble), as well as the aerosol optical properties including aerosol extinction. The cloud and aerosol products will be used to derive the radiative flux at shortwave and longwave, whose consistency with the BBR will be checked to produce the final radiation product by 4-sensors.

EarthCARE synthetic data using a global storm-resolving (NICAM) and Joint-Simulator (Joint Simulator for Satellite Sensors) have been developed in Japan and used in the JAXA L2 algorithm developments (Roh et al. 2023).

Validation activities are necessary to distribute the scientific products whose quality and reliability are assured. The JAXA is planning the validation activities by utilization of the existing observation network, campaign observation, and cross comparison with other satellite data.

Furthermore, a wide range of application research activities will be planned to achieve the mission objectives. EarthCARE observation data will contribute to understanding cloud, aerosol, and radiation processes, evaluations and improvements of climate models and numerical weather prediction (NWP) models, and atmospheric quality monitoring. JAXA is conducting joint-works with universities and research institutes. The Intergovernmental Panel on Climate Change (IPCC) report published in August 2021, “Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the IPCC”, summarizes that the cloud feedback remains the largest contribution to overall uncertainty, and contributions to mitigate the uncertainty can be expected by new insights by the EarthCARE observations.

This presentation will introduce JAXA Level 2, Validation and Applications Preparation for the EarthCARE mission.

How to cite: Kubota, T. and Okamoto, H.: JAXA Level-2 Algorithms, Validations and Applications Preparation for the EarthCARE, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4236, https://doi.org/10.5194/egusphere-egu24-4236, 2024.

ATLID (Atmospheric Lidar) is the lidar to be embarked on the Earth Clouds and Radiation Explorer (EarthCARE) mission. EarthCARE is a joint ESA-JAXA mission and will embark a cloud/aerosol lidar (ATLID), a cloud-profiling Radar (CPR) a multispectral cloud/aerosol imager (MSI) and a three—view broad-band radiometer (BBR). ATLID is a 355nm high-spectral-resolution, polarization sensitive lidar.

The accurate retrieval of aerosol and cloud properties from space-based lidar is a challenging endeavor, even when the extra information provided by an HSRL system is exploited. The generally low signal-to-noise (SNR) ratios involved coupled with the need to respect the structure of the aerosol and cloud fields being sensed are particular challenges.

Over the past several years, 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. Two of these ATLID processors are A-FM (ATLID featuremask) and A-PRO (ATLID profile processor). A-FM uses techniques adapated from the field of image processing to detect the presence of targets at high resolution while A-PRO (using A-FM as input) preforms a multi-scale optimal-estimation technique in order to retrieve both aerosol and cloud extinction and backscatter profiles.

Adaptations of the A-FM and A-PRO processors have been developed for Aeolus (called AEL-FM and AEL-PRO, respectively) and have been introduced into the Aeolus L2a operational processor. In this presentation A-FM and A-PRO will be described. Results based on simulated data for A-FM and A-PRO and results using AEL-FM and AEL-PRO using Aeolus observations will be presented and discussed.

How to cite: Donovan, D., van Zadelhoff, G.-J., and Wang, P.: The EarthCARE ATLID profile processors, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16225, https://doi.org/10.5194/egusphere-egu24-16225, 2024.

This presentation delves into the C-CLD processor and its output product, both named the same, developed for the EarthCARE mission. The C-CLD processor has been designed to extract detailed microphysical properties of clouds and precipitation from the EarthCARE Cloud Profiling Radar data. The algorithm introduces a significant advancement by incorporating Doppler velocity information for the first time in space-borne radar retrievals. Our approach integrates an optimal estimation method to deduce vertical profiles of hydrometeor water content and particle characteristic size, employing reflectivity, mean Doppler velocity measurements, and path-integrated attenuation. The algorithm's robustness is further amplified by an ensemble-based method in the ice regions, ensuring both accuracy and consistency in the forward model relations.

Emphasizing the algorithm's advancements, we present a comprehensive overview of its theoretical basis and development. This includes the validation process, performance sensitivity analysis and quantification of the information content. The presentation will demonstrate the retrieval efficacy in diverse atmospheric conditions, ranging from warm to cold rain and snow.

In addition to algorithmic developments, our research also emphasizes the importance of iterative testing and refinement. Our approach combines model simulations with actual campaign datasets, which include both in-situ and remote sensing measurements, to validate and refine our methods. The rigorous analysis of data from campaigns like CADDIWA or IMPACTS, provided insights that allowed us to improve the C-CLD algorithm, ensuring its robustness and improving the reliability of its retrievals.

How to cite: Mroz, K., Puidgomènech Treserras, B., Battaglia, A., and Kollias, P.: Cloud and Precipitation Microphysical Retrievals from the EarthCARE Cloud Profiling Radar: The C-CLD Product, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17575, https://doi.org/10.5194/egusphere-egu24-17575, 2024.

JAXA L2-algorithms for cloud properties and vertical velocity were developed for the EarthCARE mission. CPR will be the first 94GHz Doppler cloud radar in space and ATLID is the 355nm-high spectral resolution lidar that can provide backscattering, extinction and depolarization ratio. The JAXA L2 standard cloud products will be derived by using (1) CPR-only algorithms without Doppler velocity, (2) CPR and ATLID algorithms and (3) CPR. ATLID and MSI algorithms. The JAXA L2 research product will be produced by using Doppler velocity (Vd) from CPR in addition to above. The products include cloud mask, cloud particle type, cloud particle categories, terminal velocity and vertical air motion. The L2 algorithms correspond to the extended version to those for CloudSat, CALIPSO (Hagihara et al., 2010 for cloud mask, Yoshida et al., 2010 and Kikuchi et al., 2017 for cloud particle type and Okamoto et al., 2010, Sato and Okamoto 2011 for cloud microphysics) and the latter has been distributed as JAXA EarthCARE A-train products. Vd may be affected by aliasing and the correction algorithm was developed. After the correction, Vd is effective to discriminate clouds and precipitation in cloud particle type products. It is also effective to specify the upward motion in convections. Cloud particle type algorithms for CPR use Vd and Ze for the better discrimination of clouds and precipitation. Two-dimensional diagram of lidar ratio and depolarization ratio from ATLID enables to retrieve ice particle categories (Okamoto et al., 2019, 2020, Sato and Okamoto 2023). The knowledge of particle categories reduce the uncertainties in the retrieved microphysics. Recently developed physical model (Sato et al., 2018) and vectorized physical model (Sato et al., 2019) were implemented into the algorithms to account multiple scattering contribution to the signals.

Synergetic ground-based observation system has been constructed in NICT Koganei, Tokyo. The ground-based system consists of 94GHz high-sensitivity-cloud radar (HG-SPIDER) and electric scanning cloud radar (ES-SPIDER), Multi-Field-of-view Multiple Scattering Polarization Lidar (Okamoto et al., 2016, Nishizawa et al., 2021), high spectral resolution lidar (Jin et al., 2020), direct-detection Doppler lidar (Ishii et al., 2022), coherent Doppler lidar (Iwai et al., 2013) and wind profiler. Cloud mask, particle type, cloud particle category, cloud microphysics, terminal velocity and vertical motion are retrieved by the system and can be used to evaluate L2 products.

How to cite: Okamoto, H., Sato, K., Nishizawa, T., and Horie, H.: Development of JAXA L2 algorithms to retrieve cloud properties and vertical velocity for the EarthCARE mission, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20244, https://doi.org/10.5194/egusphere-egu24-20244, 2024.

Improved representation of ice-phase processes in numerical models necessitates an enhanced understanding of ice-particle microphysics/radiative properties and their respective formation conditions. The EarthCARE JAXA L2 standard/research algorithms for clouds, precipitation and vertical motions aims at providing more detailed information of cloud particle categories and associated cloud microphysics/radiative properties from ATLID-CPR-MSI synergy. In particular, measurements from CPR Doppler and ATLID are expected to enable more comprehensive exploration of the relation between different cloud particle categories and the dynamical conditions. Based on complimentary information from long-term A-train data, the cloud particle category classification methodology planned for EarthCARE is tested and a new dataset has been developed. With this dataset, the geographical dependence of the occurrence of different ice cloud particle habit category and their properties that will be further investigated in detail from EarthCARE observations are discussed. Activities related to JAXA L2 validations from EU-Japan collaboration are developing new ways of combining ground-based active sensors and detailed surface observation of snow and rain to improve the quantification of precipitation and particle type retrievals. These studies would be valuable for further assessing the physical processes associated with cloud-precipitation formation from the EarthCARE mission.

How to cite: Sato, K. and Okamoto, H.: EarthCARE mission for global height-resolved cloud particle categories and vertical motion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20108, https://doi.org/10.5194/egusphere-egu24-20108, 2024.

The Broad-Band Radiometer (BBR) instrument on the EarthCARE satellite will provide accurate outgoing solar and thermal radiances at the Top of the Atmosphere (TOA) obtained in an along track configuration at three fixed viewing directions (nadir, fore and aft).

The operational BMA-FLX product on top-of-atmosphere radiative fluxes, is based on a radiance-to-flux conversion algorithm mainly fed by the unfiltered broad-band radiances, obtained in the BM-RAD product, auxiliary data from EarthCARE L2 cloud products and modelled geophysical databases. The conversion algorithm models the angular distribution of the reflected solar radiation and thermal radiation emitted by the Earth-Atmosphere system, and returns geometry independent flux estimates to be used for the radiative closure assessment of the Mission.

Different methodologies are employed for the solar and thermal BBR ADMs. Models for SW radiances are created for different scene types and constructed from Clouds and the Earth’s Radiant Energy System (CERES) data using a feed-forward back-propagation artificial neural network (ANN) technique. The LW angular models are derived through multiple regressions on brightness temperatures and brightness temperature differences of the multispectral imager (MSI) 10.8 µm and 12 µm channels, and corresponding LW fluxes obtained by using a large database of LibRadtran and SBDART radiative transfer simulations.

Both retrieval algorithms exploit the multi-viewing capability of the BBR by applying the radiance to flux conversion algorithms to each of the BBR views, which have been previously collocated at a reference level in order to minimize parallax effects. The reference height where the three BBR measurements are co-registered corresponds to the height where most reflection or emission takes place and depends on the spectral regime. LW observations are co-registered at the cloud top height while SW reference height is instead selected by minimizing the flux differences between nadir, fore and aft fluxes. The derived fluxes from the collocated views are then combined into a single flux value at the selected reference level.

Verification of the algorithms has been carried out using the 3 test scenes developed by the EarthCARE team using the Environment Canada and Climate Change’s Global Environmental Multiscale model (GEM). The BBR solar and thermal flux retrieval algorithms have been successfully employed to retrieve radiative fluxes over the 3 test scenes. Comparisons with the true fluxes from the GEM model provide RMSE < 5 W/m² for the LW fluxes and < 15 W/m² for the SW fluxes.

How to cite: Velazquez Blazquez, A., Domenech, C., Baudrez, E., Clerbaux, N., and Salas Molar, C.: Radiative fluxes estimation for the Broadband Radiometer (BBR) on EarthCARE: The BMA-FLX product, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20094, https://doi.org/10.5194/egusphere-egu24-20094, 2024.

Variational retrievals, data assimilation, and model evaluation in observation space, all rely on accurate instrument simulators, or forward models. The scientific challenge is to find innovative approximations to the radiative transfer that make them fast enough to use iteratively, while retaining accuracy. In this presentation I will summarize how the development of various forward models, particularly in the context of synergistic retrievals from EarthCARE and the A-Train, has the capability to reveal important cloud and precipitation properties that would otherwise remain hidden, and potentially even to develop new satellite concepts. For example, our radar and lidar “Multiscatter” model enables the extinction profile to be retrieved in ice and liquid clouds even in the presence of lidar multiple scattering.  Our “FLOTSAM” solar radiance model can work with profiles containing arbitrary combinations of particles, and surprisingly can help improve rain-rate retrievals by better providing the additional information needed to partition the radar path-integrated attenuation into the contributions from liquid clouds and rain. The Two-Stream Source Function (TSSF) infrared and microwave radiance model enables us to interpret 94-GHz brightness temperature, which provides important additional information on precipitating ice and liquid clouds.  I will end by presenting a new radiance model for cloud/storm-resolving models that can efficiently represent horizontal radiation transport between columns; this could enable future retrievals and assimilation to take full account of 3D radiative effects.

How to cite: Hogan, R., Mason, S., Jakub, F., and Fielding, M.: Harnessing the power of forward models: past, present and future, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8361, https://doi.org/10.5194/egusphere-egu24-8361, 2024.

How to cite: von Bismarck, J., Koopman, R., Rusli, S., Davidson, M., Bernaerts, D., Wallace, K., Fehr, T., Hummel, T., Tzallas, V., Frommknecht, B., and Eisinger, M.: EarthCARE Cal/Val Campaigns - Overview, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17361, https://doi.org/10.5194/egusphere-egu24-17361, 2024.

The WegenerNet 3D Open-Air Laboratory for Climate Change Research, located in southeastern Austria in an area of about 22 km x 16 km around the city of Feldbach (46.93°N, 15.90°E), provides a unique setup for atmospheric monitoring and validation of satellite data products. Its 3D instrumentation consists of a polarimetric X-band Doppler weather radar, a microwave radiometer for vertical profiling of temperature, humidity, and cloud liquid water, an infrared cloud structure radiometer, and a water-vapor-mapping GNSS station network. These 3D sensors complement the high-density WegenerNet hydrometeorological ground station network, which is comprised of 156 stations measuring precipitation, temperature, humidity, and (at selected locations) wind as well as soil parameters.

This highly synergistic measurement setup enables robust internal cross-evaluation, calibration and quality control for obtaining reliable observations and derived WegenerNet data products. The 3D instrumentation is operational since mid-2021 and will provide a consistent validation reference data record throughout the EarthCARE mission lifetime. With its ground-based observations of cloud base height, melting layer base and top heights, liquid water content, precipitation rates, and hydrometeor classification, the WegenerNet contributes specifically to the validation of EarthCARE L2a and L2b cloud and precipitation data products. This presentation summarizes the validation preparation activities carried out so far, with focus on the EarthCARE validation rehearsal, and gives an outlook on the planned post-launch validation work during the actual cal/val phase.

How to cite: Fuchsberger, J., Kvas, A., Kirchengast, G., Foelsche, U., Ghaemi, E., Galovic, R., Scheidl, D., and Bichler, C.: Validation of EarthCARE Cloud and Precipitation Products through the WegenerNet 3D Open-Air Laboratory facilities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8203, https://doi.org/10.5194/egusphere-egu24-8203, 2024.

The joint ESA and JAXA Earth Explorer mission EarthCARE is designed to close gabs in the knowledge of aerosol, clouds and their interactions, and effects on radiation. For this the platform comprises four remote sensing instruments observing the vertical structure of the atmosphere with a highly spectral resolving lidar and a doppler cloud radar. Together with a hyperspectral imager radiation fluxes can be inferred and compared to the measurements of the on-board broad band radiometer. Based on these four instruments EarthCARE will provide over 40 data products, which are partly synergistic products of observations of all instruments. For the success of the mission it is therefore crucial to exactly validate the individual data products and to quantify their errors. A variety of observational sources are used, reaching from ground-based stations and networks to airborne measurements, and from satellite observations to modelled data. Already in the past a number of dedicated validation campaigns to prepare for validation from German research institutes were carried out with eg. the ground-based cloud observation system LACROS or with an EarthCARE-like payload on board the German research aircraft HALO. After launch a continuous validation of EarthCARE products will be necessary. For this the German Initiative for the Validation of EarthCARE (GIVE) bundles the expertise of the German atmospheric research community and aims at the validation of the entire chain of EarthCARE Level 1 and 2 products and the evaluation of related algorithms and instrument calibrations. The GIVE project will include dedicated campaigns as well as long‐term support over the lifetime of the mission. Here we want to introduce in general the German project EC-KLIM (former project office) to prepare for the use of EarthCARE, and especially of the GIVE project. We will present an overview of past preparation campaigns and of planned German validation activities.

How to cite: Zechlau, S., Groß, S., Wandinger, U., and Baars, H.: EC-KLIM – Coordination of German EarthCARE Validation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14900, https://doi.org/10.5194/egusphere-egu24-14900, 2024.

The EUMETSAT central facility generates and disseminates several cloud products from both geostationary and low-Earth orbit passive sensors, which serve a variety of applications, spanning from nowcasting, to numerical weather prediction to climate monitoring. The retrieved cloud parameters include cloud/dust/ash detection, cloud top height and microphysics (particle effective radius and optical thickness). All EUMETSAT products are validated and continuously quality monitored against independent reference data to ensure state-of-the-art algorithm performance, product quality/accuracy compliant with user and operational service requirements, and stability and continuity/consistency over time (i.e., coping with instrument degradation, algorithm evolutions, updated calibration, etc.).

This contribution provides an overview of the tools developed at EUMETSAT to perform the monitoring and validation of cloud products against lidar/radar measurements, which have established themselves as a trustworthy source for the detection of cloud layers and superior to any other validation data source when it comes to estimate the cloud height, particle microphysical and optical properties. We focus on the status of these tools and the plans for their further development and release to users. The tools are fully automated and handle the validation of products from both geostationary and polar-orbiting satellites, including data download and organisation, instrument co-location and the development of comparison metrics. The toolkit includes:

• A tool performing the validation of EUMETSAT against space-based radar and lidar measurements. For almost two decades (since 2006), the CloudSat and CALIPSO observations have been the prime reference source for this validation. EarthCARE will provide the natural continuation to the observations provided by these two instruments, which reached their end of life in autumn 2023. We discuss the use of EarthCARE products as envisaged in the validation activities with a particular focus on the retrieval of cloud properties based on the synergistic use of lidar, radar and multi-spectral imager data. Furthermore, the higher sensitivity measurements expected from HSRL and CPR on board EarthCARE with respect to CALIPSO and CloudSat will require careful investigations in order to transfer the current experience in the use of A-Train products as a validation reference to the new EarthCARE products.
• A tool performing the validation of EUMETSAT cloud products against ground-based radar and lidar measurements from ACTRIS (the European Research Infrastructure for the observation of Aerosol, Cloud and Trace Gases), specifically using the cloud products generated by the ACTRIS-Cloudnet processing facility maintained by the Finnish Meteorological Institute (FMI). This validation activity fills in the gap between CloudSat/CALIPSO end of life and EarthCARE launch.
• METIS-Clouds (Monitoring and Evaluation of Thematic Information from Space), a web application tool providing access to the collection of monitoring and validation results of EUMETSAT cloud products, on a global and regional level. This collection is exploited by both the in-house algorithm developers (to identify and fix issues, bugs, etc.) and the users (to assess the product accuracy).

How to cite: Spezzi, L., Bozzo, A., Watts, P., Jackson, J., and Belo do Couto, A.: Use of EarthCARE products within the EUMETSAT validation facility for Level 2 Cloud products  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18904, https://doi.org/10.5194/egusphere-egu24-18904, 2024.

The JATAC campaign in September 2021 and September 2022 on and above Cape Verde Islands resulted in a large in-situ and remote measurement dataset. Its main objective was the calibration and validation of the ESA satellite Aeolus ALADIN Lidar. The campaign also featured secondary scientific objectives related to climate change. Constraining remote sensing measurements with those provided by in-situ instrumentation is crucial for proper characterization and accurate description of the 3-D structure of the atmosphere.

We present the results performed with an instrumented light aircraft (Advantic WT-10) set-up for in-situ aerosol measurements. Twenty-seven flights were conducted over the Atlantic Ocean at altitudes around and above 3000 m above sea level during intense dust transport events. Simultaneous measurements with PollyXT, and eVe ground-based lidars took place, determining the vertical profiles of aerosol optical properties, which were also used to plan the flights.

The aerosol light extinction coefficient was obtained at three different wavelengths as a combination of the absorption coefficients determined using Continuous Light Absorption Photometers (CLAP) and the scattering coefficients measured with an Ecotech Aurora 4000 nephelometer, which also measured the backscatter fraction. The particle size distributions above 0.3 µm diameter were measured with two Grimm 11-D Optical Particle Size Spectrometers (OPSS). Moreover, CO2 concentration, temperature, aircraft GPS position and altitude, air and ground speed were also measured.

We compare the in-situ aircraft measurements of the aerosol extinction coefficients with the AEOLUS lidar derived extinction coefficients, as well as with the ground-based eVe and PollyXT lidar extinction coefficients when measurements overlapped in space and time. The comparison was performed at the closest available wavelengths, with in-situ measurements inter/extrapolated to those of the lidar systems.

In general we find an underestimation of the extinction coefficient obtained by lidars compared to the in-situ extinction coefficient. The slopes of regression lines of ground-based lidars, PollyXT and eVe, against the in-situ measurements are characterised by values ranging from 0.61 to 0.7 and R² between 0.71 and 0.89. Comparison further suggests better agreement between Aeolus ALADIN lidar and the in-situ measurements. Relationship described by fitting the Aeolus to in-situ data is characterised by the slope value 0.76 and R² of 0.8.

The causes of better agreement of the in-situ measurements with the ALADIN lidar than with the surface based ones are being studied, with several reasons being considered: a) lower spatial and temporal resolution which homogenize the area of study in comparison with the very fine vertical variations of the aerosols, which can be detected with the surface-based measurements, impairing the comparison with highly vertically resolved ground-lidar measurements while not affecting averaged space-borne lidar; b) the effect of lower clouds/ Saharan air layers on the attenuation of the lidar signal.

The presented results show the importance of the comparison of the remote with in-situ measurements for the support of the research on evolution, dynamics, and predictability of tropical weather systems and provide input into and verification of the climate models.

How to cite: Bervida Mačak, M., Yus-Díez, J., Drinovec, L., Jagodič, U., Žibert, B., Lenarčič, M., Marinou, E., Paschou, P., Siomos, N., Baars, H., Engelmann, R., Skupin, A., Floutsi, A. A., Zenk, C., Fehr, T., and Močnik, G.: Aerosol Light Extinction Coefficient Closure - Comparison of Airborne In-situ Measurements with LIDAR measurements during JATAC/CAVA-AW 2021/2022 campaigns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18425, https://doi.org/10.5194/egusphere-egu24-18425, 2024.

We previously discovered the sensitivity of Aeolus lidar surface returns (LSR) to surface characteristics and reported very good agreement of LSR with Lambertian Equivalent Reflectances from passive remote sensing instruments for the first year of Aeolus on orbit. In this way, we provided the first evidence that active remote sensing can be used for retrieving unidirectional UV surface reflectivity. Here, as a continuation of this effort, we report the detailed methodological solutions for retrieving and evaluating LSR to be implemented as official L2A product during Phase-F of Aeolus project for its entire lifetime. Unlike our previous report that relied on detecting surface bin using our own methodology and assumptions, we now align the approach of detecting surface bins with the official Aeolus processing methodology for retrieving LSR and elaborate on the resultant differences. Besides that, we report how this successful application of atmospheric spaceborne lidar data for inferring land surface reflectivity properties can be translated for future lidar missions such as EarthCARE and Aeolus-2. On one hand, our results will briefly introduce all the details of the LSR retrieval for Aeolus with its unique and complex optical setup (highly-non nadir incidence and UV wavelength) for broad audience for the first time. On the other hand, we will shed light on the opportunities and challenges of LSR-alike retrievals for future lidar spaceborne missions, thereby trying to minimize the key methodological uncertainties associated with implementation of LSR algorithms.

How to cite: Labzovskii, L. D., van Zadelhoff, G.-J., Donovan, D. P., de Kloe, J., Tilstra, L. G., Stoffelen, A., Stammes, P., and Josset, D.: Presenting lidar surface returns as Aeolus product with the outlook on future spaceborne lidar missions including EarthCARE and Aeolus-2 , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12553, https://doi.org/10.5194/egusphere-egu24-12553, 2024.

EarthCARE, ESA’s and JAXA’s joint mission, is expected to launch in 2024 carrying ATLID, a high-spectral resolution lidar with depolarization capability. The instrument will provide valuable data for characterizing atmospheric aerosols and for improving atmospheric composition modelling. The aim of this study is to show how working with ESA’s Aeolus wind mission prepares us for taking advantage of ATLID.

Aeolus, which launched in 2018 and deorbited in 2023, was not specifically designed to observe aerosols but still provided aerosol products. Due to the lack of a cross-polar channel, it underestimated the aerosol-related backscatter by as much as 50% in scenes with non-spherical particles. During the ESA L2A+ project, an enhanced aerosol product was developed through data fusion with other data sources (such as NASA’s CALIPSO mission) to account for Aeolus deficiencies. The impact of this new product was assessed through assimilation experiments in regional NWP models, showing both the direct improvements of the new product, as well as the betterment of aerosol fields in regional models through assimilation of a profiling instrument. Our results were validated using data from the ESA-ASKOS tropical campaign, which took place in Cabo Verde during Summer and Autumn of 2021 and 2022.

The open-source tools created for Aeolus are further developed to support EarthCARE. Working with simulated data, we show the impact of ATLID profile assimilation on both the representation of aerosols in the model, as well as the impact on numerical weather prediction through radiative feedback. The experiments are done using the Weather Research and Forecasting (WRF) model, alongside the Data Assimilation Research Testbed (DART), with AEOLUS and EarthCARE support added.

The L2A+ team acknowledges support by ESA in the framework of the "Enhancing Aeolus L2A for depolarizing targets and impact on aerosol research and NWP project (4000139424/22/I-NS). This work was supported by computational time granted from the National Infrastructures for Research and Technology S.A. (GRNET S.A.) in the National HPC facility - ARIS - under project ID pr014048_thin.

How to cite: Georgiou, T., Tsikerdekis, A., Rizos, K., Proestakis, E., Gkikas, A., Drakaki, E., Kampouri, A., Baars, H., Floutsi, A. A., Marinou, E., Benedetti, A., McLean, W., Retscher, C., Melas, D., and Amiridis, V.: Using AEOLUS Aerosol Assimilation to pave the way for EarthCARE, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10363, https://doi.org/10.5194/egusphere-egu24-10363, 2024.