HETEAC – The Hybrid End-To-End Aerosol Classification model for EarthCARE

Wandinger, Ulla; Floutsi, Athena Augusta; Baars, Holger; Haarig, Moritz; Ansmann, Albert; Hünerbein, Anja; Docter, Nicole; Donovan, David; Zadelhoff, Gerd-Jan van; Mason, Shannon; Cole, Jason N. S.

doi:10.5194/egusphere-2022-1241

Cited by 12 publications

(15 citation statements)

References 56 publications

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“…The aerosol optical properties needed for the radiative transfer simulations are AOT, the aerosol scattering phase function P A (Θ) and single scattering albedo ω 0 (λ) for a given aerosol type, where Θ is the scattering angle. In order to ensure consistency and comparability between EarthCARE Level-2 products, microphysical properties (size distribution and complex refractive index) of the four HETEAC (Wandinger et al, 2016(Wandinger et al, , 2022 types sea salt, non-spherical dust, fine mode weakly and strongly absorbing aerosol have been used. The optical properties, e.g.…”

Section: Forward Modelmentioning

confidence: 99%

Aerosol optical depth retrieval from the EarthCARE multi-spectral imager: the M-AOT product

Docter¹,

Preusker²,

Filipitsch

et al. 2023

Preprint

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Abstract. The Earth Explorer mission Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) will not only provide profile information on aerosols but will also deliver a horizontal context to it through measurements by its Multi-Spectral Imager (MSI). The columnar aerosol product relying on these passive signals is called M-AOT. Its main parameters are aerosol optical thickness (AOT) at 670 nm over ocean and, where possible land, and at 865 nm over ocean. Here, the algorithm and assumptions behind it are presented. Further, first examples of product parameters are given based on applying the algorithm to simulated EarthCARE test data and Moderate Resolution Imaging Spectroradiometer (MODIS) Level-1 data. Comparisons to input fields used for simulations, to the official MODIS aerosol product, AErosol RObotic NETwork (AERONET) and to Maritime Aerosol Network (MAN) show an overall reasonable agreement. Over ocean correlations are 0.98 (simulated scenes), 0.96 (compared to MYD04) and 0.9 (compared to MAN). Over land correlations are 0.62 (simulated scenes), 0.87 (compared to MYD04) and 0.77 (compared to AERONET). A concluding discussion will focus on future improvements necessary and envisioned to enhance the product.

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Section: Forward Modelmentioning

confidence: 99%

Aerosol optical depth retrieval from the EarthCARE multi-spectral imager: the M-AOT product

Docter¹,

Preusker²,

Filipitsch

et al. 2023

Preprint

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“…In case of EarthCARE, the Hybrid End-To-End Aerosol Classification model (HETEAC, Wandinger et al, 2022) is the underlying aerosol model linking the optical, microphysical and radiative properties of aerosol mixtures.…”

Section: Aerosol Typing From Combined Active and Passive Remote Sensingmentioning

confidence: 99%

Cloud top heights and aerosol columnar properties from combined EarthCARE lidar and imager observations: the AM-CTH and AM-ACD products

Haarig

Hünerbein

Wandinger

et al. 2023

Preprint

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Abstract. The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) is the combination of multiple active and passive instruments on a single platform. The Atmospheric Lidar (ATLID) provides vertical information of clouds and aerosol particles along the satellite track. In addition, the Multi-Spectral Imager (MSI) collects the multispectral information from the visible till the infrared wavelengths over a swath width of 150 km across the track. The ATLID–MSI Column Products processor (AM-COL) described in this paper combines the high vertical resolution of the lidar along track and the horizontal resolution of the imager across track to better characterize the 3-dimensional scene. ATLID Level 2a (L2a) data from the ATLID Layer Products processor (A-LAY) and MSI L2a data from the MSI Cloud Products processor (M-CLD) and the MSI Aerosol Optical Thickness processor (M-AOT) as well as MSI Level 1c (L1c) data are used as input to produce the synergistic columnar products: the ATLID–MSI Cloud Top Height (AM-CTH) and the ATLID–MSI Aerosol Column Descriptor (AM-ACD). The coupling of ATLID (measuring at 355 nm) and MSI (at ≥ 670 nm) provides multispectral observations of the aerosol properties. Especially, the Ångström exponent from the spectral aerosol optical thickness (AOT 355 nm/670 nm) adds valuable information for aerosol typing. The AOT across track, the Ångström exponent and the dominant aerosol type are stored in the AM-ACD product. The accurate detection of the Cloud Top Height (CTH) with lidar is limited to the ATLID track. The difference of the CTH detected by ATLID and MSI is calculated along track. The similarity of MSI pixels across track with those along track is used to transfer the calculated CTH difference to the entire MSI swath. In this way, the accuracy of the CTH is increased to achieve the EarthCARE mission goal aiming to derive the radiative flux at the top of the atmosphere with an accuracy of 10 Wm−2 for a 100 km2 snapshot view of the atmosphere. The synergistic CTH difference is stored in the AM-CTH product. The quality status depending on day/night conditions or the presence of multiple cloud or aerosol layers is provided with the products. The algorithm was successfully tested using the common EarthCARE test scenes. Two definitions of the CTH from the model-truth cloud extinction fields are compared: An extinction-based threshold of 20 Mm−1 provides the geometric CTH and a cloud-optical-thickness threshold of 0.25 describes the radiative CTH. The first one is detected with ATLID, the second one with MSI.

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“…In addition to ACM-CAP's synergistic retrievals, an alternate "best estimate" is produced, and can be used if ACM-CAP data are unavailable, based on compositing L2a retrievals that use ATLID (A-ICE) (Donovan et al 2022) and 130 CPR (C-CLD) (Mroz et al 2022) observations. The L2a-composite's cloud properties come from either A-ICE or C-CLD as subject to an indication of columnar cloudiness from the M-COP processor (Hünerbein et al 2022). If for a grid-cell A-ICE or C-CLD reports cloud water content greater than zero, their cloud properties, as reported, enter into the L2a-composite.…”

Section: Construction Of "L2a-composite" Cloud and Aerosol Profilesmentioning

confidence: 99%

“…Spectral aero  , aero  and aero g for the RT models are averages over wavelength intervals listed above. To generate these in a manner consistent with the 195 retrievals, optics are computed following (Wandinger et al 2022). The same radiative properties for basic aerosol types are used, which are then externally mixed to generate radiative properties for the aerosol mixtures used in AC-TC.…”

Section: Aerosolsmentioning

confidence: 99%

Broadband Radiative Quantities for the EarthCARE Mission: The ACM-COM and ACM-RT Products

Cole

Barker

et al. 2022

Preprint

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Abstract. The EarthCARE satellite mission’s objective is to retrieve profiles of aerosol and water cloud physical properties from measurements made by its cloud-profiling radar, backscattering lidar, and passive multi-spectral spectral imager (MSI). These retrievals, together with other geophysical properties, are input into broadband (BB) radiative transfer (RT) models that predict radiances, and fluxes, commensurate with measurements made, and inferred from, EarthCARE’s BB radiometer (BBR). The scientific goal is that modelled and “observed” BB fluxes differ, on average, by less than ±10 W m-2. When sound synergistic retrievals from the ACM-CAP process are available, they are acted on by the RT models. When they are not available, the RT models act on “composite” atmospheric profiles of retrievals from individual sensors. “Compositing” is performed in the ACM-COM process as described in this report. The majority of this report describes the RT models, and their products, that make-up Earth-CARE’s ACM-RT process. Shortwave (SW) and longwave (LW) flux and heating rate (HR) profiles are computed by 1D RT models for each ~1 km nadir column of inferred properties. 3D RT models compute radiances for the BBR’s three viewing directions, with the SW model also computing flux and HR profiles; the 3D LW model produces upwelling flux at just one level. All 3D RT products are averages over 5 x 21 km “assessment domains” that are constructed using MSI data. A subset of ACM-RT’s products is passed forward to the “radiative closure assess-ment” process that quantifies, for each assessment domain, the likelihood that EarthCARE’s goal has been achieved. As EarthCARE represents the first mission to make “operational” use of 3D RT models, emphasis in this report is placed on differences between 1D and 3D RT results. For upwelling SW flux at 20 km altitude, 1D and 3D values can be expected to differ by more than EarthCARE’s scientific goal of ±10 W m-2 at least 50 % of the time.

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HETEAC – The Hybrid End-To-End Aerosol Classification model for EarthCARE

Cited by 12 publications

References 56 publications

Aerosol optical depth retrieval from the EarthCARE multi-spectral imager: the M-AOT product

Aerosol optical depth retrieval from the EarthCARE multi-spectral imager: the M-AOT product

Cloud top heights and aerosol columnar properties from combined EarthCARE lidar and imager observations: the AM-CTH and AM-ACD products

Broadband Radiative Quantities for the EarthCARE Mission: The ACM-COM and ACM-RT Products

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