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

Docter, Nicole; Preusker, R.; Filipitsch, Florian; Kritten, L.; Schmidt, Frank; Fischer, Jürgen

doi:10.5194/egusphere-2023-150

Cited by 7 publications

(10 citation statements)

References 23 publications

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“…The dominant aerosol type can be compared to the aerosol mixing ratios applied in M-AOT. The combination of ATLID observations at 355 nm with MSI retrievals for wavelengths ≥ 670 nm (Docter et al, 2023) further supports the aerosol typing.…”

Section: Introductionsupporting

confidence: 59%

“…These products belong to the EarthCARE L2b products defined in the ESA EarthCARE production model and product list (Wehr et al, 2023;Eisinger et al, 2023). Since their generation requires input from ATLID L2a products created in the ATLID Layer Products processor (A-LAY, Wandinger et al, 2023) and MSI L2a products created in the MSI Cloud Products processor and the MSI Aerosol Optical Thickness processor (M-CLD and M-AOT, Hünerbein et al, 2022;Hünerbein et al, 2023;Docter et al, 2023), they are produced after the complete ATLID L2a and MSI L2a processing is completed. An overview about the main input and output parameters and the respective products in which they are contained is provided for the cloud products in Table 1 and for the aerosol products in Table 2.…”

Section: Aerosol Typing From Combined Active and Passive Remote Sensingmentioning

confidence: 99%

“…The vertical profiles of clouds and aerosol layers along the satellite track are provided by the active instruments ATLID and CPR (e.g., van Zadelhoff et al, 2023;Donovan et al, 2023b;Kollias et al, 2022;Irbah et al, 2022). In order to get information about the scene apart from the satellite track, the passive imager MSI is necessary which provides columnar observations over a 150 km wide swath (Docter et al, 2023;Hünerbein et al, 2022;Hünerbein et al, 2023). The idea of combining the vertical information from ATLID along track ("curtain") with the columnar information from MSI along and across track ("carpet") is illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Combinations of these wavelengths are used to derive a cloud mask which is provided in the MSI Cloud Mask product (M-CM, Hünerbein et al, 2022) and to retrieve cloud optical properties such as the cloud optical thickness (COT), CTH and the effective radius of the cloud droplets which is provided in the MSI Cloud Optical and Physical product (M-COP, Hünerbein et al, 2023). Aerosol products such as the aerosol optical thickness are retrieved for the cloud-free pixels and stored in the MSI Aerosol Optical Thickness product (M-AOT, Docter et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionsupporting

confidence: 59%

Section: Aerosol Typing From Combined Active and Passive Remote Sensingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…The Multi-Spectral Imager (MSI) will provide scene context information left and right of the satellite nadir track where the active instruments, ATLID and CPR, are measuring vertical cloud/aerosol/precipitation profiles. MSI observations are used to derive "MSI-only" cloud and aerosol data products across the swath (Docter et al, 2023;Hünerbein et al, 2022a, b;Nakajima et al, 2019). The MSI nadir pixel is used in the retrieval of synergistic products with ATLID (Haarig et al, 2022) or ATLID and CPR .…”

Section: The Multi-spectral Imager -Msimentioning

confidence: 99%

The EarthCARE Mission – Science and System Overview

Wehr

Kubota

Tzeremes

et al. 2023

Preprint

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Abstract. The Earth Cloud Aerosol and Radiation Explorer (EarthCARE) is a satellite mission implemented by the European Space Agency (ESA) in cooperation with the Japan Aerospace Exploration Agency (JAXA) to measure global profiles of aerosols, clouds and precipitation properties together with radiative fluxes and derived heating rates. The data will be used in particular to evaluate the representation of clouds, aerosols, precipitation and associated radiative fluxes in weather forecasting and climate models. The satellite scientific payload consists of four instruments, a lidar, a radar, an imager and a broad-band radiometer. The measurements of these instruments are processed in the ground segment, which produces and distributes the science data products. The EarthCARE observational requirements are addressed. An overview is given of the space segment with a detailed description of the four science instruments. Furthermore, the elements of the Space Segment and Ground Segment that are relevant for the science data users are described.

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

Wandinger¹,

Floutsi²,

Baars³

et al. 2023

Atmos. Meas. Tech.

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Abstract. The Hybrid End-To-End Aerosol Classification (HETEAC) model for the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is introduced. The model serves as the common baseline for the development, evaluation, and implementation of EarthCARE algorithms. It guarantees the consistency of different aerosol products from the multi-instrument platform and facilitates the conformity of broad-band optical properties needed for EarthCARE radiative-closure assessments. While the hybrid approach ensures that the theoretical description of aerosol microphysical properties is consistent with the optical properties of the measured aerosol types, the end-to-end model permits the uniform representation of aerosol types in terms of microphysical, optical, and radiative properties. Four basic aerosol components with prescribed microphysical properties are used to compose various natural and anthropogenic aerosols of the troposphere. The components contain weakly and strongly absorbing fine-mode and spherical and non-spherical coarse-mode particles and thus are representative for pollution, smoke, sea salt, and dust, respectively. Their microphysical properties are selected such that good coverage of the observational phase space of intensive, i.e., concentration-independent, optical aerosol properties derived from EarthCARE measurements is obtained. Mixing rules to calculate optical and radiative properties of any aerosol blend composed of the four basic components are provided. Applications of HETEAC in the generation of test scenes, the development of retrieval algorithms for stand-alone and synergistic aerosol products from EarthCARE's atmospheric lidar (ATLID) and multi-spectral imager (MSI), and for radiative-closure assessments are introduced. Finally, the implications of simplifying model assumptions and possible improvements are discussed, and conclusions for future validation and development work are drawn.

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

Cited by 7 publications

References 23 publications

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

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

The EarthCARE Mission – Science and System Overview

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

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