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/amt-16-3437-2023

Cited by 6 publications

(4 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The columnar aerosol classification probability is an important input parameter for the AM-COL algorithm (Haarig et al, 2023), which combines the ATLID aerosol typing with the MSI aerosol classification provided in the M-AOT product (Docter et al, 2023).…”

Section: Columnar Aerosol Classification Probabilitymentioning

confidence: 99%

“…The active instruments ATLID and CPR contribute with vertically resolved measurements for a two-dimensional (2D) atmospheric cross section along the satellite track (e.g., Donovan et al, 2023a;Kollias et al, 2023;Mroz et al, 2023;Irbah et al, 2023). The passive imager MSI provides observations of columnar aerosol and cloud properties across a 150 km wide swath (Docter et al, 2023;Hünerbein et al, 2023b, a), which are used to extend the 2D cross sections from lidar and radar into the 3D domain (Haarig et al, 2023;Qu et al, 2023). With this approach, 3D radiation modeling and closure assessments become possible; i.e., modeled TOA radiances and fluxes can be compared with those derived from BBR measurements (Cole et al, 2022;Barker et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

“…EarthCARE mission requirements call for the quantification of absorbing or non-absorbing aerosols from natural and anthropogenic sources. Information on the spectral AOT is of interest in this context (see, e.g., Wandinger et al, 2023) and can be gained by combining ATLID measurements at 355 nm with MSI observations at 670 nm (over land and ocean) and 865 nm (over ocean) available from the MSI AOT product (M-AOT; Docter et al, 2023). Respective Ångström exponents, together with track-to-swath extrapolations, are provided in the AM-ACD product (Haarig et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cloud top heights and aerosol layer properties from EarthCARE lidar observations: the A-CTH and A-ALD products

Wandinger,

Haarig,

Baars

et al. 2023

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. The high-spectral-resolution Atmospheric Lidar (ATLID) on the Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) provides vertically resolved information on aerosols and clouds with unprecedented accuracy. Together with the Cloud Profiling Radar (CPR), the Multi-Spectral Imager (MSI), and the Broad-Band Radiometer (BBR) on the same platform, it allows for a new synergistic view on atmospheric processes related to the interaction of aerosols, clouds, precipitation, and radiation at the global scale. This paper describes the algorithms for the determination of cloud top height and aerosol layer information from ATLID Level 1b (L1b) and Level 2a (L2a) input data. The ATLID L2a Cloud Top Height (A-CTH) and Aerosol Layer Descriptor (A-ALD) products are developed to ensure the provision of atmospheric layer products in continuation of the heritage from the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Moreover, the products serve as input for synergistic algorithms that make use of data from ATLID and MSI. Therefore, the products are provided on the EarthCARE joint standard grid (JSG). A wavelet covariance transform (WCT) method with flexible thresholds is applied to determine layer boundaries from the ATLID Mie co-polar signal. Strong features detected with a horizontal resolution of 1 JSG pixel (approximately 1 km) or 11 JSG pixels are classified as thick or thin clouds, respectively. The top height of the uppermost cloud layer together with information on cloud layering are stored in the A-CTH product for further use in the generation of the ATLID-MSI Cloud Top Height (AM-CTH) synergy product. Aerosol layers are detected as weaker features at a resolution of 11 JSG pixels. Layer-mean optical properties are calculated from the ATLID L2a Extinction, Backscatter and Depolarization (A-EBD) product and stored in the A-ALD product, which also contains the aerosol optical thickness (AOT) of each layer, the stratospheric AOT, and the AOT of the entire atmospheric column. The latter parameter is used to produce the synergistic ATLID-MSI Aerosol Column Descriptor (AM-ACD) later in the processing chain. Several quality criteria are applied in the generation of A-CTH and A-ALD, and respective information is stored in the products. The functionality and performance of the algorithms are demonstrated by applying them to common EarthCARE test scenes. Conclusions are drawn for the application to real-world data and the validation of the products after the launch of EarthCARE.

show abstract

Section: Columnar Aerosol Classification Probabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cloud top heights and aerosol layer properties from EarthCARE lidar observations: the A-CTH and A-ALD products

Wandinger,

Haarig,

Baars

et al. 2023

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

“…The passive instrument, the multi-spectral imager (MSI), gives horizontal context to the observed scene (Wandinger et al, 2023;Docter et al, 2023;Hünerbein et al, 2023b, a;Haarig et al, 2023) and is used to create 3D scenes (Qu et al, 2023). The 3D information of the atmosphere based on measurements of these instruments (Mason et al, 2023) will be used as input for 1D and 3D-radiative transfer calculations (Cole et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Retrieval of top-of-atmosphere fluxes from combined EarthCARE LiDAR, imager and broadband radiometer observations: the BMA-FLX product

Velázquez Blázquez,

Domenech,

Baudrez

et al. 2024

Preprint

View full text Add to dashboard Cite

Abstract. The Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) satellite mission is expected to provide new insights into aerosols, clouds, and radiation. The satellite’s payload include four instruments design to synergistically retrieve vertical profiles of clouds and aerosols, along with the atmospheric radiation data. This will enable the determination of atmospheric heating rates and top-of-atmosphere radiances and fluxes. This paper focuses on the BMA-FLX processor, an algorithm specifically created, developed, and validated to retrieve thermal and solar top-of-atmosphere radiative fluxes from longwave and shortwave radiances, measured along-track by the EarthCARE Broadband Radiometer (BBR) instrument. These measurements are co-registered either at the surface or at the radiatively most significant vertical layer of the atmosphere in cloudy condition (reference level). The Multi-Spectral Imager (MSI) and Atmospheric LiDAR (ATLID) on-board EarthCARE support cloud identification, while meteorological data from the European Centre for Medium-Range Weather Forecasts provide the surface and atmospheric necessary information. In the BMA-FLX processor, flux is estimated independently for each BBR view using different approaches for the longwave and shortwave radiances. A combined flux, derived from co-registered radiances at the reference level, is provided as the best estimate for a given scene. The radiance-to-flux conversion algorithms have been successfully validated through end-to-end verification using L1 and L2 synthetic data for three EarthCARE orbits. The BMA-FLX’s objective is to achieve radiative closure for EarthCARE with solar and thermal fluxes within 10 Wm−2.

show abstract

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

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. The Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) is a 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 multi-spectral information from the visible to 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 a three-dimensional scene. ATLID Level 2a (L2a) data from the ATLID Layer Products processor (A-LAY), MSI L2a data from the MSI Cloud Products processor (M-CLD) and the MSI Aerosol Optical Thickness processor (M-AOT), and 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 multi-spectral observations of the aerosol properties. In particular, the Ångström exponent from the spectral aerosol optical thickness (AOT 355/670 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 in the CTH detected by ATLID and retrieved by 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's goal of deriving the radiative flux at the top of the atmosphere with an accuracy of 10 W m−2 for a 100 km2 snapshot view of the atmosphere. The synergistic CTH difference is stored in the AM-CTH product. The quality status is provided with the products. It depends, e.g., on day/night conditions and the presence of multiple cloud layers. 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 CTH definition was detected with ATLID and the second one with MSI. The geometric CTH is always higher than or equal to the radiative CTH.

show abstract

Aerosol optical depth retrieval from the EarthCARE Multi-Spectral Imager: the M-AOT product

Cited by 6 publications

References 70 publications

Cloud top heights and aerosol layer properties from EarthCARE lidar observations: the A-CTH and A-ALD products

Cloud top heights and aerosol layer properties from EarthCARE lidar observations: the A-CTH and A-ALD products

Retrieval of top-of-atmosphere fluxes from combined EarthCARE LiDAR, imager and broadband radiometer observations: the BMA-FLX product

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

Contact Info

Product

Resources

About