25 Nov 2022
 | 25 Nov 2022

Cloud mask algorithm from the EarthCARE multi-spectral imager: the M-CM products

Anja Hünerbein, Sebastian Bley, Stefan Horn, Hartwig Deneke, and Andi Walther

Abstract. The EarthCARE satellite mission will provide new insights into aerosol-cloud and radiation interactions by means of synergistic observations of the Earth's atmosphere from a collection of active and passive remote sensing instruments, flying on a single satellite platform. The Multi-Spectral Imager (MSI) will provide visible and infrared images in the cross-track direction with a 150 km swath and a pixel sampling at 500 m. The suite of MSI cloud algorithms will deliver cloud macro- and micro-physical properties complementary to the vertical profiles measured from the ATmospheric LIDar (ATLID) and the Cloud Profiling Radar (CPR) instruments. The MSI cloud mask algorithm (M-CM) provides a cloud flag, cloud phase and cloud type product which are essential parameters for the cloud optical and physical properties (M-COP) as well as for the aerosol optical properties (M-AOT). Synthetic test scenes from the EarthCARE end-to-end simulator provide a first overview of the expected performance of the M-CM products before launch. Validation of the MSI cloud mask algorithm against satellite products from MSG SEVIRI and MODIS demonstrates a good performance of the algorithm. The MSI cloud detection performance is not completely aligned with that from MODIS, which is however not surprising when considering the rather limited number of spectral channels of MSI in comparison to MODIS. The direct comparison to MODIS shows that some threshold tuning should be done especially over desert or sun glint regions once real observations are available. However the MSI bands are less affected by sun glint because of the asymmetric view of the imager.

Anja Hünerbein et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1240', Anonymous Referee #1, 11 Jan 2023
  • RC2: 'Comment on egusphere-2022-1240', Anonymous Referee #2, 31 Jan 2023

Anja Hünerbein et al.

Anja Hünerbein et al.


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Short summary
The Multi-Spectral Imager (MSI) onboard of the EarthCARE satellite will provide the information needed for describing the cloud and aerosol properties in the across-track direction complementing the measurements from the cloud profiling radar, atmospheric lidar and broadband radiometer. The accurate discrimination between clear and cloudy pixel is an essential first step. Therefore, the cloud mask algorithm provides a cloud flag, cloud phase and cloud type product for the MSI observations.