Vicarious calibration of the JAXA Earth Clouds, Aerosols and Radiation Explorer (EarthCARE)/Multi-Spectral Imager (MSI) level 2 cloud product (MSI_CLP) and aerosol product (MSI_ARL)

Abstract. After launch in May 2024, the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite entered its orbit and commenced operations. In the early studies, it was reported that the initial version of Multi-Spectral Imager (MSI) level 1 data (MSI_RGR) had suffered some issues that compromised the data quality. To solve the issues of the MSI level 1 data, vicarious calibration is necessary particularly for the visible, near infrared, and shortwave infrared (VNS) bands. This paper described the vicarious calibration on MSI_RGR using the geostationary satellite Himawari-9 cloud retrieval as an intermediator. Our results based on the late revised version (vBa) of MSI_RGR verified the data quality improvement work by the ESA MSI level 1 team, which from slight overestimation (calibration coefficient of about 0.93) for the visible band and almost no overestimation or underestimation for near-infrared band in the case of cloud product. On the other side, for aerosol product, slight overestimation (calibration coefficient of about 0.92–0.93) for the visible band and slight underestimation (calibration coefficient of about 1.04–1.07) for near-infrared band. The calibration coefficients derived here will be used for further development of EarthCARE MSI products.