Comparisons of Cloud Microphysical Properties Retrieved from Different Algorithms during Aerosol Transport Events

Multi-spectral data from the MODerate resolution Imaging Spectroradiometer (MODIS) onboard the Terra spacecraft are used to derive cloud optical thickness and effective particle radius using the algorithm of Nakajima and Nakajima (1995). Microphysical cloud properties are retrieved during strong aerosol events from biomass burning to better understand the actual effects of cloud-aerosol interactions. Rosenfeld (1999) observations have shown not only that cloud microphysical properties are affected by the presence of smoke aerosols from burning vegetation but also that precipitation can be consequently suppressed. A key step for the understanding of these effects is the comparison of the retrieved cloud parameters with independent sources. In the present work the retrieved quantities (Costa et al., 2004) are compared with space and time coincident cloud optical thickness and effective particle radius from the MODIS official cloud product (King et al., 1998) and intensive measurement campaigns. Low Earth Orbit (LEO) satellite sensors are normally targeted for these studies, as it is in the present work, since they were the only ones that supplied the necessary multi-spectral measurements. The launch of Geostationary Earth Orbit (GEO) platforms with sensors like the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on METEOSAT Second Generation (MSG) opens up the possibility of extending cloud and aerosol retrievals to the GEO orbit. This will greatly improve the frequency of measurements, allowing for global monitoring of cloud properties. An extension of the study in view of the upcoming availability of MSGSEVIRI multi-spectral data is conceived.