Seminar 10 (January 29, 2025) of the CleanCloud series. 

Speaker is Dr. Otto Hasekamp (SRON - Netherlands Institute for Space research).

Abstract:
On February 8, 2024 the NASA Plankton, Aerosol, Cloud & ocean Ecosystem (PACE) mission has been launched with onboard the Ocean Color Instrument (OCI), the Spectropolarimeter for Planetary Exploration-one  (SPEXone), and the Hyperangular Rainbow Polarimeter-2 (HARP-2). The three instruments on PACE provide a wealth of information on aerosol and cloud properties and are expected to bring important new pieces of information to better quantify the cooling effect on climate due to aerosol-radiation interactions (ARI) and aerosol-cloud interactions (ACI). This seminar provides an overview of the (almost) first year of PACE observations with focus on the two polarimeters on PACE (SPEXone, HARP-2). We will show a global view of aerosol size, absorption, and composition from SPEXone and discuss the potential of SPEXone to provide suitable proxies for Cloud Condensation Nuclei (CCN). From HARP-2, we will show observations of cloud droplet size distributions retrieved from polarization measurements in the cloud-bow. Finally, we discuss strategies to use PACE data for constraining the Effective Radiative Forcing (ERF) in climate models.