title: Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers.
abstract: Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day.
authors.affiliation: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; daniel.rosenfeld@huji.ac.il.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rosenfeld
authors.affiliation: Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD 20740; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740; State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China;
authors.forename: Youtong
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
authors.forename: Eyal
authors.initials: E
authors.lastname: Hashimshoni
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany; Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany;
authors.forename: Mira L
authors.initials: ML
authors.lastname: Pöhlker
authors.affiliation: Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305;
authors.forename: Anne
authors.initials: A
authors.lastname: Jefferson
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany;
authors.forename: Christopher
authors.initials: C
authors.lastname: Pöhlker
authors.affiliation: Meteorological Institute of Shaanxi Province, Xi'an 710015, China;
authors.forename: Xing
authors.initials: X
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China; Meteorological Institute of Shaanxi Province, Xi'an 710015, China;
authors.forename: Yannian
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Meteorological Institute of Shaanxi Province, Xi'an 710015, China;
authors.forename: Guihua
authors.initials: G
authors.lastname: Liu
authors.affiliation: Meteorological Institute of Shaanxi Province, Xi'an 710015, China;
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yue
authors.affiliation: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
authors.forename: Baruch
authors.initials: B
authors.lastname: Fischman
authors.affiliation: Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD 20740; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740; State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China;
authors.forename: Zhanqing
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
authors.forename: David
authors.initials: D
authors.lastname: Giguzin
authors.affiliation: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
authors.forename: Tom
authors.initials: T
authors.lastname: Goren
authors.affiliation: Physics Institute, University of Sao Paulo, Sao Paulo 05508-090, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Artaxo
authors.affiliation: Physics Institute, University of Sao Paulo, Sao Paulo 05508-090, Brazil.
authors.forename: Henrique M J
authors.identifier: 0000-0002-4027-1855
authors.initials: HM
authors.lastname: Barbosa
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany; Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany;
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pöschl
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany;
authors.forename: Meinrat O
authors.identifier: 0000-0003-1968-7925
authors.initials: MO
authors.lastname: Andreae
keywords: CCN concentrations; cloud−aerosol interactions; convective clouds; satellite remote sensing