@Article{BragaERAFFPHJKLMPSVWWPP:2021:ClMoMe,
               author = "Braga, Ramon Campos and Ervens, Barbara and Rosenfeld, Daniel and 
                         Andreae, Meinrat O. and F{\"o}rster, Jan-David and F{\"u}tterer, 
                         Daniel and Pardo, Lianet Hern{\'a}ndez and Holanda, Bruna A. and 
                         Jurkat-Witschas, Tina and Kr{\"u}ger, Ovid O. and Lauer, Oliver 
                         and Machado, Luiz Augusto Toledo and P{\"o}hlker, Christopher and 
                         Sauer, Daniel and Voigt, Christiane and Walser, Adrian and 
                         Wendisch, Manfred and P{\"o}schl, Ulrich and P{\"o}hlker, Mira 
                         L.",
          affiliation = "{Max Planck Institute for Chemistry} and {Universit{\'e} Clermont 
                         Auvergne} and {The Hebrew University of Jerusalem} and {Max Planck 
                         Institute for Chemistry} and {Max Planck Institute for Chemistry} 
                         and {German Aerospace Center (DLR)} and {Max Planck Institute for 
                         Chemistry} and {Max Planck Institute for Chemistry} and {German 
                         Aerospace Center (DLR)} and {Max Planck Institute for Chemistry} 
                         and {Max Planck Institute for Chemistry} and {Instituto Nacional 
                         de Pesquisas Espaciais (INPE)} and {Max Planck Institute for 
                         Chemistry} and {German Aerospace Center (DLR)} and {German 
                         Aerospace Center (DLR)} and {German Aerospace Center (DLR)} and 
                         {University of Leipzig} and {Max Planck Institute for Chemistry} 
                         and {Max Planck Institute for Chemistry}",
                title = "Cloud droplet formation at the base of tropical convective clouds: 
                         closure between modeling and measurement results of 
                         ACRIDICON–CHUVA",
              journal = "Atmospheric Chemistry and Physics Discussion",
                 year = "2021",
               volume = "21",
                pages = "17513--17528",
             abstract = "Aerosolcloud interactions contribute to the large uncertainties in 
                         current estimates of climate forcing. We investigated the effect 
                         of aerosol particles on cloud droplet formation by model 
                         calculations and aircraft measurements over the Amazon and over 
                         the western tropical Atlantic during the ACRIDICONCHUVA campaign 
                         in September 2014. On the HALO (High Altitude Long Range Research) 
                         research aircraft, cloud droplet number concentrations (Nd) were 
                         measured near the base of clean and polluted growing convective 
                         cumuli using a cloud combination probe (CCP) and a cloud and 
                         aerosol spectrometer (CAS-DPOL). An adiabatic parcel model was 
                         used to perform cloud droplet number closure studies for flights 
                         in differently polluted air masses. Model input parameters 
                         included aerosol size distributions measured with an ultra-high 
                         sensitive aerosol spectrometer (UHSAS), in combination with a 
                         condensation particle counter (CPC). Updraft velocities (w) were 
                         measured with a boom-mounted Rosemount probe. Over the continent, 
                         the aerosol size distributions were dominated by accumulation mode 
                         particles, and good agreement between measured and modeled Nd 
                         values was obtained (deviations . 10 %) assuming an average 
                         hygroscopicity of \κ \∼ 0.1, which is consistent with 
                         Amazonian biomass burning and secondary organic aerosol. Above the 
                         ocean, fair agreement was obtained assuming an average 
                         hygroscopicity of \κ \∼ 0.2 (deviations . 16 %) and 
                         further improvement was achieved assuming different 
                         hygroscopicities for Aitken and accumulation mode particles 
                         (\κAit = 0.8, \κacc = 0.2; deviations . 10 %), which 
                         may reflect secondary marine sulfate particles. Our results 
                         indicate that Aitken mode particles and their hygroscopicity can 
                         be important for droplet formation at low pollution levels and 
                         high updraft velocities in tropical convective clouds.",
                  doi = "10.5194/acp-21-17513-2021",
                  url = "http://dx.doi.org/10.5194/acp-21-17513-2021",
                 issn = "1680-7367",
             language = "en",
           targetfile = "braga_cloud.pdf",
        urlaccessdate = "28 abr. 2024"
}