@Article{BragaERAFFPHJKLMPSVWWPP:2021:ClDrNu,
               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, 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 number closure for tropical convective clouds during 
                         the ACRIDICON–CHUVA campaign",
              journal = "Atmospheric Chemistry and Physics Discussion",
                 year = "2021",
               volume = "2021",
                pages = "1--17",
             abstract = "The main objective of the ACRIDICON-CHUVA (Aerosol, Cloud, 
                         Precipitation, and Radiation Interactions and Dynamics of 
                         Convective Cloud SystemsCloud Processes of the Main Precipitation 
                         Systems in Brazil: A Contribution to Cloud Resolving Modeling and 
                         to the Global Precipitation measurements) campaign in September 
                         2014 was the investigation of aerosol-cloud-interactions in the 
                         Amazon Basin. Cloud properties near cloud base of growing 
                         convective cumuli were characterized by cloud droplet size 
                         distribution measurements using a cloud combination probe (CCP) 
                         and a cloud and aerosol spectrometer (CAS-DPOL). In the current 
                         study, an adiabatic parcel model was used to perform cloud droplet 
                         number (Nd) closure studies for several 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 speeds (w) were measured near cloud base 
                         using a boom-mounted Rosemount model 858 AJ probe. To compare to 
                         model predictions, measured Nd and w were statistically matched 
                         based on equal percentiles of occurrence. Reasonable agreement 
                         between measured and predicted Nd was achieved when a particle 
                         hygroscopicity of \κ\ ~\ 0.1 is assumed. 
                         Similar closure results were obtained when the variability in the 
                         particle number concentration was taken into account. We conclude 
                         that Nd can be predicted using a single \κ, and measured 
                         aerosol particle number concentration below cloud base when w is 
                         constrained based on measurements. In accordance with previous 
                         adiabatic air parcel model studies, the largest disagreements 
                         between predicted and measured Nd were found when updraft speeds 
                         were high (w\ >\ 2.5\ m\ s\−1) 
                         or in the presence of a bimodal aerosol size distribution. We show 
                         that simplifying assumptions on \κ might not be appropriate 
                         when the aerosol size distribution is comprised of both distinct 
                         Aitken and accumulation modes, as predicted Nd clearly deviate 
                         from measured ones at 
                         w\ \≥\ 1\ m\ s\−1 which 
                         points to a contribution of Aitken mode particles to Nd.",
                  doi = "10.5194/acp-2021-80",
                  url = "http://dx.doi.org/10.5194/acp-2021-80",
                 issn = "1680-7367",
             language = "en",
           targetfile = "braga_cloud.pdf",
        urlaccessdate = "09 maio 2024"
}