Analysis of feedbacks between nucleation rate , survival 1 probability and cloud condensation nuclei formation

10 Aerosol nucleation is an important source of particle number in the atmosphere. However, in 11 order to become cloud condensation nuclei (CCN), freshly nucleated particles must undergo 12 significant condensational growth while avoiding coagulational scavenging. In an effort to 13 quantify the contribution of nucleation to CCN, this work uses the GEOS-Chem-TOMAS 14 global aerosol model to calculate changes in CCN concentrations against a broad range of 15 nucleation rates and mechanisms. We then quantify the factors that control CCN formation 16 from nucleation, including daily nucleation rates, growth rates, coagulation sinks, 17 condensation sinks, survival probabilities, and CCN formation rates, in order to examine 18 feedbacks that may limit growth of nucleated particles to CCN. Nucleation rate 19 parameterizations tested in GEOS-Chem-TOMAS include ternary nucleation (with multiple 20 tuning factors), activation nucleation (with two pre-factors), binary nucleation, and ion21 mediated nucleation. We find that nucleation makes a significant contribution to boundary 22 layer CCN(0.2%), but this contribution is only modestly sensitive to choice of nucleation 23 scheme, ranging from 49-78% increase in concentrations over a control simulation with no 24 nucleation. Moreover, a two order-of-magnitude increase in the globally averaged nucleation 25 rate (via changes to tuning factors) results in small changes (less than 10%) to global 26 CCN(0.2%) concentrations. To explain this, we present a simple theory showing that survival 27 probability has an exponentially-decreasing dependence on the square of the condensation 28 sink. This functional form stems from a negative correlation between condensation sink and 29 growth rate and a positive correlation between condensation sink and coagulational 30