Item

Abstract

In common weather and climate models rime-splintering is the only included secondary ice production process. In addition, assumed concentrations of cloud condensation nuclei or cloud droplet number as well as of ice-nucleating particle are higher in standard models than for Arctic environments. This can lead to a misrepresentation of phase distribution in and precipitation from Arctic mixed-phase clouds. During the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) a holographic probe mounted on a tethered balloon took in-situ measurements of ice crystal and cloud droplet number and mass concentrations in Svalbard, Norway, during fall 2019 and spring 2020. In this study, we use the Weather Research and Forecasting (WRF) model to simulate selected case studies from this campaign in a high vertical and spatial resolution. We test the performance of different microphysical parametrizations and apply a new state-of-the-art secondary ice parametrization. We find that the degree of agreement with observations highly depends on the chosen microphysics settings and that for a case with a lot of observed secondary ice production modeled ice crystal concentrations stay below the measured values even after adding new secondary ice processes to the model. In addition to performing sensitivity studies regarding microphysical parametrizations and the direct comparison with observations from the balloon, we analyze the spatial variability of cloud phase and its dependence on different meteorological parameters.