Recent research and development progress of physical processes in the Korean Integrated Model

The Korea Integrated Model (KIM), developed by Korea Institute of Atmospheric Prediction Systems (KIAPS) from 2011 to 2019 for Korea's own numerical weather prediction (NWP) model, has been in operation at Korean Meteorological Administration (KMA) since April 2020. The first operational version of KIM is v3.5, and it has been updated four times (v3.5a in June 2020, v3.6 in October 2020, v3.6a in April 2021, v3.7 in December 2021) by improving and modifying the data assimilation system and model physical processes. In this study, we provide a brief overview of the update of physical processes so far and introduce recent research and development progress in KIM physics for the next version update. The major modifications on physical processes are optimization of some empirical parameters included in convective parameterization scheme using micro generic algorism, improvement of initial condition of snow, and improvement of ice microphysical properties, updated in the versions of 3.5a, 3.6a, and 3.7, respectively. Recently we mitigate the sea ice concentration threshold from 0.5 to 0.15 to alleviate warm biases in the marginal ice zone. In addition, we modify the concentration of cloud condensation nuclei in sea ice regions to reduce low tropospheric polar cold biases, major systematic biases in northern summer season, through the interaction between the cloud and radiation. Finally, a bug found in the process of cloud formation by condensation in cloud prognostic scheme is fixed, which significantly improves moisture biases in the low tropics and mid-latitudes.