Variability of aerosol-cloud interactions induced by different cloud droplet nucleation schemes

Variability of aerosol-cloud-interactions in a climate model due to different cloud droplet nucleation schemes are investigated, and the effects of parameter optimization on simulated clouds and climate variables for a present-day climate are also analyzed. The ECHAM5/Messy chemistry-climate model EMAC is used for such task and cloud microphysical and macrophysical properties and climate variables are examined from the simulations for the present-day climate. We optimize the model performance via tuning parameters for each of several different model configurations. The optimization processes partly control the hydrological budget and cloud optical properties and seem to improve the performance of simulating climate variables, based on the global averaged values. However, the parameter optimization dose not always guarantee better performances; some variables are shown to decreases in the spatial correlation with observations after tuning. The optimizations seem to attenuate the regional sensitivity of different CCN activation schemes and thereby reducing its influences on local climate.

D. Y. C. acknowledges support from the Korea Meteorological Administration Research and Development Program under Grant KMI2018-03511.