Abstract 091

Abstract ID: 091

Impacts of an Atmosphere-Ocean Coupling in the Korean Integrated Model (KIM)

Lead Author: Eunjeong Lee
Korea Institute of Atmospheric Prediction Systems (KIAPS), South Korea

Keywords: atmosphere-ocean coupling, Korean Integrated Model (KIM), extended-range forecasts

Abstract: The Korean Integrated Model (KIM) was developed with an aim for global weather forecasting by the Korea Institute of Atmospheric Prediction Systems (KIAPS), which has become the operational model of the Korea Meteorological Administration (KMA) since April 2020. The next step is attempting to improve predictability on an extended range. For this purpose, an earth system-atmosphere interaction must be considered in the framework of KIM so an atmosphere-ocean coupling has been developed. Due to this, it is expected that KIM will be able to consider even the physical processes related to air-ocean interactions in the predictions on the time scales beyond the medium-range. The Nucleus for European Modelling of the Ocean (NEMO) version 4.0 with the eddy-permitting resolution was coupled with the atmospheric component of KIM through a coupler based on the Model Coupling Toolkit (MCT). In addition, in the updated version, a method to ensure consistency between the model components was developed, and the surface layer parameterization was modified, which results in elaborating the coupling. The feasibility of the coupling was proved from an assessment of medium-range forecasts and seasonal predictions, through the comparison of simulations without/with the coupling (unCPL/CPL). These results suggest that the coupling can secure model stability as well as affect performance improvement in global forecasts. For example, the results against ERA5 reanalysis data showed that the CPL effectively mitigates the systematic biases existing in the lower troposphere over the middle and high latitudes and remarkably improves the predictability of the upper tropospheric temperature. Besides, it was observed that the location of the tropical precipitation was improved in CPL by more accurate moisture convergence, compared to unCPL with an observed sea surface temperature forcing. Furthermore, we are planning to evaluate the characteristics of the KIM coupled model in the extended-range forecasts.

Myung-Seo Koo (KIAPS)