Assimilation of Global Positioning System Radio Occultation Observations into KIAPS-LETKF system

Korea Institute of Atmospheric Prediction Systems (KIAPS) has successfully implemented Local Ensemble Transform Kalman Filter (LETKF; Hunt et al. 2007) data assimilation system to KIAPS-Global Model (KIAPS-GM) that has fully unstructured quadrilateral meshes based on the cubed-sphere grid within the KIAPS-LETKF system, we have assimilated conventional data as well as various remote sensing observations such as AMSU-A, IASI, GPS RO, which an observation preprocessing team at KIAPS has processed. In particular, operational NWP centers (e.g. Met Office and ECMWF) have demonstrated a significant impact of GPS RO, despite its relatively low observation number, when compared with the amount of data that is already assimilated (Healy et al., 2005; Healy and Thepaut, 2006). Thus, we will present our framework of GPS RO data assimilation within KIAPS-LETKF system and discuss its performance at the conference.