Development of the stretch-atmosphere and ocean model to study air-sea interaction associated with tropical cyclone

The tropical cyclones approached near Japan bring the large impacts on our lives. While the track of tropical cyclone is mainly controlled by wind fields associated with the Pacific high, development is influenced by heat flux from that oceans. Recently, global nonhydrostatic atmospheric model (Nonhydrostatic Icosahedral Atmospheric Model, NICAM) is used to simulate the tropical cyclones or characteristics of deep convection. However, to simulate the tropical cyclones more reality, we should develop the atmosphere-ocean coupling model. We select the stretched-version NICAM (Tomita et al., 2008) as an atmospheric model and also select the CCSR Ocean Component Model (COCO) as an ocean model. The Stretch-NICAM saves computational resources by focusing on a specific region at high resolution. The horizontal resolution becomes coarser for the region outside the target region, but in this study we are only interested in the local results within the target region. The horizontal spacing of stretched-version NICAM and COCO is about 7 km and 1 degree grid, respectively. The horizontal grid configuration is difference between stretched-version NICAM and COCO. Here we insert the coupler model (called Jcup) between the two models and exchange of fluxes are performed in Jcup every 1 hr. The initial condition of the NICAM is prepared by NCEP Tropospheric Analysis data. Initial data of COCO is prepared by COCO-3D data. Here, COCO-3D data is calculated by periodically forcing by ERA-interim data. In this study, we chose the tropical cyclone generated at 28 August 2004 near Japan and investigate the air-sea interaction associated with the tropical cyclone. The model integration is performed with 7 days. We also perform the NICAM integration (not coupled) calculation to investigate the influence of the ocean. Here, we select the some types of initial condition of the sea surface temperature data. To compare the real ocean, we also use the 4-dimensional Ocean Reanalysis dataset (FORA) and Argo floats data. Our new model shows that the reduction of the sea surface temperature associated with tropical cyclone is large about 1 K compared with FORA data. In the presentation, we will show the results about the boundary layer and state in the sea.