Diamond-NICAM-SPRINTARS: Validations and sample simulations

In this study, a regional model of the next generation global cloud-resolving model NICAM (Non-hydrostatic ICosahedral Atmospheric Model) (Tomita and Satoh, 2004) is developed and tested, which is called a Diamond-NICAM, and ran together with a transport model SPRINTARS (Spectral Radiation Transport Model for Aerosol Species) (Takemura et al, 2000) to simulate a transport of aerosols across the domain. This enables us to see the effects of warming, pollutants and urbanization to the changes in a local climate. Initially, an icosahedron-shaped NICAM can be described as twenty identical equilateral triangular-shaped panels covering the entire globe where grid points are at the corners of those panels. And new points are added at the middle of two adjacent points as its resolution is increased. Diamond-NICAM uses two of those original triangular shaped panels for its domain, and although the values at the outer boundary are replaced with an external data, it shares the same dynamical and physical processes with NICAM. Thus two models are directly comparable. For this presentation, our focus is on the validation of Diamond-NICAM, at first, through a direct comparison with NICAM (Fig.1). At the same time, effects of downscaling and internal nudging in the regional model are also discussed. In addition, sample simulations on the Fukushima radiation transport is conducted, recreating a map of radiation spread by analyzing a sulfate transport on the regional model. What we are hoping to achieve here is to verify an accuracy of running a finer resolution Diamond-NICAM-SPRINTARS model on transporting an aerosols, as detailed ground based data is available for the comparison.