The Community Atmosphere Model (CAM-SE) is ported, redesigned, and scaled to the full system of the Sunway TaihuLight, and provides peta-scale climate modeling performance. We refactored and optimized the complete code using OpenACC directives at the first stage. A more aggressive and finer-grained redesign is then applied on the CAM, to achieve finer memory control and usage, more efficient vectorization and compute-communication-overlapping. The well-tuned program running on the powerful TaihuLight system enables us to perform, to our knowledge, the first simulation of the complete lifecycle of hurricane Katrina, and achieves close-to-observation simulation results for both track and intensity.