Simulation of a tropical cyclone in an atmospheric general circulation model
The realistic simulation of tropical cyclones in global climate models is still a challenge. The grids of such models typically have a mesh size of more than 50km. The core of a tropical cyclone exhibits on the other hand a diameter of similar or smaller magnitude. Despite this problem, it is possible to reasonably simulate the genesis process, as well as the migration of the storm.
Differences between various models are investigated in the context of the model intercomparison project DCMIP (Dynamical Core Model Intercomparison Project). The video shows a simulation that was performed with the atmospheric general circulation model PUMA. The green surface encloses the volume in which the wind speed is larger than 17m/s, while the red lines depict isolines at the ocean surface. One can detect a rapid storm intensification, which is accompanied by an enlargement of the green surface and an increased concentration of the isolines. At the same time, the tropical cyclone migrates on a typical track in north-northwest direction. The emergence of a further spiral-shaped green volume in the upper part of the storm results from the outflow that has a reverse anticyclonic curvature.