Kinetic Energy Budgets during the Rapid Intensification of Typhoon Rammasun (2014)

In this study, Typhoon Rammasun (2014) was simulated using the Weather Research and Forecasting model to examine the kinetic energy during rapid intensification (RI). Budget analyses revealed that in the inner area of the typhoon, the conversion from symmetric divergent kinetic energy associated with the collocation of strong cyclonic circulation and inward flow led to an increase in the symmetric rotational kinetic energy in the lower troposphere. The increase in the symmetric rotational kinetic energy in the mid and upper troposphere resulted from the upward transport of symmetric rotational kinetic energy from the lower troposphere. In the outer area, both typhoon and Earth’s rotation played equally important roles in the conversion from symmetric divergent kinetic energy to symmetric rotational kinetic energy in the lower troposphere. The decrease in the symmetric rotational kinetic energy in the upper troposphere was caused by the conversion to asymmetric rotational kinetic energy through the collocation of symmetric tangential rotational winds and the radial advection of asymmetric tangential rotational winds by radial environmental winds.