Characteristics and environmental properties of the intensification and evolution of Typhoon Haiyan (2013)

Abstract:

Typhoon Haiyan (2013) caused devastating damage over the Philippines. Based on the best-track data, the maximum intensity of Haiyan during its lifetime reached 895 hPa as the central pressure and 65 m/s as the sustained wind speed. Representation of the intensity of such super-intense tropical cyclones in numerical simulations is a challenging issue. This study investigates the quantitative representations of the intensification of Typhoon Haiyan (2013) in numerical simulations at the horizontal resolutions on the order of 1 km. In the control run, we successfully reproduced the intensification, evolution, and maximum intensity of Haiyan: the simulated minimum central pressure and maximum wind speed was 896.6 hPa and 67.2 m/s, respectively. If the computation of the 2nd domain was initiated 1-day later, the simulated typhoon failed to achieve that maximum intensity because of a slower intensification. If the nested domain was not ingested, the minimum central pressure in the 3-km run was 928.8 hPa. Nesting a finer-resolution domain (i.e., 333-m resolution) reproduced the rapid intensification of the typhoon. We here examine the environmental CAPE amount which is calculated along the TC track within the 100-km distance from the TC center at the time 12-hour before when the TC is located. The analysis on convective available potential energy (CAPE) before the rapid intensification indicates that the environmental CAPE accumulates before the intensification along the typhoon track. Resolving convective development in the inner core of the typhoon at its early stage and the existence of a sufficient amount of convective instability in the environment along the TC track are keys to quantitative representation of the evolution and intensity of Typhoon Haiyan (2013). From the analyses, the accumulation of CAPE before the initiation of rapidly intensifying phase of tropical cyclones put forth by Miyamoto and Takemi (2013) seems to play a role in the intensification of Typhoon Haiyan by providing a favorable condition. The quantitative representation of the evolution and intensity of Typhoon Haiyan led to a successful simulation of the storm surge induced by Haiyan over Leyte Gulf (Mori et al. 2014).