[AAS02-P05] Asymmetrically Intensifying Processes of a Category 4 Super Typhoon Lan (2017) during High Vertical Wind Shear
Keywords:Typhoon, numerical model
The typhoon simulated in the 1dO experiment successfully achieved the MCP of 910 hPa at 29.5°N, exhibiting strong asymmetric precipitation pattern as observed by the satellites. The intensification processes were accompanied by rapid developments of the strong winds and warm core in the low-levels. The strong northeast VWS forced to tilt the storm axis to downshear side (northeast) and, in the downshear quadrants, tall, intense and upstanding eyewall updrafts (CBs) formed from the low-level convergence of the storm travelling northeastward with a relatively fast translation speed of 10 m s–1. Meanwhile, dry subsidence from the upper-levels intensified the low-level warm core in the upshear side of the eye. Despite the inner-core convection and precipitation exhibited strong asymmetric structures, the axisymmetricity of the storm circulation was maintained in the mid-to-low levels and abundant water vapor enclosed in the eye allowed to develop CBs around the radius of the maximum wind speeds. Although the FO storm overestimated the MCP of 879hPa, the similar asymmetric patterns in precipitation and convection were also found in the FO storm. The results indicated that the storm structures of typhoon Lan would be less sensitive to the SST-cooling effect.