Downstream impacts due to the extratropical transition of tropical cyclones over the western North Pacific

• Main Author: Dea, Jonathan M.
• Other Authors: Harr, Patrick
• Published: Monterey, California. Naval Postgraduate School 2012
• Online Access: http://hdl.handle.net/10945/3551

Analysis of the eddy kinetic energy budget for four cases of extratropical transition (ET) with North Pacific tropical cyclones (TCs) is conducted. The cases compare varying ET and midlatitude flow characteristics. Each case was examined to determine the impacts of eddy kinetic energy generation and/or transfer on downstream development in the midlatitude circulation. Typhoon Tokage (October 2004) was a large TC that moved into a high-amplitude midlatitude circulation. Energetics analysis revealed that the ET of Tokage influenced the development of a deep trough over the central North Pacific before Tokage moved poleward and weakened transfer. Typhoon Banyan (July 2005) was a mid-summer case that influenced downstream development ultimately over the Aleutian Islands. Typhoon Guchol (August 2005) was a small TC that was dominated by midlatitude flow. However, the merger of Guchol with a midlatitude trough enabled development downstream of a separate trough. Typhoon Nabi was an intense TC that injected significant EKE into the midlatitude circulation during ET. Through downstream development, Nabi changed a zonal pattern over the North Pacific into an amplified pattern. These cases indicate that the ET process over the western North Pacific impacts the midlatitude circulation across the entire North Pacific basin.