Short Term Teleconnections Associated with Western Pacific Tropical Cyclones
Abstract
The short term teleconnections arising from an individual tropical cyclone in the western Pacific were examined using a global operational data assimilation system and forecast model. In the data assimilation, the tropical cyclone was modified using a tropical cyclone bogusing procedure that other maintained the storm in, or eliminated the storm from, the model's initial conditions. These different initial conditions were used as the initial fields for several 20 day runs of the forecast model. These runs were used to simulate the global atmosphere with and without the tropical cyclone. The differences between these simulations were used to infer the global teleconnection response to the tropical cyclone. This response was dominated by a strong, quasi- stationary Rossby wave train that extended from east Asia across the North Pacific into North America. This wave train was initiated when an anticyclonic circulation formed near Japan as the tropical cyclone approached the east Asian jet. The anticyclone formation was primarily the result of the absolute vorticity advection by the divergent wind and vortex stretching (i.e., the Rossby wave source) associated with the tropical cyclone. The wave response continued to develop after this wave source, and the tropical cyclone itself, dissipated. This development was clearly seen in the growth and eastward propagation of Rossby wave energy across the mid latitude North Pacific and North America. The growth tended to be greater near areas of potential barotropic instability along the North Pacific jet, while the propagation tended to occur parallel to the jet. Teleconnections, Tropical cyclones, Tropical cyclone bogusing, Rossby wave source, Rossby wave train, Extended-range forecasting
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1994
- Accession Number
- ADA284032
Entities
People
- Cory A. Springer
Organizations
- Naval Postgraduate School