Short term teleconnections associated with an individual tropical cyclone

Abstract

The short term teleconnections associated with an individual western Pacific tropical cyclone have been investigated using an atmospheric general circulation model. The general strategy was to use the GCM, in combination with several tropical cyclone bogusing procedures, to isolate the effects on the global circulation of the tropical cyclone. The bogusing procedures were used to alter the tropical cyclone in the initial conditions for the model. The primary modeling experiments involved using the tropical cyclone bogusing procedures to include or exclude the tropical cyclone from the initial conditions. The difference between model results that contained the tropical cyclone and those that did not were used to analyze the global response to the tropical cyclone. These results showed a strong and persistent teleconnection response in the extratropical northern hemisphere. This response was mainly evident in slowly propagating Rossby waves in the 200 mb height field. Examinations of the teleconnection mechanisms showed that the east Asian-north Pacific jet played a major role in the development of the teleconnection. In particular: (1) the 200 mb height responses showed a consistent relationship with the jet; (2) the jet acted as a waveguide for the Rossby wave energy; and (3) the regions of potential barotropic instability which flank the jet were often colocated with areas of wave amplification.