Interaction of Typhoon Shanshan (2006) with the Midlatitude Trough from both Adjoint-Derived Sensitivity Steering Vector and Potential Vorticity Perspectives
Resource
Monthly Weather Review 137 (3): 852-862
Journal
Monthly Weather Review
Journal Volume
137
Journal Issue
3
Pages
852-862
Date Issued
2009
Date
2009
Author(s)
Abstract
Targeted observation is one of the most important research and forecasting issues for improving tropical cyclone predictability. A new parameter [i.e., the adjoint-derived sensitivity steering vector (ADSSV)] has been proposed and adopted as one of the targeted observing strategies in the Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR). The ADSSV identifies the sensitive areas at the observing time to the steering flow at the verifying time through the adjoint calculation. In this study, the ADSSV is calculated from the nonlinear forecast model of the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5) and its adjoint to interpret the dynamical processes in the interaction between Typhoon Shanshan (2006) and the midlatitude trough. The ADSSV results imply that high-sensitivity regions affecting the motion of Typhoon Shanshan are located at the edge of the subtropical high and the 500-hPa midlatitude trough over northern central China. These ADSSV signals are in very good agreement with the quantitative evaluation based on the potential vorticity (PV) diagnosis. The vertical structure of the ADSSV is also shown for more physical insights into the typhoon-trough interaction. The maximum ADSSV occurs at 800-500 hPa to the southeast of Shanshan (associated with the subtropical high), while distinct ADSSV signals are located upstream of the storm center at about 500-300 hPa (associated with the mid- to upper-tropospheric midlatitude trough). Overall, it is demonstrated that the ADSSV features can well capture the signal of the large-scale trough feature affecting the motion of Shanshan, which can also be well validated from the PV analysis. © 2009 American Meteorological Society.
Other Subjects
Adjoints; Dynamical process; FORECAST model; High-sensitivity; Mesoscale model; Midlatitudes; National center for atmospheric researches; New parameters; Pennsylvania State University; Potential vorticity; Quantitative evaluation; Sensitive area; Steering flow; Steering vector; Storm center; Targeted observing; Tropical cyclone; Typhoon surveillance; Vertical structures; Climatology; Tropics; Vorticity; Water wells; Weather forecasting; Hurricanes; climate prediction; midlatitude environment; modeling; potential vorticity; tropical cyclone; typhoon; weather forecasting
Type
journal article
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