Abstract
Taiwan is a unique place to study typhoon-orography interactions. On the average, four typhoons encounter the high Central Mountain Range (CMR) per year. This study analyzes the hourly surface wind and pressure structure over the Taiwan area during typhoon Nadine (1971) and typhoon Betty (1961) .The results show the center of Nadine passed over the CMR continuously. On the other hand, secondary circulation and a secondary low formed over western Taiwan when typhoon Betty moved close but still to the east of the CMR. The original center and the secondary circulation/low moved in different directions. When the original center of Betty weakened over the east side of the CMR, the secondary circulation/low became the dominating system. This situation is very different from a typhoon track over an open ocean. The formation of the secondary circulation/low started from a pronounced wind shift from northerly to southwesterly over southwestern Taiwan. The southwesterly wind blew against the CMR and induced a ridge in the southern part of the existing lee trough. If the ridge was strong enough, the low pressure zone over the west side of the CMR was separated from the original center over the east side. The southwesterly near the CMR was further deflected to northward by the mountain to form a cyclonic circulation over the west side of the CMR.
Highlights
Prediction of typhoon tracks and intensities is one of the major forecasting problems in Taiwan
This paper has shown the detailed surface wind and pressure distributions over the Taiwan area when typhoons Nadine in 1971 and Betty in 1961 were invading Taiwan
The center of Nadine passed over the Central Mountain Range (CMR) continuously an orography-induced local ridge/trough was found
Summary
Prediction of typhoon tracks and intensities is one of the major forecasting problems in Taiwan. The results of Bender et al (1987) and Yeh and Elsberry (1993) showed similarity, but both conclusions on whether the secondary low can move and develop to replace the original center are different from the earlier observations (e.g., Brand and Blelloch, 1974; Wang, 1980). Yeh and Elsberry (1993) noticed that under the significant topography influence, a simple balanced relationship between the winds and pressure fields such as the earlier observational studies applied is not valid especially in the area nenr the mountain It is worthwhile re-examining the detailed structure of typhoon-CMR interaction from surface observations.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
