Abstract
Abstract. In association with the passage of a Tropical Cyclone (TC) around Japan, the secondary circulation in the region from the outer side to the center was investigated in detail by two separately located L-band wind profilers and the rawinsonde observations from 1 to 2 October 2002, for the first time. As the wind profilers can observe wind fields not only within rainbands but also in between, the mesoscale wind circulation including the vertical wind component in wide areas from the lower layer to the upper layer was investigated. While the TC center approached the profiler stations, several rainbands associated with the TC subsequently passed. Relatively warm, moist inflow with a cyclonic rotation was observed in the lower-troposphere while the TC center approached. The inflow reached the inside of the main rainband where the updraft was observed. Above 5-km height (with temperature below 0°C), outflow and weak downdraft corresponding to falling frozen particles were observed. It is considered that the frozen particles formed precipitating clouds mainly in the outer rainband region. The continuous wind circulation transported water vapor from the lower troposphere to the upper troposphere via the vicinity of TC center. On the other hand, after the passage of the TC center, the developed rainband passed, which was located in the south and southwest quadrant of the TC. It is suggested with the profilers' data that the rainband was intensified mainly by warm and moist outflow below 3-km height.
Highlights
BackgroundObservational studies of Tropical Cyclones (TC) by surface meteorological instruments, balloons, airborne (Jorgensen, 1984a, b; Marks et al, 1987; Powell, 1990a, b; Ryan et al, 1992; Harr and Elsberry, 1996) and ground-based Doppler radars (Sakakibara et al, 1985; Ishihara et al, 1986; Tabata et al, 1992) have made substantial contributions to the understanding of TC’s structure and dynamics. Jorgensen (1984a, b) reported the precipitating clouds of eyewall, a stratiform rain region, and rainbands, which were observed by an airborne radar mainly within a radius of 150 km from TC center
Marks et al (1987) pointed out that the primary circulation was characterized by a core of maximum tangential wind, while the secondary circulation in radius-height cross section was characterized by a lower tropospheric layer with inward directed flow and a layer of intense radial outflow from the eyewall concentrated at upper levels
Outflow and weak downdraft were seen above 5 km height
Summary
Observational studies of Tropical Cyclones (TC) by surface meteorological instruments, balloons, airborne (Jorgensen, 1984a, b; Marks et al, 1987; Powell, 1990a, b; Ryan et al, 1992; Harr and Elsberry, 1996) and ground-based Doppler radars (Sakakibara et al, 1985; Ishihara et al, 1986; Tabata et al, 1992) have made substantial contributions to the understanding of TC’s structure and dynamics. Jorgensen (1984a, b) reported the precipitating clouds of eyewall, a stratiform rain region, and rainbands, which were observed by an airborne radar mainly within a radius of 150 km from TC center. Marks et al (1987) pointed out that the primary circulation was characterized by a core of maximum tangential wind, while the secondary circulation in radius-height cross section was characterized by a lower tropospheric layer with inward directed flow and a layer of intense radial outflow from the eyewall concentrated at upper levels These characteristics agree well with theoretical studies by Shapiro and Willoughby (1982) and others. A positive vertical wind is considered to be an updraft, but a negative wind cannot be identified as either a downdraft or falling rain particles Even admitting this defect, the data are important to examine characteristics of water circulation associated with TC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
