Abstracts for the 6th International GAME Conf.
3-5 December 2004
Kyoto Japan
Mesoscale Structure and Along-Front Variation of a Meiyu Front and Associated Precipitation Observed in the Downstream Region of the Yangtze River
Biao Geng (1), Hiroyuki Yamada (1), Krishnareddigari Krishna Reddy (1), Hiroshi Uyeda (4), Yasushi Fujiyoshi (5)
(1) Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology
(4) Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology/Nagoya University
(5) Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology/Hokkaido University
Data from Doppler radars and intensified rawinsonde and surface measurements were used to analyze the detailed mesoscale structure of a Meiyu front and associated precipitation systems. The front was observed in the downstream region of the Yangtze River on 21 June 2002. It was oriented in a southeast-northwest direction and was northeastward-sloping. The surface front was well defined by the intense horizontal gradient of the virtual potential temperature and there was nearly a 180-degree shift in wind direction across the front.
Detailed analyses show that the front could be divided into two parts according to distinct differences in the cross-frontal structure and the organization of the frontal precipitation. The eastern segment of the front moved slowly northward. It was shallow, less than 1 km in depth. A southwesterly low-level jet was identified ahead of the front. Precipitation system in this region was organized with new convection successively developing south of the front, moving across the front toward the north, and becoming stratiform precipitation behind the front. In contrast to the eastern segment, the western segment of the front moved slowly southward. The frontal surface reached as high as 6 km and its slope was much steeper in the leading edge. Instead of the prefrontal low-level jet, a northeasterly rear-inflow jet was found behind the front at middle levels. Convection evolved close to the leading edge of the front and little stratiform precipitation was found behind the front.
Based on the observational results, important processes related to the along-front variability of the frontal circulation and associated precipitation were discussed.
Submittal Information
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Institute of Observational Research for Global Change, Japan Agency for Marine-Earth Science and Technology | |
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3173-25 Showa-machi Kanazawa-ku, Yokohama-city Kanagawa, 236-0001 | |
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