An Observational Study of the Extremely Heavy Rain Event in Northern Vietnam during 30 October-1 November 2008

• DOI: 10.2151/jmsj.2011-a23
• Publication Date: 2011-05-05T06:06:11Z
• Authors: Peiming WU; Yoshiki FUKUTOMI; Jun MATSUMOTO
• Keywords: Subtropical ridge

An extraordinarily heavy rain event occurred in northern Vietnam from 30 October to 1 November 2008. The three consecutive days of extremely resulted the worst flooding Hanoi, capital Vietnam, and its environs 24 years. Results analysis Japan Meteorological Agency Climate Data Assimilation System (JCDAS) re-analysis data show that a synoptic-scale tropical wave disturbance formed over South China Sea traveled northwestward eastern coast Indochinese Peninsula, brought rainfall Vietnam. In mid-latitudes, belt surface high extended southeastward western Mongolia East Sea, causing persistent northeasterly monsoonal flow on south-eastern edge along southern China. worked together with disturbance, creating strong low-level wind convergence Examination structure revealed meridional cyclonic vorticity vertically approximately 300 hPa, maximum fluctuations occurring at 800-600 hPa layer shows nearly vertical height. A remarkable feature atmosphere is large increases equivalent potential temperature upper troposphere higher than about 500 southerly winds greater 15 m s-1 300-150 layers for question. conclusion, which Asian winter monsoon, caused extreme event.