East Asia and Western Pacific METEOROLOGY AND CLIMATE

14
OVERVIB/V CF MEI-YU RESEARCH IN TAIWAN
George Tai-Jen Qien
Department of Atanospheric Science
National Taiwan University
Taipei, Taiwan.
ABSTRACT
Mei-Yu (or Baiu) is a unique regional weather and climate
phenomenon over East Asia and the western North Pacific. It occurs in
the period of late spring to early surmer when the circulation regime
over the area changes from the northeast monsoon in winter to the
southwest monsoon in summer. The mean position of this phenomenon
migrates northward with time. It occurs over southern China and the
Taiwan area in the period of mid-may to mid-June. The main purpose of
this paper is to review and look ahead the Mei-Yu research work that
have been done and would be done by Taiwan meteorologists. Research
work for the Mei-Yu over southern China and the Yangtz River Basin was
mostly not included.
The primary focus of this paper is the basic and applied
research on various features of Mei-Yu on different time and space
scales. Oily a very small portion of this paper is devoted to the
aspect of forecast research. However, the current forecast skill of
the Central V\feather Bureau in heavy rainfall was evaluated and
research work needed for improving the skill were suggested.
The first part of this paper discussed the existence and
importance of Nfei-Yu in Taiwan, \\brk on synoptic and climatological
aspects of the Ivfei-Yu system was then reviewed. Studies of interannual
variability of Mei-Yu were also included. Investigations of the
characteristics of mesoscale convective systems (KCS's) as well as the
environmental conditions and mesoscale triggering mechanisms for the
formation and evolution of NCS's were swmarized. Research of
mesoscale circulation systems in the .Mei-Yu season, such as the Mei-Yu
front, low-level jet (LLJ), mesolow and outflow boundary, and
topographical effect was also discussed. Finally, the field-phase of
the "Taiwan Area Mssoscale Experiment (T/MEX)" were presented.