Lanzhou Institute of Plateau Atmospheric Physics;
Meteorological Office;
Bracknell;
Berkshire;
UK;
Meteorological Office;
Bracknell;
Berkshire;
UKn this paper the differences between Meiyu and Baiu front in 1983 have firstly been analysed;
the trajectories of air on and to the north side of Meiyu and Baiu fronts during the Meiyu period have then been traced;
and the forecasting and simulating of 4 sets of Meiyu onset of the year have finally been run utilizing the global model at UK Me-leorological Office. The results show: 1) Meiyu fronts are different from Baiu ones in temperature;
humidity and stratification fields in lower atmosphere;
and the possibly reasons for it are explained. 2) The Bay of Bengal is the main moisture source for Meiyu front;
the South China Sea and the Pacific;
for Baiu ones;
and some existed arguments on it are also discussed. 3) The onset of Meiyu and its rainfall and rain belts are sensitive to the Tibetan Plateau;
and the water vapour conditions over the Bay of Bengal and the South China Sea;
but not sensitive to the SST over the equatorial area or to the East of Japan.;
Plateau; rainfall; moisture; north; Tibetan; forecasting; humidity; stratification; utilizing; possibly;