Abstract
The oceanic mixed-layer response to a typhoon was studied using a three-dimensional model
in which the entrainment velocity was parameterized using only the vertical velocity shear entrainment
mechanism (DIM: Dynamic Instability Model). We simulated the response to Typhoon
#9019 in the area around the former Ocean Weather Station T (OWS-T) located south of Japan
(29°N, 135°E) during the period starting from September 15 through September 21, 1990. The
temperature, velocity and surface meteorological data were collected by both the ocean weather
buoy at OWS-T and the three surface buoy systems surrounding OWS-T. The best agreements
between the simulated and observed mixed-layer depths and temperatures occurred when
Richardson number Rv= 0.65 - 0.70. The simulation suggests that the horizontal advection pro
cess was as important as the vertical one-dimensional process in the variation of the mixed-layer
thickness, while it was less important than the vertical one-dimensional process in the variation of
the mixed-layer temperature in the area during the week surrounding the passage of Typhoon
#9019.
