NUMERICAL SIMULATION OF TYPHOON SURGES ALONG THE EAST COAST OF ZHEJIANG AND JIANGSU PROVINCES

Using conventional two-dimensional nonlinear storm model, the storm surges caused by the six ty-phoons with different kinds of tracks which hit the coast of Zhejiang and Jiangsu Provinces including Shanghai during the period from 1953 to 1974 are computed numerically. To avoid the nonlinear and linear computational instabilities, a finite-difference scheme with the quadratic conservation (or the semi-momentum) is adopted and a criterion for linear computational stability is derived. The basic parameters used in this computation are: the space step Δs=30km, the time step Δt=200sec, the coefficient of the wind stress = 2.6 "10-> and the coefficient of the bottom friction v&2=2.0x 10-'. The pressure and surface wind distribution for typhoon are assumed to be characterized by Fujita's pressure formula and Uerto's wind model, respectively.