Abstract
Wave hindcastings in the Japan Sea by the third generation model SWAN under input MSM winds conditions were conducted for April 3-4, 2012 Low Pressure System (LPS) and the virtually-modulated LPSs concerning strength, course and moving speed. Investigations of the largest maximum significant wave height HmaxM generated by each LPS show the following results: 1) the effect of time increment Δt used in wave hindcasting on HmaxM is significant and consequently use of Δt yielding the Courant number less than 1.5 for the lowest frequency and space increment is recommended, 2) a 15 % increase of wind speed in the Japan Sea yields HmaxM close to that based on 100, 000-year simulations, 3) the actual LPS took a course generating the largest HmaxM among the supposed LPSs, 4) 2/3 decrease in translation speed of the LPS gives the largest 1.1 m increase in HmaxM. A final conclusion is that the concerned LPS may have brought about extraordinarily high wave heights to the northeastern coastal area of the Japan Sea under actually-conceivable quasi-worst LPS conditions.
