Practically Rapid Determination Of Typhoon Wave Field For Safe Navigation

Currently, taking the Chinese major ocean shipping companies for instance, when the deck officers and company marine security officers formulate typhoon-avoiding plans,they majorly refer three elements:the range of fresh gale and storm released by Japanese JMH, the barometric pressure near the center of typhoon,the distance from ship to typhoon, generally don’t consider wave field,but the destructi-veness and importance of typhoon wave field also can’t be ignored.Therefore, in order to supplement and improve typhoon-avoiding plan,assist ships more safely and economically to avoid typhoon, this article proposes the practically rapid determination of typhoon wave field for safe navigation.This article widthwise contrasts the wave forecast accuracy(wave field of 3m and 4m) of the past six typhoons between NMEFC and JMA,analyzes the relationship between typhoon wave field and wind field,proposes the rapid determination of typhoon wave field based on Envelope theory,namely the Chinese-Japanese synthesized envelo-pe wave field.Under conditions of ignoring the wind field,barometric pressure,distance, only considering the wave field factor,two typhoon-avoiding simulations to the wave field have been done using the method during the event of NO.1415 Typhoon Kalmaegi.The main results are as follows:(1)In terms of the wave forecast for the six typhoons,from the perspective of overall average forecast accuracy,the Japanese forecast is more accurate,from the perspective of single forecast accuracy,sometimes the Chinese forecast is more accurate.But the past forecast accuracy is high or low,which can’t stand for the future forecast level,therefore,we suggest ships synthetically refer the Chinese and Japanese wave forecast.(2)The forecast for wave field and wind field of the same typhoon on the same day.regardless China or Japan, whose single wind circle and synthesized wind circle intersect with the synthesized wave circle.there is a large part of the wave field area which isn’t covered by the wind field.This shows that ships only consider the wind field to avoid typhoon isn’t enough and incomplete,the wave field also should be considered. (3)In example 1, ship A only refers Chinese wave forecast, ended in failure.While we redesign the route refering the Chinese-Japanese synthesized wave field, it turns out successfully typhoon-avoiding.In example 2, ship B only refers Japanese wave forecast, ended in failure.While we redesign the route refering the Chinese-Japanese synthesized wave field, it turns out successfully typhoon-avoiding.The positive and counter examples in the two simulations have brightly effectively proved that the papid determination of typhoon wave field proposed by this article has some practicability and feasibility.If adding it to the "three elements" typhoon-avoiding plan as a supplement,which will help ships more safely and economically avoid typhoon.