Analysis of sea wave characteristics at Qinhuangdao station

Based on the sea wave observation data of Qinhuangdao Ocean Station from March 2015 to November 2020, this paper analyzes the wave characteristics of Qinhuangdao in spring, summer and autumn. The results show that the wave type of waves in different months and years are roughly the same. There are only two types of waves, mainly wind waves (F), with a probability of more than 90%, and mixed waves-surges (U/F) appearing less frequently. The sea situation is between level 1～6, with level 2 and 3 as the main, level 4 as a supplement, level 1 second, and level 5 and 6 occasionally occur. The months when Grade 6 sea situation appear are July and August. In spring (March to May), the sea situation is mainly grade 3, and in autumn (September to November), the sea situation is mainly grade 2 to 3, showing obvious seasonality. The years when Grade 6 sea situation appeared were 2017 and 2018. The appearance of Grade 6 sea situation in these two years was affected by extratropical cyclones. There is no obvious correlation between wave height and period. The process of rough sea along the Qinhuangdao coast is mainly affected by cold air, extratropical cyclone, and the combination of cold air and extratropical cyclone. The increase of wave height in October and November is mainly related to cold air.