تعيين پارامترهاي تابع توزيع پواسن -گامبل جهت تخمين ارتفاع موج اكستريم درياي خزر جنوبي

The objective of this study is the determination of distribution function parameters of Poisson - Gumbel in order to estimate extreme wave height in Southern Caspian sea and recognization of sea Caspian wave climate. This study is done with 20012 wave data that are recorded by the bouy in loacted at latitude 37°, 6ʹ N and longitude 53°, 18ʹ E and at a distance 28 Kilometers from Neka of shore within 1988-1992. Because of limitation of temporal length of oceanic data, wave height data on Neka bouy are sampled by peak over threshold method with selected Threshold value equals 2.30 m. The result sample consist of 10 extreme wave height data of over threshold. Then, in order to determination of parameters of Poisson - Gumbel distribution function, the selected extreme wave height data of over threshold are fitted Poisson-Gumbel distribution function by moment method. By comparing extreme wave data of over threshold of Neka bouy with estiminated extreme wave height in the Caspian sea accruing on Poisson - Gumbel distribution function, it is found that the relative error of calculations equals 35% . Probably, the most percent of this error is due to: - missing wave data in 2 years duration through battery discharge of Neka bouy . - Because of lack of adequate-measurement on oceanic waves, deportation 15% of significant heigt annual mean in single year than long period average value.