Modified probability density functions of tidal elevation data

Abstract

The frequency information of tidal elevation in the coastal zone is very important in the coastal development. Double-peak (bi-modal) normal distribution function having four parameters was suggested as the probability density function (pdf) of tidal elevation data in Korean coastal zone. However, it has no limit of the tidal elevation and shows a little bit poor-fit in the low-frequency region. In this study, the modified pdf is suggested to improve the poor-fit pattern in the tail areas of the existing pdf based on the weighting-method. This method is the inverse frequency method having different weighting factors with respect to the data frequency. The higher the frequency of tidal elevation data, the lower the weighting factor. This new method is tested by using hourly tidal elevation data and checked the goodness-of-fit level of the tail areas of pdf. It is clearly improved of that region, whereas slightly diminished in the other frequency areas.