SPECTRAL REPRESENTATION IN SABANG AND JEPARA COAST

Abstract

India ocean in optimation theoretical wave spectrum only wide spectrum and peak frequency equalized but peak energi not yet equalized hence in this research will equalize wide spectrum, peak frequency and peak energi for indonesia ocean that is Sabang coast and Jepara coast. About 12 mounth measured wave spectra from the Sabang Coast and 2 month from the Jepara Coast, were analyzed so as to determine the frequency of occurrence of peaked spectra in sea states of different intensity. This type of spectrum did not occur so often close to coast and in high sea states. A fourparameter

theoretical formulation was proposed to represent peaked spectra and was shown to provide an excellent fit to measured spectra. The average values of the spectral parameters describing the two peaks did not show any clear dependence on significant wave height. The mathematical spectrum models are generally based on one or more parameters, e.g., significant wave height, wave period, shape factors, etc. The most common single-parameter spectrum is the Pierson-Moskowitz model based on the significant wave height or wind speed. There are several two-parameter spectra available. Some of these which are commonly used are Bretschneider, ISSC and ITTC. JONSWAP spectrum is a five-parameter spectrum, but usually three or the parameters are held constant. Qualitative as well as quantitative comparisons of the optimation-yielded spectra with target spectra indicated that the developed optimation could model the wave spectral shapes in a better way than commonly used theoretical spectra.