Parameter identification of JONSWAP spectrum acquired by airborne LIDAR
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In this study, we developed the first linear Joint North Sea Wave Project (JONSWAP) spectrum (JS), which involves a transformation from the JS solution to the natural logarithmic scale. This transformation is convenient for defining the least squares function in terms of the scale and shape parameters. We identified these two wind-dependent parameters to better understand the wind effect on surface waves. Due to its efficiency and high-resolution, we employed the airborne Light Detection and Ranging (LIDAR) system for our measurements. Due to the lack of actual data, we simulated ocean waves in the MATLAB environment, which can be easily translated into industrial programming language. We utilized the Longuet-Higgin (LH) random-phase method to generate the time series of wave records and used the fast Fourier transform (FFT) technique to compute the power spectra density. After validating these procedures, we identified the JS parameters by minimizing the mean-square error of the target spectrum to that of the estimated spectrum obtained by FFT. We determined that the estimation error is relative to the amount of available wave record data. Finally, we found the inverse computation of wind factors (wind speed and wind fetch length) to be robust and sufficiently precise for wave forecasting.
Key wordsJONSWAP spectrum parameter identification least square method airborne LIDAR
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This work is supported by the Scientific Instruments Development Program of NSFC (No. 615278010), and the National Key Basic Research Program of China (973 program) under grant No. 2014CB845301/2/3.
- Dean, R. G., and Dalrymple, R. A., 1984. Water Wave Mechanics for Engineers and Scientists. Prentice-Hall Inc., Upper Saddle River, NJ, USA, 72pp.Google Scholar
- Hasselmann, K., 1973. Measurement of wind wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP). Deutsche Hydrographische Zeitschrift, A (8): 95.Google Scholar
- Naderi, M., and Patzold, M., 2015. Design and analysis of a one-dimensional sea surface simulator using the sum-of-sinusoids principle. In: OCEANS 2015–MTS/IEEE Washington. Washington DC, 19–22.Google Scholar
- Synder, R. L., 1974. A field study of wave induced pressure fluctuation above surface gravity waves. Journal of Marine Research, 32: 491–531.Google Scholar