Observed wave characteristics during growth and decay: a case study

Observed 1-h time series data on sea surface waves in the shelf waters off Goa, west coast of India (depth 80 m), during 17–24 March 1986, are analyzed with reference to the prevailing synoptic winds to understand wave growth and decay aspects. Wind speeds (U10) ranged from 0 to 11.5 m s−1, whereas significant wave height (Hs) varied between 0.6 and 2.3 m. Cross-correlation analysis betweenU10 andHs revealed a time-lag of 4 h. A relationship is obtained between wave steepness (Hs/L) and wave age (C/U10) viz. Log10(Hs/L= -0.53 Log10(C/U10) − 1.385. Phillipsʹ hypothesis off−5 formula for equilibrium range of wave spectrum and relationship between non-dimensional energy (E* = Eg2/U*4) and non-dimensional peak frequency (v* = U*fm/g) are studied. Correlation of non-dimensional wave parameters (E* andv*) using the present data showed a better aereement with Hasselmannet al. (1976) when comnared to Toba (1978).