Surface tension drives waves shorter in wavelength than a few centimeters. So the big waves we see on the ocean are gravity waves. Waves in the ocean are powered by wind. The wind first builds surface tension waves. It then pushes on the surface tension waves giving them energy, increasing their amplitude and waqvelength until they become gravity waves.
Winds can deform waves from a simple sinusoid.
Wind the wind makes the waves too high compared to their wavelength the waves will break. Several waves can arrive at the same time from different directions with different wavelengths. These waves add together to create a complex pattern. In deep water, when the wave height exceeds seven times the wavelength, the wave breaks. Math Root Average period To find the average period of the wave add together the periods and divide by the number of measurements.