“…In Bay of Bengal & Andaman sea, using in situ measurements, IW of varying period of heights are studied by Hareesh Kumar et al (2002), Murthy (2000), Sarma et al (1991), Antony et al (1985), and the depth of thermocline undergoes an annual cycle (La Fond and Poornachandra Rao 1954), as well as oscillations with periods equal to tidal cycles (Hareesh Kumar et al 2008), and shorter period are also prominent because they occur between the shallow, low-density surface layer, and the denser water below. Vertical oscillations or internal waves by convergence and divergence appear as long bands of alternately smooth and rough water on the surface (La Fond 1961).…”