Features of locally and remotely generated surface gravity waves in the inner‐shelf region of northwestern Bay of Bengal

Abstract

In this article, we studied the characteristics of locally and remotely generated wind waves in the inner‐shelf region of northwestern Bay of Bengal (BoB) based on the measured wave data. Two well‐differentiated wave systems, one young sea from the east‐southeast and another more developed swell from the south lead to bimodality in the wave spectrum. Wind‐sea predominance is not observed in the monthly average wave spectrum and in all the months swells dominated indicating a swell‐driven wave regime. During the monsoon (JJAS), the wave climate is dominated by long‐period swell from the south‐southeast and the short fetch during the northeast monsoon (ONDJ) leads to weaker easterly swells, while the effects of the sea/land breeze influence on the wave generation are more relevant during this season. During November–April, diurnal variation of 0.15 m in significant wave height (SWH) is observed. The study based on seasonally averaged ERA‐Interim reanalysis data reveals a weak connection between the waves in the northwestern BoB and the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) events. The waves are influenced by ENSO events during June–September and by IOD events during October–January, which consequently caused inter‐annual variations in monthly average SWH. The present study, however, did not show a significant inter‐annual variability in annual mean SWH during 1979–2015.

Climatology and trends of the Indian Ocean surface waves based on 39‐year long ERA5 reanalysis data

“…It is now understood that the swells generated in the SO during intense SO extra‐tropical cyclones propagate throughout the World's oceans (Hemer et al ., ). The general wave characteristics of the coastal waters of NIO are available in the literature (Sanil Kumar et al ., ; Anjali Nair and Sanil Kumar, ; Glejin et al ., ; Patra et al ., ; Anjali Nair and Sanil Kumar, ; Anjali Nair et al ., ).…”

Nearshore Waves and Littoral Drift Along a Micro-Tidal Wave-Dominated Coast Having Comparable Wind-Sea and Swell Energy

“…A 5%, 10%, 15% and 20% increases in the H s value results in 10%, 21%, 32% and 44% increases in the annual LST. Even though the waves are influenced by the sea breeze during the pre-monsoon period, the influence of sea breeze on LST is negligible (figure not shown) since the LST depends on both the wave height and wave period and these two parameters have an inverse relationship during the sea breeze period [49,53]. As discussed in Section 4.1, wind-seas and swells along the study region are comparable during non-monsoonal months.…”