V. Thushara

Pusan National University | PNU · IBS Center for Climate Physics

Seasonal variability of the vertical structure of chlorophyll-a (chl-a) in the central Arabian Sea is described using seasonal climatology from bio-Argo floats. A quarter-degree resolution coupled OGCM-ecosystem model is employed to explain the physical and biogeochemical processes that determine the observed seasonality of the chl-a profiles. The...

Plain Language Summary Biological productivity in the ocean is affected by large‐scale climatic events, such as the Indian Ocean Dipole (IOD), through its control on the upper‐ocean dynamics. In 2016, the Indian Ocean witnessed an extreme negative IOD, characterized by strong anomalies in surface temperature and winds. During this period, unusually...

Signatures of Rossby waves that are evident in satellite ocean colour data in the southeastern Arabian Sea (SEAS) are more prominent during the winter than the summer monsoon. During the winter, the sea level is high, and the conditions are less conducive for the injection of nutrients through the eddy-pumping mechanism. In this study, we use satel...

The northern Bay of Bengal receives a large amount of fresh water through river runoff and rainfall during the Indian summer monsoon (June–September). This fresh water spreads offshore and can modulate the upper-ocean chlorophyll via two processes: advection of river nutrients and inhibition of vertical supply of subsurface nutrients by increasing...

The Bay of Bengal (BoB) generally exhibits surface oligotrophy due to nutrient limitation induced by strong salinity stratification. Nevertheless, there are hotspots of high chlorophyll in the BoB where the monsoonal forcings are strong enough to break the stratification; one such region is the southern BoB, east of Sri Lanka. A recent field progra...

Measurements of surface heat and moisture fluxes, wind stress and upper atmospheric observations have been made to examine air-sea interaction and boundary layer processes in the southern Bay of Bengal (BoB) in the Bay of Bengal Boundary Layer Experiment (BoBBLE) with ship-borne instrumentation. During the studies, micrometeorological and oceanogra...

During the Bay of Bengal (BoB) Boundary Layer Experiment (BoBBLE) in the southern BoB, time series of microstructure measurements were obtained at 8◦ N, 89◦ E from 4–14 July, 2016. These observations captured events of barrier layer (BL) erosion and re-formation. Initially, a three-layer structure was observed: a fresh surface mixed layer (ML) of t...

The Bay of Bengal (BoB) generally exhibits surface oligotrophy, due to nutrient limitation induced by strong salinity stratification. Nevertheless, there are hot spots of biological activity in the BoB where the monsoonal forcings are strong enough to break the stratification; one such region being the southern BoB, east of Sri Lanka. A recent fiel...

The Bay of Bengal (BoB) plays a fundamental role in controlling the weather systems that make up the South Asian summer monsoon system. In particular, the southern BoB has cooler sea surface temperatures (SST) that influence ocean–atmosphere interaction and impact the monsoon. Compared to the southeastern BoB, the southwestern BoB is cooler, more s...

The Bay of Bengal (BoB) is considered to be a region of low biological productivity, owing to nutrient limitation, caused by strong salinity stratification induced by the freshwater influx from rivers and precipitation. Satellite and in situ observations, however, reveal the presence of prominent regional blooms in the bay in response to monsoonal...

The intense winter phytoplankton bloom during November – February in the northeastern Arabian Sea (NEAS) was thought, until recently, to be controlled only by a convective deepening of the mixed layer (ML) owing to cool and dry northeasterlies. But, a recent study has shown that the deepening of the ML in the southern NEAS is inhibited by the polew...

The diurnal cycle is an important mode of sea surface temperature (SST) variability in tropical oceans, influencing air-sea interaction and climate variability. Upper ocean mixing mechanisms are significant at diurnal timescales controlling the intraseasonal variability (ISV) of SST. Sensitivity experiments using an Ocean General Circulation Model...