Two distinct thermocline domes in the Bay of Bengal
N Anup*, V Vijith, Abhisek Chatterjee
Cochin University of Science and Technology, Kochi, India
Dept. of Physical Oceanography, Lakeside Campus, CUSAT Cochin, Kerala, India Pincode: 682016 Mobile: 9037638987 E-mail: firstname.lastname@example.org
Thermocline domes are observed over world oceans and are usually associated with the cyclonic circulation with isotherms elevated and shaped like a dome. The study investigates the occurrence and evolution of domes in the Bay of Bengal (BoB). Climatological observation shows two prominent negative anomalies in sea level in the BoB. Associated with this low sea level, a pronounced thermal dome develops in both regions, as shown by the doming of isotherms. The first dome is known as Northern BoB Dome (NBBD), located in the northwestern BoB (86-89o E and 16-19o N) from May to September which is reported for the first time. The second dome is better known as Sri Lanka Dome (SLD), located in the southern BoB (83-87o E and 5-10o N) that develops from June to September. Here in this study, we focus on the evolution of the NBBD which is then compared with the SLD. The mixed-layer heat and nutrient budget are calculated by tracking two domes to understand how the different physical processes impact these two domes. Our analysis shows that higher near-surface stratification in the NBBD inhibits the entrainment of nutrients and cooler waters to the surface compared to the SLD. This difference causes the domes to behave distinctly from the point of view of surface chlorophyll and temperature distribution.