Eddy activity and its role in barrier layer thickness variability in the southeast Indian Ocean

Ocean stratification can modulate the upper ocean response and its feedback to atmospheric forcing. Surface freshwater input by advection and precipitation, for example, can change the upper ocean stratification and produce barrier layers. The existence of a barrier layers can affect SST in several ways, for example by reducing entrainment of cooler water at the base of the mixed layer, and consequently may impact air--sea interactions. In the southeastern Indian Ocean, eddies are abundant and can act on transporting warm and fresh waters westward, thus possibly contributing to the formation of barrier layers. Here we initially evaluate the importance of eddy activity in contributing to barrier layer formation and intraseasonal variability in the southern Indian Ocean. Using 15 years (2005-2019) of ocean reanalysis daily data, we estimate how much of the spatial and time variability of barrier layer thickness is related to eddy activity, which is determined by calculating eddy kinectic energy. With the establishment of a relationship between eddy activity and barrier layer thickness, we then proceed to estimate the relationship between barrier layer thickness and local SST anomalies. This way, we seek to infer the significance of eddy activity in affecting SST through barrier layer formation, and thus its potential impact in air--sea interactions and coupled weather systems such as the MJO.