[Eoas-seminar] COAPS Short Seminar Series

[eoas-seminar at lists.fsu.edu]

COAPS Short Seminar Series
11:00 AM Feb. 3rd
Attend F2F (in 255 Research A) or Virtually (via Zoom)
https://fsu.zoom.us/j/92268262553

Meeting ID: 922 6826 2553
Talks are normally 12 minutes long with an additional 8 minutes for questions.

A Multi-observation Analysis of Salinity Diffusion into the Mixed Layer in the Bay of Bengal
By Sthitapragya Ray
Description: Multi-observation 3-dimensional datasets (ARMOR3D and GLOBCURRENT) were used to compute the mixed layer salinity budget over the Bay of Bengal (BoB) and the residual of the budget was used to compute the eddy diffusivity of salinity at the base of the mixed layer. The estimated diffusivity values were subsequently used to compute the contribution of vertical diffusion of salinity (VDIFF) to the salinity tendency (ST) in the mixed layer. Diffusivity values of the order of 10^(−4) 𝑚^2∕𝑠 were observed over most of the basin, and the resulting VDIFF was identified as a leading order contributor to the salinity budget, with mean horizontal advection (MHADV) being the only other comparable contributor. The salinity variability within the BoB was observed to be dominated by the fresh water influx during summer monsoon and post-monsoon seasons and the subsequent advection of these waters along the western margin of the Bay by the East India Coastal Current (EICC). VDIFF counteracted the freshening effect of the MHADV of this freshwater, and the long-term (seasonal) variability of VDIFF was coherent with the vertical gradient of salinity, while its short-term (intraseasonal) variability was coherent with diffusivity variations. Diffusivity was observed to be primarily determined by the static stability (measured in terms of the squared Brunt-Väisälä frequency at mixed layer depth). Although surface windstress and buoyancy flux (which generate turbulent kinetic energy) also played an important role in determining diffusivity, as illustrated by a multiple linear regression model.

On the dynamics of the subtropical mode water from an ensemble view
By Luolin  Sun
Description:  The subtropical mode water (STMW) experiences a seasonal cycle of formation and erosion, and it has significant impact on the atmosphere-ocean interactions and the structure of the upper ocean. We here discuss such mechanisms from a dynamical perspective. We employ an ensemble of 48 North Atlantic Ocean simulations at mesoscale permitting resolution (1/12 degree) and characterize the STMW by a pool of low Ertel potential vorticity (PV) obtained for the ensemble-mean flow. This ensemble-based approach offers us the advantage of investigating the temporal variability of the STMW which is quantified by the annual evolution of the PV pool. Our finding reveals that the seasonal cycle of the STMW is mainly governed by the ensemble-mean flow and the eddies play an secondary role in the PV dynamics.

NOTE: Please feel free to forward/share this invitation with other groups/disciplines that might be interested in this talk/topic. All are welcome to attend.

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