APL Guest Seminar by Prof. Lakshmi Kantha (May 26, 2017)

Author: 2017-05-24

Announcement

Date & Time:
26 May, Friday, 15:00-16:00
Place:
Meeting Room 1+2, 2nd floor, Conference Building, Yokohama Institute
Speaker:
Prof. Lakshmi Kantha (University of Colorado at Boulder, USA)
Title:
Turbulent Mixing in the Oceans and the Atmosphere – Similarities and Differences
Abstract:
During my professional career, I have had the privilege of studying turbulence and mixing in both the oceans and the atmosphere. This has provided a unique insight into turbulent processes, specifically the similarities and differences between the two media. Unlike the atmosphere, except for a thin upper layer, oceans are opaque to electromagnetic signals and hence it is difficult to visualize turbulent processes in the interior. Only low frequency acoustic waves can be used to probe the interior of the global oceans. On the other hand, radars, sodars and lidars can all be used in the atmosphere. Special radars, such as the MU radar at Shigaraki, Japan, can be used to infer turbulence in the troposphere. During our ShUREX (Shigaraki UAV-Radar Experiment) campaigns in 2015 and 2016, we also discovered that it is possible to visualize layered and turbulent structures in the moist troposphere in unprecedented detail, when the radar is operated in range-imaging mode. The MU radar enabled us to probe interesting turbulent structures in real time using UAVs equipped with turbulence sensors and guided by high resolution radar echoes. I will present some of our findings that highlight some remarkable similarity to oceanic structures.

I will also present some preliminary results from my attempts to update the widely popular Kantha and Clayson (2004) second moment closure model of the upper oceanic mixed layer. This involves incorporating the Craik-Leibovich vortex force terms in second moment equations and doing a better job of modeling free convection. I will also discuss the difficulties involved in dealing with conventional and double-diffusive mixing that can occur together in some regions of the global oceans.

Seminar lists of the Application Laboratory is here.