Course Details
Subject {L-T-P / C} : ER6015 : Physical and dynamical Oceanography { 3-0-0 / 3}
Subject Nature : Theory
Coordinator : Prof. Naresh Krishna Vissa
Syllabus
Ocean sciences and the scope of physical oceanography: World Ocean, origin, history of oceanography, challenges. Seawater and its properties: Temperature: definition, measurements, distribution, Salinity, pressure, depth, density. Pressure effects on temperature and density. TS Diagrams, water types, and water masses. Sound in the sea, Light in the sea, Colour of seawater. Temperature, Salinity and density distributions. Transparency of seawater. Heat budget of the oceans: Heat budget terms, Short and Long wave radiation, Evaporation, Heat conduction. Ocean Waves and Tides.
The equation of motion in oceanography: The non-linear terms in the equation of motion, scaling and the Reynolds Number, Reynolds stresses, equations for the mean or average flow, Reynolds stresses and eddy viscosity, scaling the equations of motion Rossby number, Ekman number, effects of rotation. Currents without friction geostrophic flow. Currents with friction winddriven circulation: Nansen's qualitative argument, the equation of motion with friction included, Ekman's solution to the equation of motion with friction present. Ekman transport, upwelling and downwelling away from boundaries. Sverdrup's solution for the wind-driven circulation, application of the Sverdrup equations, the mass transport stream function. Westward intensification—Stommel's contribution, the planetary wind field and the drag coefficient CD,Munk's solution, comments on Munk's solution. Vorticity: relative, planetary, absolute and potential. Westward intensification of ocean currents explained using conservation of vorticity. Oceanic mesoscale eddies, formation of sub-tropical gyres, equatorial current systems, monsoonal winds and currents over the North Indian Ocean Somali current Southern Ocean - Swells.
Course Objectives
- The course will provide a broad background of the concepts of Physical Oceanography, including topics such as observation instruments, seawater properties, basic theories of ocean dynamics, and major ocean currents.
- This course is an introduction to dynamics of Ocean as it relates to oceanic flows. The focus of the course is understanding the basic concepts in fluid dynamics, such as dynamical components of the equations of motion, Lagrangian vs. Eulerian motion, vorticity dynamics, Ekman dynamics, rotating waves, basin scale circulation and quasi-geostrophic dynamics, the effects of stratification and the use of layer models, instability theory, hydraulic control, and turbulent mixing.
Course Outcomes
The class will provide a basic understanding of how the ocean works and how physical and modelling scientists conduct their studies.
Essential Reading
- Talley L. D., G. L. Pickard, W. J. Emery and J. H. Swift, Descriptive Physical Oceanography, Elsevier Academic Press
- Pond S. and G. L. Pickard, Introductory dynamical oceanography, Butterworth-Heinemann
Supplementary Reading
- Neumann G, Ocean currents, Elsevier Publishing Company
- Reddy M, Descriptive Physical Oceanography, Oxford and IBH Publishing Company