Isentropic diagnostics of mid-latitude circulation and transport

This thesis examines the mid-latitude circulation and tracer transport using zonal average isentropic diagnostics. The Underworld (i.e. the region roughly below the 300K-isentrope) is targeted by our research. Currently, there is a lack of rigorous and consistent theoretical formalism to deal with isentropes that intersect the Earth's surface. In this thesis, we develop such a formalism and use it to address three main questions: (1) How is the mean circulation forced by the eddies in the region - dubbed "surface zone" - where isentropes intersect the surface in the longitude-height plane? (2) What are the pathways of global chemical transport due to mean circulation and eddies? (3) How are eddy chemical and PV transports related? A primitive-equation model on a sphere, equipped with simple physical parametrizations and on-line tracer transport, is used to investigate these questions. We tackle question (1) by looking for explanations in terms of angular momentum balance and surface heat transport. Our results show that equatorward PV flux forces a poleward mean flow in the warmer region of the surface zone. In the colder region, an equatorward mean flow is forced by eastward surface form drag, which is attributed to poleward eddy heat, flux at the surface.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Koh, Tieh-Yong, 1972-

Advisor dc:contributor.advisor

• R. Alan Plumb.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/59649

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/59649