Publication Date

Spring 2013

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Climate Science

Advisor

Alison F. Bridger

Keywords

atmosphere, dust, dynamics, Mars, modeling, storm

Subject Areas

Atmospheric sciences; Planetology; Meteorology

Abstract

A survey of observations and analyses of the Mars year (MY) 25 planet-encircling dust storm (PDS) on Mars is presented. The environmental causes and dynamical mechanisms responsible for PDS initiation, expansion, decay, and interannual frequency are not fully understood. PDS seasonal occurrence suggests the presence of climatic and environmental components, yet interannual variability suggests that initiation and expansion mechanisms are not solely seasonal in character. The objectives of this research were to better understand the dynamical processes and circulation components responsible for MY 25 PDS initiation and evolution and to analyze why a PDS developed in MY 25 and not in MY 24 or 26.

Negative anomalies in temperature data with &sim3-sol periodicity indicate the presence of baroclinic eddies. After comparing these eddies with dust storms observed in satellite imagery, the author hypothesized that six eastward-traveling transient baroclinic eddies triggered the MY 25 precursor storms due to the enhanced dust lifting associated with their low-level wind and stress fields. They were followed by a seventh eddy that contributed to dust storm expansion. All seven eddy cold anomalies were less than -4.5 K. It is possible that the sustained series of high-amplitude eddies in MY 25 were a factor in PDS onset and expansion.

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