The Penn-State/NCAR MM5 mesoscale model was adapted for mesoscale
simulations of the Martian atmosphere (the OSU MMM5). The NASA Ames Mars
GCM provides initial and boundary conditions. High-resolution maps for albedo,
thermal inertia and topography were developed from Mars Global Surveyor (MGS)
data; these baseline maps are processed to appropriate resolutions for use in the GCM
and the mesoscale model. The OSU MMM5 is validated in Chapter 2 by comparing
with surface meteorology observed at the Viking Lander 1 (VL1) and Mars
Pathfinder (MPF) landing sites. How the diurnal cycle of surface pressure (the
surface pressure tide) is affected by boundaries, domain/nest choices and the
resolution of surface properties (topography, albedo and thermal inertia) is examined.
Chapter 2 additionally shows the influence of regional slope flows in the diurnal
surface pressure cycle for certain locations on Mars. Building on the methods of
Chapter 2, Chapter 3 describes the northern midsummer polar circulation and the
circulations (both large and small scale) that influence it. Improvements to the model
for these studies include: the topographical gradient is now considered when
computing surface insolation, and the thermal inertia maps and model initialization
are improved for high latitudes; this yields a realistic simulation of surface
temperatures for the North Pole Residual Cap (NPRC) and the surrounding region.
The midsummer polar circulation is vigorous, with abundant and dynamically
important transient eddies. The preferred locations of transients varies significantly
during this study, between L[subscript s]=l20 and L[subscript s]=l50. At L[subscript s]=l20 transient circulations are
seen primarily along the NPRC margin, consistently producing strong flow over the
residual cap (~l5 m/s). By L[subscript s]=135, transient eddies form a "storm track" between the
northern slopes of Tharsis and the NPRC. By L[subscript s]=150, the circulation is becoming
strong and winter-like. These transient eddies may be important in the Martian
annual water cycle; many of the observed circulations are poorly (or not) simulated in
present day Mars GCMs. Increased resolution and polar stereographic domains
provide improvement over GCMs for high latitude studies of atmospheric
circulations. These results are in agreement with recent observations. Future work
includes model refinements and water vapor transport studies. / Graduation date: 2005
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28705 |
| Date | 01 October 2004 |
| Creators | Tyler, Daniel Jr |
| Contributors | Barnes, Jeffrey R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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