Using rotated principal component analysis, 200mb wind data from
the First GARP Global Experiment are analyzed in the East Asia winter
monsoon region. It is found that there exist slowly eastward-moving
disturbances with a wind-speed maximum embedded in the jet stream
(jet streak). The implied vertical circulation that is transverse to
the jet streak is thermally direct in the entrance region of jet
streak and thermally indirect in the exit region.
The Lagrangian momentum equation for transient part of the flow
indicates that the magnitude of westerly acceleration of an air
parcel moving through the jet streak is related to the Coriolis
acceleration of the transient ageostrophic flow, the advection of
mean momentum by transient flow and momentum conversion between mean
and transient flow due to transient eddies. Estimates of terms in
this equation in the entrance region of jet streak suggest that the
increase of westerly momentum due to the Coriolis acceleration of the
ageostrophic flow is mostly balanced by the decrease due to the mean
easterly momentum advection by the transient jet-streak flow. Thus,
the confluence theory of Namias and Clapp (1949) appears to be valid
for the slowly moving jet streaks in the East Asia jet stream. / Graduation date: 1989
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29007 |
| Date | 24 May 1988 |
| Creators | Huang, Huei-I |
| Contributors | Esbensen, Steve |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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