The influence of boundary layer pumping on an externally-forced
synoptic-scale flow is examined. The results follow earlier theories of
stratified incompressible Boussinesq flow. These theories state that
the spin-down time scale and the penetration depth of the influence of
boundary layer pumping are inversely proportional to the stratification
and directly proportional to the horizontal length scale of the flow.
However, the present development is performed in isentropic coordinates
which allow estimates applicable to the atmosphere, and implicitly includes
nonlinear influences due to tilting and vertical advection. This
analysis indicates that boundary layer pumping could be important synoptically
in the lower troposphere under conditions of significant surface
stress and tropospheric stratification.
The influence of stratification and accelerations on synoptic-scale,
boundary layer production of vertical motion is examined for the
case of oscillating boundary-layer flow driven by time-dependent, horizontally-
periodic surface temperature perturbations. It is found that
only very strong stratification can significantly reduce the boundary
layer pumping through pressure adjustments within the boundary layer.
As a step in understanding the complicated dynamics of the structure of
accelerated stratified boundary layers, order-of-magnitude analyses of
variables for each layer are examined. This structure depends on the
relative magnitude of the non-dimensional forcing frequency and the product
of the stratification parameter and Ekman number. Applications to
both synoptic and diurnal atmospheric circulations are considered. / Graduation date: 1978
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28910 |
| Date | 29 March 1978 |
| Creators | Park, Soon-Ung |
| Contributors | Mahrt, Larry J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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