Rotational and divergent response of baroclinic and barotropic modes to tropical heating /
A two layer inviscid incompressible channel model, icrofilm Inc. expressed as two is used to examine the flow evolutions modes (barotropic, first baroclinic), forced by transient local baroclinic convective heating, within the equatorial region. Four classes of analytically balanced background flows...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733059441&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A two layer inviscid incompressible channel model, icrofilm Inc. expressed as two is used to examine the flow evolutions modes (barotropic, first baroclinic), forced by transient local baroclinic convective heating, within the equatorial region. Four classes of analytically balanced background flows including constant zonal wind, vertical shear, lateral shear, and zero absolute vorticity are examined. Domain- averaged root-mean-square stream function and velocity potential are calculated to estimate the effectiveness of forcing the rotational and divergent parts of the barotropic and baroclinic modes. When upper and lower layer large scale zonal winds are in the same direction significant barotropic responses are observed in l4-day simulations. Constant zonal wind basic states, with upper and lower layer easterlies of 1 5 and 5 m [s'l], respectively, cause the strongest response in the barotropic stream function and velocity potential, for a given equatorial forcing. The structure of the waves differs from the quiescent state response. Strength of barotropic responses is moderately related to vertical shear. One other large response, as strong as the constant easterly zonal flow basic state run, is observed in the lateral shear case. It has weak upper (lower) layer equatorial westerlies (easterlies),midlatitude easterlies (westerlies), and critical latitudes at [30ON] and [3OOS]. The structure of the response is changed qualitatively, where the Rossby wave is trapped near the equator as in the constant easterly run, amplifying its barotropic response intensely. Barotropic response is not excited with forcing placed within a zero absolute vorticity field. Barotropic responses persist at least ten days after heating is turned off implying that tropical convection can affect the global atmosphere long after it has dissipated. Basic states with strongest response resemble mean tropical circulation in connectively active regions. |
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| Item Description: | Vita. "Major Subject: Meteorology". |
| Physical Description: | xix, 286 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 239-241). |