A RPN spectral model (Recherche en Prevision Numerique, Canada) is modified to study the effects of rotation on the general circulation of an idealized earth's atmosphere. The present model is comprised of the same description of dynamic processes as set up in the RPN model and simplified physics such as the Newtonian heating function and the vertical dissipation of momentum with constant kinematic viscosity. Except for the equilibrium temperature profile being assumed to be a function of height and latitude, all other physical parameters are taken to be constant in time and space. A 15 mode triangular truncation, 5 sigma levels, and either a 20 minute or 40 minute time increment are adopted for the model resolution. Either 100 or 200 earth rotations of time integrations are performed starting from a state of rest. Statistically steady states obtained from six experiments (for 0.3, 0.8, 1.0, 1.2, 1.5, and 2.0 times the earth rotation rate, respectively) are taken to study the system's response to different rotation rates. / The results from the model for the earth rotation case reveal several features seen in the real atmosphere. Some quantitative discrepancies include a stronger jet stream velocity, a steeper north-south temperature gradient, and a weaker but wider Hadley cell. Most of the discrepancies are due to the use of a constant relaxation coefficient which overestimates the diabatic heating in the mid-latitudes but underestimates it in the tropics. When the rotation rate is decreased, the intensities of the Hadley cell and the jet stream are increased, the intensity of the eddy processes is decreased, and the centers of the zonally symmetric fields shift to the higher latitudes. As the rotation rate is increased, smaller scale motions dominate the circulation, the intensities of the Hadley cell, the jet stream, and the eddy processes are decreased, and the location of the maxima of the zonally symmetric fields move to lower latitudes. The trend in which the characteristic scale of motion change with rotation rate agrees with the linear theory of baroclinic instability. The fundamental results of the model are that the strongest Ferrel cell and strongest eddy processes are found in the earth rotation case. These results are consistent with a weakly nonlinear theory of baroclinic waves and with observational results from rotating annulus experiments. / Source: Dissertation Abstracts International, Volume: 42-10, Section: B, page: 4095. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74679 |
| Contributors | LU, HUEI-IIN., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 166 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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