A variational semi-Lagrangian wind retrieval algorithm from single-Doppler radar data is studied both analytically and numerically, in order to understand its responses as well as limitations. The theoretical background on which the algorithm is based, is described in detail. A new approximation of the conservation equation of reflectivity for wind retrieval purposes is derived. It is shown that, in general, a unique wind field may not be available for the entire domain. However, some ways of minimizing this inconvenience are presented. The existence of a spurious solution when the conservation equation of a tracer is discretized is found analytically. A real case (a storm characterized by a mesocyclonic circulation) is used in order to illustrate the problem of the non-uniqueness of the solution. This is carried out through the study of the sensitivity of the algorithm to the moving frame and the initial guess. In addition, the influence of each one of the constraints used (conservation of reflectivity, continuity equation, smoothness constraint) in the retrieved wind field are analyzed. It is concluded that in spite of the sources of error described, the results may be meaningful.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.27515 |
| Date | January 1997 |
| Creators | De Elía, Ramón. |
| Contributors | Zawadzki, Isztar (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Atmospheric and Oceanic Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001616029, proquestno: MQ37113, Theses scanned by UMI/ProQuest. |
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