It is argued that for many regions of the earth, ground based remote sensing techniques for rainfall measurement are impractical due to their cost and limited range of coverage. Global rainfall estimates must therefore be provided largely by satellites, particularly those exploiting atmospheric windows in the visible/IR and microwave regimes. / A 2-D pattern matching technique using visible and IR data is proposed and its accuracy investigated. Because these wavelengths respond primarily to cloud and not rain sized drops, significant accuracy may be achieved in rain areas, but not directly in amounts. However, when long term average rain rates for raining areas are used, errors of (TURN) (+OR-) 49% for 10('5) km('2) are achieved. This compares favorably with other techniques based on cloud life histories. / Microwave radiometer-based techniques are also investigated and are found to be fundamentally limited in accuracy ((TURN) (+OR-) 70%) by the large variations in the (unknown) effective rain layer height. However, useful accuracy ((TURN) (+OR-) 20%) may be obtained over large areas ((TURN) 10('5) km('2)), provided that the long term average effective rain layer height is known. It is argued that a once or twice daily satellite rain estimate is insufficient for either accurate estimates of daily accumulation or for samples of climatological rain rates. A hybrid microwave satellite-vis/IR technique is therefore proposed in order to solve the temporal resolution problem without the necessity of orbiting many microwave radiometers. This technique would take advantage of the high ( 1/2 hour) temporal resolution of the vis/IR data and could achieve accuracies of (TURN) (+OR-) 20% for 12 hour accumulations over 10('5) km('2) provided that the mean effective rain layer height is known. The practical implementation of such a technique will ultimately depend on the relative difficulty of measuring the mean effective rain layer height, and the mean rain rate for raining areas as well as the availability of appropriate sensor platforms.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.68614 |
| Date | January 1981 |
| Creators | Lovejoy, S. (Shaun), 1956- |
| 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 | Doctor of Philosophy (Department of Physics) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000139955, proquestno: AAINK54847, Theses scanned by UMI/ProQuest. |
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