A boundary-layer wind profiler has been operated continuously in downtown Montreal as a collaborative project of McGill University and the NOAA Aeronomy Laboratory. The records contain hundreds of hours of data on the melting layer of snow, consisting of Doppler spectra in the vertical profiler beam with a typical height resolution of 100 m and a time resolution of about 1 minute. A particular case study day was selected for analysis of precipitation processes associated with the melting of snow to become rain. We have examined the Doppler spectra just above and below the melting layer for evidence of aggregation or breakup during melting. Apart from the complete spectrum, we also show that the product of the mean Doppler velocity and the reflectivity factor in snow should be equal to that in the rain if aggregation and breakup are negligible. Both approaches indicate that there are times when snow merely melts to become rain, each snowflake forming one drop, but other times when aggregation or breakup are evidently important. It appears breakup is associated with regions of higher reflectivity.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.55490 |
| Date | January 1994 |
| Creators | Drummond, Fiona Jean |
| Contributors | Rogers, R. R. (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: 001430384, proquestno: AAIMM00016, Theses scanned by UMI/ProQuest. |
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