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Snow particle size investigations using digital image analysis - implications for ground observations and remote sensing of snow
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- Ingvander, Susanne, 1979- (author)
- Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK),Glaciology
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- Peter Jansson, Peter, Professor (thesis advisor)
- Stockholms universitet,Institutionen för naturgeografi och kvartärgeologi (INK)
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- Matti Leppäranta, Matti, Professor (opponent)
- University of Helsinki, Department of Physics
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(creator_code:org_t)
- ISBN 9789174473711
- Stockholm : Department of Physical Geography and Quaternary Geology (INK), Stockholm University, 2011
- English 38 s.
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Series: Dissertations from the Department of Physical Geography and Quaternary Geology, 1653-7211 ; 27
- Related links:
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https://urn.kb.se/re...
Abstract
Subject headings
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- During the past century climate warming has caused rapid changes in the Cryosphere. This has increased the need to accurately monitor rates of change in snow and ice in remote or sparsely populated areas where environmental observing capacity is limited. Monitoring snow cover requires understanding of the snow pack and the snow surface attributes. Snow particle size is an important parameter for characterization of snow pack properties. The size and shape of the snow particles affects the snow/air-ratio which in turn affect how energy is reflected on the snow surface. This governs the snow pack energy balance by changing the albedo or backscattering properties of the snow. Both the albedo and the snow particle size can be quantified by remote sensing. However, the snow particle size estimated by remote sensing, also called the optically equivalent particle size, represents only an approximation of the true or physical particle size of snow. Thus, there is demand for methods that relate both parameters and help to improve the interpretation of remote sensing data of snow at higher spatial and temporal scales. To address this demand the aim of this dissertation thesis is to improve existing sampling methods of the physical snow particle size to retrieve high-resolution, spatial and temporal data sets for validation of remote sensing data. A field sampling method based on object-oriented analysis of digital images was developed that allows measurements of various snow particle size parameters such as length, width, area, specific surface area and shape. The method generates a continuous snow particle size distribution that supports the detailed statistical characterization of a large number of samples. The results show its possibility to compare data from different existing methods. The sampling method was applied in field sites in Antarctica and in northern Sweden, to characterize the spatial variability in the physical snow particle size and to estimate correlations between various remote sensing products and the observed physical snow particle size. The results of the presented studies show that more detailed measurements of snow particle size in the field at higher temporal and spatial scales can improve the interpretation of active and passive satellite retrieved data.
Subject headings
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)
Keyword
- snow
- remote sensing
- particle size
- Antarctica
- in-situ sampling
- seasonal snow
- Physical Geography
- naturgeografi
Publication and Content Type
- vet (subject category)
- dok (subject category)
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