Snow monitoring using microwave radars

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Doctoral thesis (article-based)
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Date
2001-01-19
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Mcode
Degree programme
Language
en
Pages
31, [73]
Series
Report / Helsinki University of Technology, Laboratory of Space Technology, 44
Abstract
Remote sensing has proven its usefulness in various applications. For mapping, land-use classification and forest monitoring optical satellite and airborne images are used operationally. However, this is not the case with snow monitoring. Currently only ground-based in situ and weather measurements are used operationally for snow monitoring in Finland. Ground measurements are conducted once a month on special snow courses. These measurements are used to update the hydrological model that simulates the runoff. Recently optical images (NOAA AVHRR) have been tested to derive a map of the areal extent of snow. However, during the snow melt, which is the most important period for hydrology, there are few cloudless days and, therefore, the availability of optical data is limited. That is why microwave remote sensing can play an important role in snow melt monitoring due to its unique capability to provide data independent of sun light and in almost all weather conditions. The synthetic aperture radar (SAR) data may make a significant contribution to satellite observations of snow by bridging the period between the on-set and end of snow melt. Microwave radiometers can be used to retrieve the snow water equivalent of dry snow, but they cannot be used to distinguish wet snow and wet ground during the melting period. The results of the thesis indicate that, even in the presence of forest canopies, (1) wet snow can be distinguished from dry snow and bare ground, (2) snow-free areas can be identified, (3) seasonal evolution of snow cover can be monitored and (4) snow-melt maps showing the fraction of snow-free ground (wet ground) and snow (wet snow) can be derived from SAR images.
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Keywords
remote sensing, SAR, snow monitoring, microwave backscattering modeling
Other note
Parts
  • J. Koskinen, J. Pulliainen, M. Hallikainen, Land-Use Classification Employing ERS-1 SAR Data, Photogrammetric Journal of Finland, Vol. 14, No. 2, pp. 23-34, 1995. [article1.pdf] © 1995 Institute of Photogrammetry and Remote Sensing, HUT. By permission.
  • J. Koskinen, J. Pulliainen, M. Hallikainen, The Use of ERS-1 SAR Data in Snow Melt Monitoring, IEEE Trans. on Geoscience and Remote Sensing, Vol. 35, No. 3, pp. 601-610, 1997. [article2.pdf] © 1997 IEEE. By permission.
  • J. Koskinen, J. Pulliainen, M. Mäkynen, M. Hallikainen, Seasonal Comparison of HUTSCAT Ranging Scatterometer and ERS-1 SAR Microwave Signatures of Boreal Forest Zone, IEEE Trans. on Geoscience and Remote Sensing, Vol. 37 No. 4, pp. 2068-2079, 1999. [article3.pdf] © 1999 IEEE. By permission.
  • J. Koskinen, S. Metsämäki, J. Grandell, S. Jänne, L. Matikainen, M. Hallikainen, Snow Monitoring Using Radar and Optical Satellite Data, Remote Sensing of Environment, Vol. 69, No. 1, pp. 16-29, 1999. [article4.pdf] © 1999 Elsevier Science. By permission.
  • J. Koskinen, J. Pulliainen, M. Hallikainen, Effect of Snow Wetness to C-Band Backscatter - A Modeling Approach, Report 41, Laboratory of Space Technology, Helsinki University of Technology, Espoo, 20 p., 2000. [article5.pdf] © 2000 by authors.
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Permanent link to this item
https://urn.fi/urn:nbn:fi:tkk-002639