Detection of spatial, temporal, and spectral surface changes in the Ny-Ålesund area 79 N, Svalbard, using a low cost multispectral camera in combination with spectroradiometer measurements.

Updated 2003-01-29

Changes in surface reflection at the arctic tundra at Ny-Ålesund, Svalbard (79 N) were monitored during the melting season 2002 using a low cost multispectral digital camera with spectral channels similar to channels 2, 3, and 4 of the Landsat Thematic Mapper satellite sensor. The camera was placed 474 m above sea level at the Zeppelin Mountain Research Station and was programmed to take an image automatically every day at solar noon. To achieve areal consistency in the images (which is necessary for mapping purposes) the images were geometrically rectified into multispectral digital orthophotos. In contrast to satellite images with high spatial resolution the orthophotos provide data with high spatial and high temporal resolution at low cost. The study area covers approximately 2 km2 and when free of snow, it mainly consists of typical high arctic tundra with patchy vegetation and bare soil in between. The spectral information in the images was used to divide the rectified images into maps representing different surface classes (including three subclasses of snow). By combining classified image data and ground measurements of surface reflectance, a model to produce daily maps of surface albedo was developed. The model takes into account that snow-albedo decreases as the snow pack ages; and that the albedo decreases very rapidly when the snow pack is shallow enough (20-30 cm) to let surface reflectance get influenced by the underlying ground. Maps representing days with no image data (due to bad weather conditions) were derived using interpolation between pixels with equal geographical coordinates. The time series of modeled albedo-maps shows that the time it takes for the albedo to get from 80% to bare ground levels varies from less than 10 days in areas near the coast or in the Ny-Ålesund settlement till more than 70 days in areas with large snow accumulations. For the entire study area the mean length of the 2002 melting period was 28.3 days with a standard deviation of 15.1 days. Finally, the duration of the snowmelt season at a location where it is measured routinely, was calculated to 23 days, which is very close to what is the average for the last two decades.

Time frame

Status
Completed
Project time span
2002 - 2002
Data collection
not specified
Data processing
not specified
Data reporting
not specified

Contact information

Contact person
Birger Ulf Hansen
Address
Institute of Geography University of Copenhagen Øster Voldgade 10 1350 Copenhagen Denmark
Phone
+45 35322519
Fax
+45 35322501
Email
kd.uk.rgoeg@hub
Other project contacts
Jørgen Hinkler jh@geogr.ku.dk Jon Børre Ørbæk jonbo@npolar.no

Parameters and Media

Not specified

Geography

Regions studied
Svalbard
Sverdrup Research Station, Ny-Ålesund

Data availability

Samples/specimens archived in specimen banks?
No

Methods & Procedures

Not specified

Additional Information

Is this a bi- AND multi-lateral project (i.e. a project involving cooperation between different countries)?
No
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