Measurement of solifluction rates using multi‐temporal aerial photography

• Published in: Earth Surface Processes and Landforms
• Main Authors: Ridefelt, Hanna, Boelhouwers, Jan, Eiken, Trond
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: Kärkevagge; Låktatjåkka; Northern Sweden
• Online Access: http://dx.doi.org/10.1002/esp.1773; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fesp.1773; https://onlinelibrary.wiley.com/doi/pdf/10.1002/esp.1773

Abstract A new method is presented to assess decadal solifluction lobe movement and volumetric changes at the catchment scale. The method is based on photogrammetrical analysis of orthorectified repeat aerial photography in a geographic information system (GIS). High resolution aerial photographs from two valleys in northern Sweden, Kärkevagge and Låktatjåkka valleys, are used to quantify changes of the lobe fronts, as an indication of solifluction rates over a period of 41 years. Two methods are explored, the flow direction method and the front line method, in order to quantify the movement rates. Results show that the maximum combined root mean square error (RMSE) and resolution error amount to c. 1·7 m; no clear preference of one measurement method over the other was found. Application potential of the method is promising but reliability depends on the movement rates of the landforms and sufficient time span between the images. In the pilot study the measured yearly movement over the period 1959–2000 ranges from not‐detectable to 63 mm/yr. Not‐detectable means that movement cannot be detected within the resolution used in the study. Lobe advance rates are similar to measured surface movement rates and volumetric sediment flux by solifluction is found to be considerably lower than a previous estimate by Rapp (1960). Implications for lobe advance models are discussed. Photogrammetrical analysis is recommended as an important tool for detecting decadal solifluction movement at the catchment scale. Copyright © 2009 John Wiley & Sons, Ltd.