DEM quality assessment for quantification of glacier surface change

Abstract Photogrammetric digital elevation models (DEMs) are often used to derive and monitor surfaces in inaccessible areas. They have been used to monitor the spatial and temporal change of glacier surfaces in order to assess glacier response to climate change. However, deriving photogrammetric DEMs of steep mountainous topography where the surface is often obscured by regions of deep shadow and snow is particularly difficult. Assessing the quality of the derived surface can also be problematic, as high-accuracy ground-control points may be limited and poorly distributed throughout the modelled area. We present a method of assessing the quality of a derived surface through a detailed sensitivity analysis of the DEM collection parameters through a multiple input failure warning model (MIFWM). The variance of a DEM cell elevation is taken as an indicator of surface reliability allowing potentially unreliable areas to be excluded from further analysis. This analysis allows the user to place greater confidence in the remaining DEM. An example of this method is presented for a small mountain glacier in Svalbard, and the MIFWM is shown to label as unreliable more DEM cells over the entire DEM area, but fewer over the glacier surface, than other methods of data quality assessment. The MIFWM is shown to be an effective and easily used method for assessing DEM surface quality.

[1]  Jim H. Chandler,et al.  Accuracy Assessment of Digital Elevation Models Generated Using the Erdas Imagine Orthomax Digital Photogrammetric System , 1999 .

[2]  P. Holmlund,et al.  The Mass Balance of Circum-Arctic Glaciers and Recent Climate Change , 1997, Quaternary Research.

[3]  M. Meier.  Contribution of Small Glaciers to Global Sea Level , 1984, Science.

[4]  Anne-Marie Nuttall,et al.  Photogrammetry as A Research Tool for Glaciology , 1997 .

[5]  R. Braithwaite,et al.  Glacier mass balance: the first 50 years of international monitoring , 2002 .

[6]  Bernard Lefauconnier,et al.  Glacier balance trends in the Kongsfjorden area, western Spitsbergen, Svalbard, in relation to the climate , 1999 .

[7]  Paul Cross,et al.  STATISTICAL CONCEPTS AND THEIR APPLICATION IN PHOTOGRAMMETRY AND SURVEYING , 2006 .

[8]  M. A. R. Cooper,et al.  Statistical concepts and their application in photogrammetry and surveying (continued) , 2006 .

[9]  S. N. Lane,et al.  Application of Digital Photogrammetry to Complex Topography for Geomorphological Research , 2000 .

[10]  B. Etzelmüller,et al.  Glacier geomorphometry — an approach for analyzing long-term glacier surface changes using grid-based digital elevation models , 1997, Annals of Glaciology.

[11]  Jim H. Chandler,et al.  Failure prediction in automatically generated digital elevation models , 2001 .

[12]  K. Richards,et al.  Developments in monitoring and modelling small‐scale river bed topography , 1994 .

[13]  Andrian J. Fox,et al.  Automatic Dem Generation for Antarctic Terrain , 2001 .

[14]  M. Meier,et al.  Mass balance of mountain and subpolar glaciers: a new global assessment , 1997 .

[15]  J. Moore,et al.  Changes in geometry and subglacial drainage of Midre Lovénbreen, Svalbard, determined from digital elevation models , 2003 .