Automated production of high-resolution DEMs from historical imagery for
quantitative analysis of glacier and geomorphological change
Abstract
We are developing a fully automated Structure from Motion (SfM)
processing pipeline to generate high-resolution digital elevation models
(DEMs) from archives of historical aerial and satellite imagery acquired
between the 1950s to the 1990s. Scanned images are loaded directly from
online archives and processed using open-source software deployed on
cloud-computing infrastructure. Modern DEMs with high resolution and
accuracy (e.g., airborne lidar, stereo DEMs from sub-meter satellite
imagery) are used to iteratively improve historical image geolocation,
without manual processing steps involving ground control. We present
preliminary DEM and orthoimage time series for glaciers in Washington
state, derived from the USGS North American Glacier Aerial Photography
(NAGAP) archive. These records document surface elevation change with
sub-meter vertical accuracy over decadal timescales. We are using these
observations to quantify evolving rates of glacier mass change and
proglacial sediment transport. Our aim is to generate long-term,
regional records of glacial response to climate forcing on decadal
timescales. Better understanding these past responses will help
constrain projections of future glacier change under different climate
scenarios, as well as impacts on downstream water resources.