70 years of high-resolution glacier surface elevation records derived
from historical aerial photography across Western North America
Abstract
We present interannual to decadal glacier and geomorphic change
measurements at multiple sites across Western North America from the
1950s until present. Glacierized study sites differ in terms of glacial
geometry and climatology, from continental mountains (e.g., Glacier
National Park) to maritime stratovolcanoes (e.g., Mt. Rainier).
Quantitative measurements of glacier and land surface change are
obtained using the Historical Structure from Motion (HSfM) package. The
automated HSfM processing pipeline can derive high-resolution (0.5-2.0
m) Digital Elevation Models (DEMs) and orthomosaics from historical
aerial photography, without manual ground control point selection. All
DEMs are co-registered to modern airborne lidar and commercial satellite
stereo reference DEMs to accurately measure geodetic surface elevation
change and uncertainty. We use scanned historical images from the USGS
North American Glacier Aerial Photography (NAGAP) archive and other
aerial photography campaigns from the USGS EROS Aerial Photo Single
Frames archive. We examine the impact of regional climate forcing on
glacier volume change and dynamics using downscaled climate reanalysis
products. By augmenting the record of quantitative glacier change
measurements and better understanding the relationship between climate
forcing and heterogeneous glacier response patterns, we aim to improve
our understanding of regional glacier mass change, as well as inform
management decisions impacting downstream water resources, ecosystem
management, and geohazard risks.