Dynamics of East Antarctic glaciers from 1937-2017 analyzed using historical aerial expedition images

Since the beginning of the 20^th century, various countries have carried out expeditions to Antarctica with the aim of claiming territory, reconnaissance as well as capturing aerial images for topographic mapping. Many of these image inventories has since then been forgotten and never used for scientific purposes. We have gained access to a unique dataset of aerial images captured in 1936-1937 as a part of the Norwegian Thorshavn IV expedition surveying and mapping large parts of the East Antarctic coastline. The images have a stereo overlap of approximate 60% and are digitized using a photogrammetry-grade scanner, enabling us to produce the earliest known digital elevation models and orthophotos of Antarctica.

Expanding the observational records of Antarctic glaciers are vital for better understanding and modelling how changes in climatic parameters affects the ice. Currently, we know very little about the behaviour of Antarctic glaciers prior to the 1990s, due to a lack of large-scale observations. Several studies has proven the effectiveness of using digitally-scanned historical aerial images in studying ice mass losses of the pre-satellite era, but very few such studies exist for Antarctica. In this study, we explore Norwegian and Australian historical aerial expedition images collected between 1937 and 1997 to extensively expand the records and provide the earliest regional-scale Antarctic glacier records. The images are processed using structure-from-motion photogrammetry, which enables us to construct accurate, high-resolution digital elevation models and orthophotos. By combining expedition images with modern satellite data, we are creating a unique time-series dataset to study the changes of multiple glaciers along the East Antarctic coastline in Mac Robertson and Kemp Land between 1937 and 2017.