Long-term records of Antarctic outlet glacier dynamics from historical data and novel remote sensing techniques

Abstract

Quantifying how the cryosphere responds to various climate forcings is essential in accurate forecasting of ice sheet stability as well as sea level rise. In order to better predict how future climates will impact ice sheet and glacier mass balance, it is first necessary to understand whether the observed changes in glaciers are from internal dynamics or responses to climate forcings. Equally necessary is the ability to identify if current glacier transformations are due to discrete events or ongoing phenomena. Unfortunately, most records for the world’s glaciers only extend for the last two decades, thus making long-term projections difficult. The overall aim of each project is to improve our understanding of cryosphere-climate relationships through long-term observational records and numerical modeling. The three projects are: (1) validating the use of historic aerial imagery with modern-day image processing techniques and manually extracted ground control from high-resolution imagery; (2) quantifying ~60-year surface elevation changes of outlet glaciers flowing through the Transantarctic Mountains from trimetrogon aerial photos; and (3) investigating basal crevasse initiation and determining if the formation of anomalously large crevasses can be proxies for historic Antarctic subglacial flooding events. The first project uses historic vertical aerial imagery and high-resolution optical satellite imagery; the second employs oblique aerial imagery from the 1960s and high-resolution optical satellite imagery; and the last project relies on a combination of airborne radar, in situ GPS, and optical satellite imagery. Innovative remote sensing techniques are used to acquire information that is either analyzed or integrated into numerical models (depending on the project) to draw conclusions about the stability of the ice sheet. These results further our understanding of the manner in which ice sheets and glaciers respond to changes in climate and will ultimately allow for more accurate constraints in modeling future sea level rise.