Tristram Irvine-Fynn is quantifying High-Arctic glacier surface change during the autumn
Today, the Arctic is getting warmer and wetter. Climate models predict this trend will continue into the future. Such a change will undoubtedly affect the region’s glaciers. Yet, surprisingly, current knowledge of how glacier surfaces respond to rainfall is remarkably limited. This is particularly true for the autumn season transition. Rainfall influences melting and the total meltwater volumes released from a glacier. Rain before winter may also define the nature of the glacier surface that is then frozen and only re-exposed to melt processes in the following summer once the seasonal snow has gone. My Leverhulme Trust Research Fellowship allows me to address these unknowns by measuring how an Arctic glacier surface responds to autumn rainfall.
During summer, we know glacier melt is driven primarily by solar radiation, and the glacier surface develops a complex topography. This topography is linked to the distribution of light-absorbing impurities such as mineral dust blown onto the ice by wind. However, in the autumn transition, warm air temperatures coupled with clouds and rainfall weaken the dominance of solar radiation as the main driver of glacier melt. The ice surface becomes smoothed, removing the varied topography and redistributing the impurities. However, this process of ‘resetting’ has not been quantified.
The Fellowship will focus on a glacier in Svalbard in the Norwegian Arctic. I will use a drone to photograph the glacier surface repeatedly over a three-week period in the autumn transition period when rainfall events are highly likely. Using cutting-edge photogrammetric technologies, I will manipulate these images to create accurate three-dimensional digital elevation models of the glacier surface to describe the topography. From these data, spatial analyses will allow me to define changes in both topography and impurity distribution, and to associate these changes with meteorological conditions recorded at local weather stations.
To understand if further alterations of the glacier ice surface occur during winter months, I will revisit the site in spring and use geophysical tools to survey the ice topography beneath the seasonal snowpack. By digging snow pits and exposing the glacier ice, I will confirm the results of the geophysical surveys and use digital imaging to compare to the ice surface recorded in the autumn drone images.
My research will reveal how glacier surfaces react to autumn rainfall. Doing this will provide novel and essential information to improve our models used to forecast Arctic glaciers’ response to an increasingly wet regional climate.
Using AgiSoft PhotoScanTM to convert a series of overlapping aerial images of a glacier surface (indicated by the blue rectangles) into a fully three-dimensional digital elevation model using so-called Structure-from-Motion photogrammetry.
