Buffering-based analysis of calving front of Jakobshavn isbræ, West Greenland

Calving front is one of glacier's features that reflects current pattern of climate change, hence it has been consistently measured and mapped for long decades. Especially, the recession and advance of its position has been investigated in many studies because it is highly related to glacier's volume change. However, conventional methods that applied in those researches retained insufficient representativeness or objectiveness to determine its frontal position. Meanwhile, there were relatively few researches to quantize and study the intensity of calving event because of the difficulty to quantize its intensity. Calving process is the most factor of calving front's retreat in fast-flowing glaciers so that this factor should be inspected more thoroughly. In order to deal with those issues, buffering-based method was proposed in this study and the calving front of Jakobshavn Isbræ, West Greenland was analyzed as a case study. Buffering-based method, which analyzes relative distance between two linear features, has more objectivity because it avoids arbitrary decision which can cause distorted analysis result. Moreover, this method is capable of produce additional parameter about calving front's shape change, which can be utilized to quantize the intensity of calving. From the analysis result of calving front that has changed for years, it was found that the position of calving front has drastically retreated from summer of 2002. Moreover, two largest calving events during the observation period were detected to be occurred in the same period when the large retreat has observed. Therefore, it is expected that buffering-based method can improve quality of the analysis and facilitate another aspects of glacier study.