Change points detected in decadal and seasonal trends of outlet glacier terminus positions across West Greenland

• Published in: Remote Sensing
• Main Authors: York, Ashley V., Frey, Karen E., Jamali, Sadegh, Das, Sarah B.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: MDPI 2020
• Subjects: Marine-terminating glacier; Landsat; Change point detection; DBEST; Greenland; glacier; Sea ice; Uummannaq
• Online Access: https://hdl.handle.net/1912/26517

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in York, A., V., Frey, K. E., Jamali, S., & Das, S. B. Change points detected in decadal and seasonal trends of outlet glacier terminus positions across West Greenland. Remote Sensing, 12(21), (2020): 3651, doi:10.3390/rs12213651. We investigated the change in terminus position between 1985 and 2015 of 17 marine-terminating glaciers that drain into Disko and Uummannaq Bays, West Greenland, by manually digitizing over 5000 individual frontal positions from over 1200 Landsat images. We find that 15 of 17 glacier termini retreated over the study period, with ~80% of this retreat occurring since 2000. Increased frequency of Landsat observations since 2000 allowed for further investigation of the seasonal variability in terminus position. We identified 10 actively retreating glaciers based on a significant positive relationship between glaciers with cumulative retreat >300 m since 2000 and their average annual amplitude (seasonal range) in terminus position. Finally, using the Detecting Breakpoints and Estimating Segments in Trend (DBEST) program, we investigated whether the 2000–2015 trends in terminus position were explained by the occurrence of change points (significant trend transitions). Based on the change point analysis, we found that nine of 10 glaciers identified as actively retreating also underwent two or three periods of change, during which their terminus positions were characterized by increases in cumulative retreat. Previous literature suggests potential relationships between our identified change dates with anomalous ocean conditions, such as low sea ice concentration and high sea surface temperatures, and our change durations with individual fjord geometry. Partial support for this research was provided by NASA Earth and Space Science Fellowship Award NNX12AO01H and National Science Foundation Award 1205018 to K.F. S.J. was funded by Knut ...