February 13, 2019
Boydell Glacier, Antarctica retreat in Landsat images from 2001 and 2017, terminus in 2001 at red dots in 2017 at yellow dots. A-E are reference points.
Boydell Glacier flows east from the northern Antarctic Peninsula and prior to the 1980’s was joined with the Sjogren Glacier as a principal feeder glacier to Prince Gustav Ice Shelf. This 1600 square kilometer ice shelf connecting the Peninsula to James Ross Island disintegrated in the mid-1990’s and was gone by 1995 (Cook and Vaughan, 2010). Scambos et al (2014) noted a widespread thinning and retreat of Northern Antarctic Peninsula glaciers with the greatest changes where ice shelf collapse had occurred, Boydell/Sjogren Glacier being one of the locations. A new paper by Seehaus et al (2016) focuses on long term velocity change at Sjögren Glacier as it retreated. This study illustrates the acceleration after 1996 from 0.7 m/day to 2.0 m/day in 2003 and then after separation Boydell Glacier, which is slower, has declined from a velocity of 1.6 m/day in 2007 to a velocity of 1.0 km day in 2015. Here we examine Landsat images from 1990, 2001, 2005 and 2017 to illustrate changes in terminus position of Boydell Glacier.
In the 1990 Landsat image Boydell/Sjögren Glacier feed directly into the Prince Gustav ice Shelf which then By 1993 Seehaus et al (2016) note that Boydell/Sjögren Glacier had retreated to the mouth of Sjögren Inlet in 1993, this is marked Point A on Landsat Images. By 2001 the glacier had retreated to Point B, a distance of 7 km. Between 2001 and 2005 a 2.5 km ot 3 km retreat led to a separation of Boydell Glacier and Sjogren Glacier and a retreat to Point C. In 2017, Boydell Glacier has retreated 6.5 km since 2001. This is less then the Sjögren Glacier retreat of 10-11 km from the 2001 location. Seehaus et al (2016) Figure 1 indicates that the area of high velocity over 1.0 m/day on Boydell Glacier in the last decade extends the entire 12 km length of the valley reach, which is fed by an icefall from a higher plateau region. The high velocity and limited change in fjord width in the lower 6 km indicates there is not a new pinning point to slow retreat appreciably in this stretch. Figure 1 also illustrates the retreat from 1993-2014. The pattern of ice shelf loss and glacier retreat after loss has also played out at Jones Ice Shelf and Rohss Bay.
2005 Landsat Image of Boydell/Sjogren Glacier terminus marked by red dots.
Antarctic REMA Explorer view of Boydell (B) and Sjogren (S) in 2002.