This graph summarizes the annual (year-to-year)
surface height change and cumulative surface height change from 1993 to 2019. The vertical red
and green bars show the surface height change compared to the
previous year. For example, the surface height of the Taku
Glacier at Profile 4 decreased an average of 2.79 meters from July 25, 2018 to July
The blue line plot is the cumulative surface height change
relative to the first GPS survey in 1993. For each year, it indicates how much higher or lower the surface was when compared
to the baseline year of 1993. For example, the surface at
Profile 4 was 11.69 meters lower on July 25, 2019 than it was on
July 25, 1993.
After 27 years of detailed GPS surveying at Profile 4, a pattern
showing both positive and negative surface height change from
1993 to 2012 is seen. During these years, annual
(year-to-year) surface height alternately varied from +2.03 meters to
-1.64 meters, with the cumulative change from 1993 to 2012
being -1.85 meters. However, negative surface
height changes have occured every year since 2012. The time
period from the summer of 2012 to the summer of 2013 seems to be
the inflection point at which the thinning of the Taku Glacier
has drastically increased. As
of July 25, 2019, the surface elevation of the Taku Glacier at
the location of Profile 4 is 11.69 meters lower than it was in
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