Assertion: glacier's zone | /r/AtLocation | satellite observations
Facets:
value: over the last two decades
type: TEMPORAL
Source sentences:
text: Glacier algal blooms on the Greenland Ice Sheet are so extensive that their presence in the surface ice is thought responsible for widespread darkening along the western margin of the ice sheet known as the 'dark zone' that has appeared in satellite observations over the last two decades.
text: Glacier algal blooms on the Greenland Ice Sheet are so extensive that their presence in the surface ice is thought responsible for widespread darkening along the western margin of the ice sheet known as the 'dark zone' that has appeared in satellite observations over the last two decades.