Status of Glaciers in the Western United States based on Sentinel-2A
Images and Machine Learning Algorithm
Abstract
In this study, we employed random forest machine learning classification
to assess the current state of glaciers in the western United States
using Sentinel-2A satellite imagery. By analyzing Sentinel-2A imagery
from September 2020 and comparing it to the RGI inventory, the study
determined the current conditions of the glaciers. Our findings unveiled
a significant reduction in both glacier area and volume in the western
United States since the mid-20th century. Currently, the region hosts
4091 glaciers spanning seven states, covering a total area of 432.01 km2
with a corresponding volume of 9.02 km3. During the study period, a loss
of 237.07 km2 in glacier area was observed, representing a 35.43%
decrease when contrasted with the RGI boundaries. The volume lost during
this period amounted to 4.9 km3, roughly equivalent to 4.7 gigatons of
water. Among the states, Washington experienced the most significant
glacier area reduction, with a loss of 130.06 km2. Notably, glaciers in
the North Cascade Range of Washington, such as those in Mt. Baker and
Mt. Shuksan, now cover, on average, only 85% of their original glacier
boundaries with ice and snow at the conclusion of the 2020 hydrological
year. Major glaciers, including the White River glacier, West Nooksack
glacier, and White Chuck glacier, have lost more than 50 percent of
their original area.