Washington, District of Columbia 2022-08-05 09:55:43 –
August 5, 2022
As glaciers around the world retreat due to climate change, national park managers need to know what’s ahead to prepare for the future. A new study by the University of Washington and the National Park Service measures his 38-year change in the glaciers of Kenai Fjords National Park, a stunning jewel about two hours south of Anchorage.
of studyA paper published Aug. 5 in The Journal of Glaciology found that 13 of the 19 glaciers have shown significant retreat, four are relatively stable and two are advancing. I was. You can also see trends in which types of glaciers are disappearing most rapidly. The approximately 670,000-acre park has a variety of glaciers, some ending in oceans, others in lakes and land.
“These glaciers are a big draw for tourists in the park. They’re one of the main things people come to see,” said the first author. Taryn Black, a UW PhD student in Earth and Space Sciences. “Park managers had some information from satellite imagery, aerial photography, and repeated photographs, but wanted a more complete understanding of changes over time.”
Data show glaciers terminating lakes containing popular glaciers. bear glacier When Pedersen Glacier, is retreating the fastest. The Bear Glacier has retreated 5 kilometers (3 miles) between 1984 and 2021, and the Pedersen Glacier has retreated 3.2 kilometers (2 miles) during that time.
“In Alaska, climate change is causing a lot of glaciers to retreat,” says Black. “These glaciers are at very low elevations. In addition to rising temperatures, we are likely to see more rain in winter rather than snow, consistent with other climate studies in the region.”
One surprising discovery was holgate glacierIt has progressed in recent years as a tidewater glacier that ends in the ocean. Local boat operators had reported seeing newly exposed land near the edge of the glacier in 2020. However, new analyzes show that the entire glacier has been advancing for about five years, with regular periods of advance and retreat. The edge of most other tidewater glaciers remained relatively stable during the study period.
All six glaciers responded moderately, with most retreating especially in the summer, but at a slower rate than the glaciers terminating the lake. The only other glacier to advance during the study period was the land-ending Pagna Glacier, which is covered in rock debris from the landslide caused by the 1964 Alaska earthquake. prevents it from melting.
To do the calculations, Black used 38 years of satellite imagery in the fall and spring to track the contours of each of the 19 glaciers. About 600 contours in total. She visually inspected each image to map the location of the edge of the glacier.Black recently used a similar approach research Calculate the rate of retreat of the terminal ocean glacier in West Greenland.
New data from Alaska provide a baseline for studying how climate change, including rising temperatures and changes in the type and amount of precipitation, will continue to affect these glaciers. All studied glaciers are considered marine glaciers as they are exposed to a warm and humid oceanic climate.
This research has immediate application to park managers. These numbers help quantify the changes that have occurred and will continue in the glacier and its immediate environment.
“You can’t manage your land well if you don’t understand the habitats and processes that occur on it,” says co-author Deborah Kurtz of the U.S. National Park Service in Seward, Alaska.
As the park’s Physical Sciences Program Manager, Kurtz is also interested in ecological changes in surrounding rivers, lakes, and landscapes, and how to communicate those changes to the public.
“Interpretation and education are also an important part of the National Park Service’s mission,” Kurtz said. “These data will allow us to provide scientists and visitors with more detail about the changes that are occurring on a particular glacier-by-glacier basis, giving everyone a better idea of the rate of landscape change we are experiencing in this region. It helps us to better understand and appreciate it.”
This research was conducted as part of an internship originally scheduled to take place in Kenai Fjords National Park. Black instead researched remotely from Seattle, Mount He visited a local glacier in Rainier. This research was funded in part by the National Park Service’s Future Park Leaders Program, a partnership between the Ecological Society of America and the US National Park Service.
New study calculates retreat of glacier edges in Alaska’s Kenai Fjords National Park Source link New study calculates retreat of glacier edges in Alaska’s Kenai Fjords National Park