The Humboldt Glacier in Greenland has experienced an unusual late-season phenomenon in 2023, resulting in a complex interplay of ice, firn, meltwater, and sediment. Traditionally, the period from May to early September witnesses the annual melting process across Greenland’s expansive ice sheet. However, as August drew to a close in 2023, unseasonably warm temperatures triggered several days of significant melting. This atypical late-season event reached its zenith on August 22, covering an extensive area of approximately 282,000 square miles (730,000 square kilometers), or roughly 45 percent of the ice sheet’s surface, as reported by the National Snow and Ice Data Center.
A Comparative View of Humboldt Glacier
A pair of satellite images provides a stark comparison of the Humboldt Glacier’s front in northwest Greenland before and after the peak of late-season melting. Captured on August 18 (upper) and August 27 (lower) by the Operational Land Imager (OLI) on Landsat 8, these images reveal notable changes. By August 27, the recent snow and underlying compressed snow, known as firn, have receded, exposing more ice stained with dirt, appearing in shades of gray and brown. Further inland, the darkest blue areas indicate saturated firn, melt ponds, and possibly temporary streams. The intermediate zones may consist of slushy wet firn mixed with areas where water has either drained or refrozen. Beyond its implications for rising sea levels, meltwater can infiltrate the base of the ice sheet through crevasses and moulins, hastening the flow of ice toward the ocean.
Expert Evaluation
Christopher Shuman, a glaciologist affiliated with the University of Maryland, Baltimore County, and stationed at NASA’s Goddard Space Flight Center, conducted a comprehensive analysis of the two satellite images. In summary, he characterized the affected region as a complex amalgamation of ice, firn, meltwater, and sediment.
Comparison with Previous Melting Seasons
Throughout June and July, a sustained period of above-average melting occurred, placing the season in line with several other high-melt years in recent memory. However, the late August surge in melting expanded the cumulative melt area further, ultimately ranking as the second-largest in the 45-year satellite record, surpassed only by the exceptional year of 2012.
Historical Context of Late-Season Melting
It’s worth noting that late-season melt events have transpired before, notably in September 2010. That particular event propelled the season towards a more significant cumulative melt compared to the 2023 season at the onset of September.
Implications of Late-Season Melting
Late-season melting not only contributes to the cumulative losses within a single season but can also exert influence on future melt seasons. A prolonged melt season delays the accumulation of surface snow, subsequently impacting the intensity of melting at the outset of the following season.
Image credit: NASA Earth Observatory images by Wanmei Liang, utilizing Landsat data from the U.S. Geological Survey.
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Frequently Asked Questions (FAQs) about Glacial Melting in Greenland
What caused the late-season melting at Humboldt Glacier in Greenland in 2023?
Unseasonably warm weather in late August 2023 triggered the late-season melting at Humboldt Glacier in Greenland, resulting in a mix of ice, firn, meltwater, and sediment.
How extensive was the late-season melting event?
The late-season melting event on August 22, 2023, covered nearly 282,000 square miles, accounting for approximately 45 percent of the ice sheet’s surface in Greenland.
Who conducted the analysis of the satellite images of Humboldt Glacier?
The analysis of the satellite images was carried out by Christopher Shuman, a glaciologist affiliated with the University of Maryland, Baltimore County, and working at NASA’s Goddard Space Flight Center.
How does late-season melting impact future melt seasons?
Late-season melting has the potential to delay the accumulation of surface snow, which can, in turn, affect the intensity of melting at the start of the next melt season.
Is this late-season melting event a unique occurrence?
Late-season melting events have occurred in the past, with one notable event in September 2010. However, the 2023 event ranked as the second-largest in a 45-year satellite record, following only the exceptional year of 2012 in terms of cumulative melt area.
What are the implications of such melting for climate change and sea levels?
Late-season melting, along with other forms of glacial melt, contributes to rising sea levels. It can also impact the overall climate system by altering the ice sheet’s dynamics and influencing future weather patterns.
More about Glacial Melting in Greenland
- National Snow and Ice Data Center
- NASA’s Goddard Space Flight Center
- University of Maryland, Baltimore County
- NASA Earth Observatory
- U.S. Geological Survey
