Tuesday, October 1, 2019

NIF shrinkage: 2015-2019

The right-hand image above depicts Kilimanjaro's Northern Icefield in mid-September (2 weeks ago). Although resolution is not ideal, minimal snowcover allows comparison with the same glacier four years earlier (July 2015). Note that the two images are not perfectly registered, so the following observations are qualitative.

Both the north and south remants of the icefield have decreased in area, especially relatively-thin portions at lower elevations. These include the northwest part of the north remnant, and the western margin of the southern part. A marginal meltwater lake is visible at the southern margin of the north portion on both images, and has been present for many years. At the eastern edge, we have observed shrinkage of several isolated blocks of ice over the years; these were present in 2017, but have now disappeared. On the south portion, thin areas and holes in the left-hand image are now ice free, including one location (southeast margin) where we have evidence that geothermal heat initiated hole formation.

The rate of glacier thinning was reduced during 2018, due to above-normal snow accumulation and the attendant increase in albedo. To illustrate, note the brighter, high-elevation portions of the glacier in the 2015 image; this is snow cover over old glacier ice.

We are hoping to visit the summit glaciers early in 2020 to measure ablation stakes, conduct GPS surveys, and photographically document changes to the glaciers since our last visit.

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