| Title: |
The Role of Ice‐Rafted Debris (IRD) on Icebergs' Deterioration. |
| Authors: |
Ward, Nash; Cenedese, Claudia; McElwaine, Jim N.; Condron, Alan |
| Source: |
Geophysical Research Letters; 5/16/2026, Vol. 53 Issue 9, p1-7, 7p |
| Subject Terms: |
ICEBERGS; TURBULENT heat transfer; ICE calving; SMOKE plumes; ABLATION (Glaciology); GLACIATION; OCEAN; GLACIAL drift |
| Geographic Terms: |
NORTH Atlantic Ocean |
| Abstract: |
During the last ice age, icebergs transported Ice‐Rafted Debris (IRD) more than 3,000 km across the North Atlantic. However, their effect on the deterioration of icebergs and thus where the deposits form is poorly understood. Laboratory experiments and a predictive model (with no fitting parameters) investigating the effects of sediment on iceberg deterioration found that IRD increase the melt rate in three ways. First, the melt rate of the sediment layer is 1/1−ϕs $1/\left(1-{\phi }_{s}\right)$ larger because there is less ice to melt, where ϕs ${\phi }_{s}$ is the sediment volume fraction. Second, the melt rate of the sediment layer and ice layer below is almost three times larger due to a sediment plume which enhances the turbulent heat flux toward the ice. Third, a sediment layer can cause an iceberg to break into two pieces, increasing the total surface area and causing the overall melt rate to increase as much as 50%–60%. Plain Language Summary: During the last ice age, icebergs carried rock fragments, sand, and other sediment—called Ice‐Rafted Debris (IRD)—over long distances, more than 3,000 km, across the North Atlantic. But scientists still don't fully understand how this debris affects how icebergs melt and where the debris eventually gets deposited. Laboratory experiments and a prediction model show that having sediment on an iceberg makes it melt faster in three main ways: (a) Less ice to melt: A layer of sediment means part of the iceberg is not ice. Because of this, the remaining ice in that layer melts faster. (b) Faster melting from water movement: The sediment creates a plume in the water that increases turbulence—basically stirring the water near the ice. This extra movement brings more heat to the ice, making it melt almost three times faster. (c) Iceberg breakup: Sometimes, the sediment layer causes the iceberg to split into two pieces. This increases the total surface area exposed to water and can boost the overall melting rate by up to 50%–60%. Key Points: Layers of IRD reduce the ice volume in that layer, causing more rapid melting under equivalent heat flux conditionsIRD induced turbulent plumes nearly triple the melt rates in the IRD layer and the ice below by enhancing the ocean‐ice heat exchangeDifferent melt rates between IRD layers and IRD‐free ice can cause the icebergs to split into two pieces, increasing melting up to 60% [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |