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A surface coating of hollow glass microspheres (HGMs) on freshwater pond ice increased the average daily albedo 0.17 → 0.36
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The coating of HGMs reduced the rate of ice melt by 33% from 5 March through 19 March
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Applied early in the season, HGMs can withstand weathering of a northern climate, reemerging after snowmelt to brighten the ice surface
[media] A method to increase ice retention on pond ice has been tested during the Spring melt season. The test has shown the potential to slow ice loss by using a thin layer of a safe, commonly used reflective material. This albedo-enhancing approach shows potential to help preserve ice in selected regions in the Arctic and elsewhere, potentially slowing world-wide rates of global warming and reducing climate instabilities.
Loss of reflectivity in the Arctic and the wider cryosphere is known to increase global temperature rise through an ice-albedo feedback loop, which has the potential to lead to loss of summertime ice cover in the Arctic Ocean, and to accelerate global warming. Despite the urgency of this situation, there are few options being developed to preserve and restore ice reflectivity. Localized surface albedo modification using reflective materials offers a potential pathway to restore Arctic ice.
We conducted a controlled experiment to determine effects of surface albedo modification on ice melt and thermodynamic processes of a pond. We applied a coating of hollow glass microspheres (HGMs) to a test section, while leaving a control section unmodified. Laboratory measurements show that the loading of HGM materials used corresponds to a reflectivity of 30%. We measured ice and snow thickness, albedo, incoming and outgoing shortwave and longwave radiation, and ice, water, and ambient temperatures. A 1-D thermodynamic model was developed to quantify the effect of albedo modification on the processes of heat transfer, energy absorption and ice melt.
The albedo increased from 0.17 on a control section to 0.36 on a test section. During the 2-week melt period, there was a 29% reduction in net radiative energy into the test section and a 33% reduction of ice melting rate measured by volume.
This experiment using quantitative methods elucidates the mechanisms of ice preservation through surface albedo modification and demonstrates its effectiveness.
…For this study, we used the same small, private pond in Minnesota used in previously reported field studies ( et al 2018).
…Prior laboratory and field testing in Minnesota and the Arctic primarily used K1 microspheres, part of the 3M™ Glass Bubbles product family. Our aim is to evaluate widely available materials obtainable from multiple sources, which leads to availability of long-term safety information, and potential consideration of future application on a larger scale. In this project we commissioned laboratory evaluations of several available HGM products. The measurements, detailed in Supporting Information S1, included reflectivity under wet and dry conditions, and particle size distribution. The material chosen for use in this study was Potters Sphericel (R) 25P45.
…Figure 3 shows the aerial views of the pond taken over 11 days during the melt period. The original deposition pattern of rows of 1.5 m × 1.5 m squares is quite evident and shows that the HGMs essentially maintain their position during most of the melt process. The area of the pond covered with ice decreased over time, with faster ice area loss on the untreated control side. On the evening of March 16th there was a snowfall and refreeze of the entire area of the pond. A sharp increase in albedo for 17 March was observed from this event, as seen in Figure 2a, which also indicates that fresh snow has higher albedo than either ice or the HGM treatment. However, this temperature drop created only thin ice over the previously thawed area of the pond and was too thin to show a difference ice thickness data. By 19 March the refrozen area had thawed again, and on March 20th the entire control side of the pond thawed.