Is Asian Dust Boosting Arctic Ice Melt?

When the wind whips up a dust storm in Asia, there is a reasonable chance that the sand will be blown to the Arctic. Now a study has shown the route that these Arctic-bound dust storms tend to travel. In recent years this weather pattern has become more common, and this constant sprinkling of Asian dust on Arctic ice could be one of the reasons the Arctic is warming so fast.

Many studies have shown that dust can travel a long way, with some revealing that it’s possible for dust to travel a full circuit around the globe. When the dust arrives at a new location it can bring all sorts of problems. As well as having an adverse effect on human health, the dust particles alter climate, by scattering and absorbing solar radiation and changing the probability of cloud formation. Asian dust has been recorded in ice cores and snow samples from Greenland, but until now there has been little investigation into how the dust is transported from Asia to the Arctic.

Zhongwei Huang from Lanzhou University in China and his colleagues used multi-sensor satellite and ground-based observations of one particular heavy dust storm over East Asia on 19 March 2010 to simulate the path that the dust took and the weather systems that carried it.

Their analysis revealed that the dust storm, which originated in the Gobi Desert, took an 's'-shaped path, travelling southeast across China, turning east and crossing Japan then turning back on itself to go northwest over Siberia, before finally swinging northwards to the Arctic. The dust took five days to complete the journey, hitching a ride on cyclones along the way. Huang and his colleagues also noticed that the Arctic oscillation index was negative during the storm, which enhances the East Asia Trough, creating stronger meridional and weaker zonal winds.

By studying dust events over the previous decade, the researchers discovered that the optimal weather conditions for transporting dust to the Arctic were very common. "Our study found that during more than one quarter of Asian dust events, dust was transported to the Arctic," says Huang, who published the findings in Environmental Research Letters (ERL). In recent years these weather conditions have become more common, perhaps due to climate change, and so it’s likely that the amount of Asian dust transported to the Arctic has increased.

The extent of Arctic sea ice has decreased rapidly since 1979, declining by up to 4.1% every decade. It is plausible that, by decreasing the albedo of the ice, the influx of Asian dust has contributed to this rapid melting. "Our study can help to explain some of the rapid warming in the Arctic, though it is important to remember there are several factors that can lead to rapid warming in the Arctic, not just Asian dust," says Huang.

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Taxonomy

• Glacier
• Climate Change
• Research