13 January 2021
Tracking the triggers for an epic dust storm
Published online 1 December 2020
The unusual weather conditions that produced a historic Saharan dust storm may be tied in part to the impact of global warming on Arctic sea ice.
For nearly a week in June, a colossal dust storm raged over the Sahara that would impact air quality and weather conditions on the other side of the planet. Researchers led by Diana Francis, at Khalifa University of Science Technology, in the United Arab Emirates have identified atmospheric factors underlying this record-breaking weather event, which could drive more extreme storms as the planet warms.
Francis has spent much of her career studying African dust storms. She and her team reviewed satellite images and atmospheric data spanning the 14–19 June 2020 event. She notes that many observers initially believed that the storm arose from localized, convective atmospheric movement. “These systems are known to produce spectacular dust storms during summer, over West Africa,” says Francis. “But our results showed this was not the case.”
Instead, this storm was fuelled by a high-pressure system that formed along the northwestern coast of the continent. This led to extreme intensification of the northeasterly winds that normally occur in the region, culminating in the massive dust storm known colloquially as ‘Godzilla’.
Climate change may also be a factor, where reduction of summertime sea-ice in the Arctic could ultimately contribute to the atmospheric anomalies observed in this study. “Changes in the temperature gradient between high latitudes and the subtropics or tropics are translated into changes in atmospheric circulation, which in turn can manifest as extreme events like the Godzilla dust storm,” says Francis. Her team is now looking into follow-on effects from this storm, including a possible role in 2020’s highly active hurricane season.
Francis, D. et al. The atmospheric drivers of the major Saharan dust storm in June. Geophys. Res. Lett. http://dx.doi.org/10.1029/2020GL090102 (2020).