Why Is the Dust Activity in the Atacama Desert Low Despite its Aridity?

Abstract

AbstractThe Atacama Desert is amongst the driest places on Earth yet large dust outbreaks seem rare. We present the first quantitative assessment of dust events in the Atacama for 1950–2021 based on station observations. A total of 1920 dust days were recorded with less than 10% being classified as dust storms. We calculated the wind speeds at 5%, 25% and 50% of the dust‐event frequency distribution. The mean wind speed for the threshold of 5% is 10.9 ± 1.6 ms−1 which is twice as large as the values in the Taklamakan, Western Sahel, and Sudan, and consistent with the perceptually infrequent dust activity despite the exceptional aridity. We see no overall long‐term trend but increased dust activity for 1970–1978, 1984–1988 and 2013–2017. A combination of changes in the wind speed statistics and soil conditions, possibly including anthropogenic land‐use changes have led to the variability in dust activity.