30 November 2023
Pinpointing storm triggers after the dust has settled
Published online 3 January 2023
An analysis of the severe dust storms that occurred over the Middle East in spring 2022 reveals an unusual atmospheric trigger.
There have been significant increases in dust storm intensity and length in the Middle East in the last few decades. Driven by increased desertification and changing global atmospheric conditions, dust storms present considerable health threats and disruption.
In May 2022, the Middle East experienced consecutive, severe dust storms that began over Iraq before moving into the south-eastern Arabian Peninsula. To determine the triggers and impacts of these storms, Diana Francis, at Khalifa University in the United Arab Emirates (UAE), and co-workers, combined data from satellite imaging and in-situ sensors. Their results indicate that the storms were driven by unusual atmospheric events in the mid-latitudes and over Turkey.
“This is a perfect example of how changes happening far away affect our region,” says Francis. “In the climate system, everything is connected, and feedback processes are critical.”
The team found that the dust storms were fuelled by two consecutive deep convection zones over the mountainous region of south-eastern Turkey. The convective systems were created by ‘cut-off’ low pressure zones – lows restricted to the upper atmosphere, closed off from the mid-latitude westerly jet. These formed over the eastern Mediterranean in mid-May, leading to unstable weather conditions on the ground. As the cut-off lows reached the mountains in Turkey, the resulting convective downdrafts led to intense winds lifting vast amounts of dust in Northern Iraq and Syria.
“A narrow dense band of moisture in the atmosphere, known as an atmospheric river, also flowed from tropical Africa into the Middle East along the eastern flank of the cut-off lows,” says Francis. “This supply of moisture helped maintain the cut-off lows for longer, exacerbating the duration and severity of the dust storms.”
Ground measurements at one UAE station showed that the dust storms caused a significant drop in shortwave radiation levels and a rise in longwave radiation. Dust particles tend to scatter sunlight, while trapping longwave radiation, preventing it from leaving the Earth’s surface. The storms increased night-time temperatures by 9 ºC, exacerbating the effects of spring heat. Together with the damage to human health from dust inhalation, and disruptions to daily lives, Francis hopes that these extreme events will prompt further research into dust particles and their effects on the Middle East climate.
“Most scientific research into dust to date has focused on other major sources, especially the Sahara and Asian deserts, because they impact highly populated areas,” says Francis. “With growing populations and rapid economic development in the Middle East, we need focused attention to prevent dust storms from worsening.”
Francis, D. et al. On the Middle East’s severe dust storms in Spring 2022: Triggers and impacts. Atmospheric Environment https://doi.org/10.1016/j.atmosenv.2022.119539 (2022).