Dust storms found as "hidden drivers" of extreme rainfall and precipitation shifts

LANZHOU, April 30 (Xinhua) -- A new study by Chinese scientists has uncovered that dust storms are the "hidden drivers" of extreme rainfall and precipitation shifts on a global scale, overturning the long-held perception of dust storms as merely natural disasters.

This study elucidates the regulatory mechanism by which dust influences precipitation under human activity, providing fresh insights into the causes of the frequent occurrence of extreme weather events globally, according to Lanzhou University.

The study was conducted by a team from the College of Atmospheric Sciences at Lanzhou University, in collaboration with the weather modification center of China Meteorological Administration and the Liupanshan atmospheric science field observation and research station. Its findings have been published online in the journal Science Advances.

It is based on global observations of dust events combined with global precipitation data analysis and numerical modeling to draw comprehensive conclusions. It features specific case studies on two representative regions including the Taklamakan Desert, China's largest desert in Xinjiang Uygur Autonomous Region, as a dust-source region, and north China as a dust-transport region, according to Liu Yuzhi, a professor at Lanzhou University and leader of the study.

Multiple evaluation methods were employed to enhance the reliability of the findings. Through high-precision numerical simulations, the study revealed the physical mechanism by which dust affects precipitation. It confirms that dust particles can act as efficient ice nuclei, promoting the ice crystal formation in clouds and significantly enhancing precipitation efficiency through "ice crystal effect."

The study revealed the dual effects of global dust storms from both observational and numerical perspectives, indicating that behind the disasters lies a hidden benefit of precipitation. It also highlighted the key regulatory role of dust activity in arid regions in the global water cycle.

It also found that against the backdrop of elevated anthropogenic aerosol concentrations, dust has become a core factor determining global precipitation patterns.

Over the past four decades, dust events have exhibited approximately 10-year periodic oscillations, with precipitation in the week following these events being significantly higher than under dust-free conditions.

The study showed that particles released into the atmosphere during dust storms can serve as highly efficient atmospheric ice nuclei, promoting ice crystal formation in clouds and enhancing precipitation efficiency. Amid heightened pollution from intensified human activity, dust particles can help offset the decline in light precipitation associated with increased anthropogenic aerosols, while also contributing to a higher frequency of heavy rainfall.

Liu explained that amid global warming and increasing industrial pollution, there are more and more anthropogenic particles in the atmosphere. These particles cause clouds to contain "super-cooled water" that has dropped below zero degrees Celsius yet stubbornly "refuses" to freeze. This super-cooled water has difficulty transforming into rain or snow on its own. At this point, dust storms ironically become the "savior" that drives them to fall.

"To put it simply, as pollution increases, water in clouds refuses to freeze; when dust arrives, it can actually 'prompt' them to rain," Liu said.

She noted that, in the context of global warming, the frequency and intensity of extreme weather events, such as dust storms and heavy rainfall, are changing. This study provides a new attribution approach for such events.

The study also established a theoretical framework for "dust-cloud-precipitation-interactions" from regional to global scales, advancing the mechanistic understanding of dust's role in global precipitation processes and providing scientific support for water resource management and disaster prevention efforts.

"It could play a role in dust storm research and forecasting by helping improve the accuracy of hydrological cycle simulations in weather forecasting. It also reminds us to pay attention to heavy precipitation forecasting and risk assessment," Liu added.