Newswise — Associate Professor Jing Li from Peking University's School of Physics headed a research team that recently released a paper titled "North Tropical Atlantic Variability: Key Factor for Decadal Shift in Middle East Dust Activities" in Science Bulletin. Their study demonstrates that the variability in sea surface temperature (SST) within the North Tropical Atlantic plays a central role in driving the decadal trend shift observed in dust activities within the Middle East.
As the world's second-largest dust source, the Middle East plays a significant role in global dust emissions, contributing to over 10% of the total. Particularly during the summer season, there is a pronounced peak in dust activity. The transportation of these dust particles has far-reaching consequences, affecting densely populated regions from North America to South Asia, and causing detrimental effects on transportation, health, agriculture, and the environment. In the past two decades, a thorough analysis of data from multiple sources has revealed a substantial shift in summer dust activity in the Middle East. Prior to approximately 2010, there was a notable increase in dust activity, which then transitioned to a marked decline (see Figure 1). Despite this observation, the underlying reasons for this shift have remained unclear. Therefore, it is of utmost importance to investigate and comprehend the factors responsible for this trend transition, as well as to explore the specific mechanisms that drive these impacts. This research is crucial for enhancing our understanding of global climate and environmental change.
To investigate this phenomenon, Associate Professor Jing Li and their research team from Peking University's School of Physics utilized a combination of global climate model simulations and extensive analysis of data from various sources. Their comprehensive study unveiled a strong association between the shift in Middle East dust activities and fluctuations in sea surface temperature (SST) within the North Tropical Atlantic. The correlation coefficient between the two variables surpassed 0.6, while no significant correlation was found between dust activities and SST variability in other ocean basins. Notably, both Middle East dust and North Tropical Atlantic SST displayed a parallel transition from increasing to decreasing decadal trends during the period from 2000 to 2019, with the turning point occurring around 2010. Through forced simulation experiments that incorporated observed North Tropical Atlantic SST and employed a random forest dust prediction model, the research team successfully replicated the decadal trend shift in dust activities within the Middle East over the past two decades.
Through further investigations, the research group delved into the diagnosis of meteorological variables and physical processes, uncovering key insights. They found that the warming of the North Tropical Atlantic triggers an abnormal meridional circulation pattern in the region. This circulation pattern promotes upward airflow in the North Tropical Atlantic and downward airflow in the Middle East. As a result, surface high pressure is formed, accompanied by intensified Shamal winds in the northern areas. These winds, generated by the descending airflow, create a hot and dry environment in the Middle East, which is favorable for the emission and transportation of dust particles. Notably, around 2010, when the sea surface temperature in the North Tropical Atlantic shifted from increasing to decreasing, there was a simultaneous alteration in the trend of dust activity in the Middle East.
The research conducted not only provides valuable insights into the potential factors driving the decadal variability of dust activity in the Middle East but also establishes a solid theoretical foundation for improving predictions of dust activity both in the region and on a global scale. By understanding the relationship between the North Tropical Atlantic sea surface temperature and Middle East dust activity, researchers can enhance their ability to forecast and anticipate dust events, leading to improved mitigation strategies and preparedness measures. Furthermore, the findings contribute to our overall understanding of global dust dynamics, enabling us to better comprehend and predict the impacts of dust on various regions and ecosystems worldwide.
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