The recently erupted White Island volcano in New Zealand has caused more than 40 casualties. In addition to the short-term damage, large volcanic eruptions can also cause significant climate change for the next two to three years.
"We found that rainfall increased significantly in global arid regions after volcanic eruptions." said ZUO Meng, a doctoral student from the Institute of Atmospheric Physics, Chinese Academy of Sciences, along with her mentors Prof. ZHOU Tianjun and associate Prof. MAN Wenmin. Their findings are recently published in Journal of Geophysical Research: Atmospheres.
Arid regions are defined by regions where the local summer precipitation less than 1 mm per day. Occupying approximately 41% of terrestrial land surfaces, arid regions are home to more than 38% of the world’s population, which are among the most sensitive areas to climate change and natural disasters.
Previous studies have examined the precipitation response in arid regions to human activities, but knowledge of the hydroclimate response to natural external forcing such as volcanic aerosol over arid regions is quite limited.
Zuo analyzed large sets of data and the climate model simulations to investigate the impacts of volcanic eruptions on rainfall over global arid regions. “I think we are the first to give a comprehensive picture of rainfall changes over arid regions after volcanic eruptions, and use a diagnostic method to quantitatively analyze the factors determining rainfall response, which is helpful to understand the different physical processes of volcanoes at different latitudes affecting the rainfall responses”.
The team found that both the proxy and observations show that the arid regions get wetter after different types of volcanic eruptions. They also suggested the underlying mechanism — the changes in atmospheric circulation play a dominant role in rainfall responses. The wetter arid regions are attributed to the enhanced cross equator flow and the monsoon-desert coupling mechanism. They also found that the response of the extreme rainfall is consistent with that of the mean rainfall, but more sensitive on a regional scale, which are related to drought and flood hazards.
"This work has implications on the design of Decadal Climate Prediction Project (DCPP) experiments and the implementation of geoengineering activities”, the corresponding author Prof. ZHOU Tianjun, highlighted.
Zuo, M., Zhou, T. *, & Man, W. (2019). Wetter global arid regions driven by volcanic eruptions. Journal of Geophysical Research: Atmospheres, 124. https://doi.org/10.1029/2019JD031171.
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