Study Finds Rainfall in Arid Regions Increases After Volcanic Eruptions

The White Island volcano in New Zealand erupted recently, resulting in over 40 casualties. Apart from the temporary damage, huge volcanic eruptions could also lead to considerable changes in the climate within the next two to three years.

We found that rainfall increased significantly in global arid regions after volcanic eruptions.

ZUO Meng, Doctoral Student, Institute of Atmospheric Physics, Chinese Academy of Sciences

A research work carried out by ZUO and her mentors, Professor ZHOU Tianjun and Associate Professor MAN Wenmin, was recently reported in the Journal of Geophysical Research: Atmospheres.

Arid regions are areas where the local summer precipitation is below 1 mm per day. These regions occupy around 41% of terrestrial land surfaces and are inhabited by more than 38% of the world’s population. Arid regions are one of the most sensitive to natural disasters and climate change.

Earlier research works have investigated the precipitation response in arid regions to human activities. However, understanding of the hydroclimatic response to natural external forces like volcanic aerosol over the arid areas is highly restricted.

ZUO examined the climate model simulations and huge sets of data to examine the effects of volcanic eruptions on rainfall over global arid areas.

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.

ZUO Meng, Doctoral Student, Institute of Atmospheric Physics, Chinese Academy of Sciences

From both the observations and proxy, it was found that the arid regions became wetter after various types of volcanic outbursts. Therefore, the scientists proposed that the fundamental mechanism, which is the variations in atmospheric circulation, has a crucial role to play in rainfall responses.

It was proposed that the monsoon-desert coupling mechanism and the improved cross equator flow were caused by the wetter arid regions. The response of very high rainfall was found to be consistent with that of the mean rainfall. However, on a regional scale, it was found to be quite sensitive. These were attributed to flood hazards and drought.

This work has implications on the design of Decadal Climate Prediction Project (DCPP) experiments and the implementation of geoengineering activities.

ZHOU Tianjun, Study Corresponding Author, Institute of Atmospheric Physics, Chinese Academy of Sciences

Source: http://english.cas.cn/