Eruptions may have an effect on rainfall
Source: Agencies |
November 6, 2010, Saturday
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Print Edition
Print Edition
SCIENTISTS studying tree rings to reconstruct the past have found that major volcanic eruptions can boost rains in Southeast Asia, challenging a common perception of volcanoes as purely destructive forces.
Studies in the past have shown massive eruptions such as the 1815 Tambora blast, and Krakatau in 1883, both in Indonesia, dimmed temperatures globally and wiped out crops.
Researchers at Columbia University's Lamont-Doherty Earth Observatory in the United States wanted to study the impacts on the Asian monsoon, whose rains are vital to crops and livelihoods for billions of people.
The only way to figure this out was to go back in time. They studied the growth rings from centuries-old trees from about 300 sites across Asia, in a study published in the online edition of the journal Geophysical Research Letters.
They studied the impacts on rainfall from 54 major eruptions going back 800 years by measuring how this affected trees' growth. Narrow, thin growth rings show low rainfall and the opposite for good rains.
The tree rings showed that huge areas of southern China, Mongolia and the surrounding region consistently dried up in the year or two following big volcanic blasts, while mainland Southeast Asia received more rain.
Explosive eruptions send up sulphur compounds that turn into tiny sulfate particles high in the atmosphere, deflecting some of the sun's energy. The cooling of temperatures at ground level can last for months or years.
The release of the research comes during the series of violent eruptions of Indonesia's Mount Merapi.
These current eruptions, though large, do not yet appear to have the potential to affect global temperatures, a press release accompanying the study said.
Studies in the past have shown massive eruptions such as the 1815 Tambora blast, and Krakatau in 1883, both in Indonesia, dimmed temperatures globally and wiped out crops.
Researchers at Columbia University's Lamont-Doherty Earth Observatory in the United States wanted to study the impacts on the Asian monsoon, whose rains are vital to crops and livelihoods for billions of people.
The only way to figure this out was to go back in time. They studied the growth rings from centuries-old trees from about 300 sites across Asia, in a study published in the online edition of the journal Geophysical Research Letters.
They studied the impacts on rainfall from 54 major eruptions going back 800 years by measuring how this affected trees' growth. Narrow, thin growth rings show low rainfall and the opposite for good rains.
The tree rings showed that huge areas of southern China, Mongolia and the surrounding region consistently dried up in the year or two following big volcanic blasts, while mainland Southeast Asia received more rain.
Explosive eruptions send up sulphur compounds that turn into tiny sulfate particles high in the atmosphere, deflecting some of the sun's energy. The cooling of temperatures at ground level can last for months or years.
The release of the research comes during the series of violent eruptions of Indonesia's Mount Merapi.
These current eruptions, though large, do not yet appear to have the potential to affect global temperatures, a press release accompanying the study said.
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