Ocean currents could help predict forest fires

Monday 14th Nov 2011 by theWeather Club

Tiny temperature changes on the Atlantic and Pacific oceans provide an excellent way to forecast wildfires in South American rain-forests, according to a paper published by University of California, Irvine (UCI) and other researchers funded by NASA. “It enables us three to five months in advance to predict the severity of the fire season," said UCI assistant project scientist Yang Chen.

The team found there was a correlation between El Niño patterns in the Pacific and fire activity in the eastern Amazon. Writing in the journal Science, they say they also found a link between Atlantic Sea Surface Temperatures (SST) changes and fires in southern areas of South America.

In the paper Forecasting Fire Season Severity in South America Using Sea Surface Temperature Anomalies, the team suggest that the data could be used to help produce forecasts of forthcoming fire seasons. "We found that the Oceanic Niño Index (ONI) was correlated with inter-annual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation (AMO) index was more closely linked with fires in the southern and south-western Amazon," they wrote.

The ONI is a system used to identify El Niño (warm) and La Niña (cool) events in the Pacific Ocean, while the AMO Index performs a similar function in the Atlantic. "Combining these two indices, we developed an empirical model to forecast regional fire severity with lead times of three to five months," the team’s paper explained. "Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires."

Previous studies have shown high-fire years in South America are generally associated with an extended dry season and low levels of rainfall. It has also been shown that variations in precipitation levels in the Amazon are regulated by SSTs in the Atlantic and Pacific oceans. "The most severe droughts observed in the Amazon over the past three decades have occurred when the tropical eastern Pacific and North Atlantic were anomalously warm," Dr. Cheng’s team wrote.

The existence of an early warning system would be of real benefit as it would allow for a more pro-active and efficient system of drought management. "Managing fires to conserve biodiversity and carbon stocks in forest and savannah ecosystems requires advance planning on multiple timescales," the report read. These include the “design of policy mechanisms that modify long-term development, as well as improved use of short-term meteorological forecasts of fire behaviour during years with high fire season severity," it continued.

There is a long way still to go before these findings can be used to improve things on the ground. However it is another example of the interconnectedness of the world’s environmental systems, and an incentive to continue to their study, even in these very difficult times.