A team of reseachers working in the US and Europe has constructed a model that maps areas most at risk to flooding due to El Niño and La Niña weather aberrations. The team published their paper in the Proceedings of the National Academy of Sciences (PNAS) on October 27.
Once perfected, this model would be of significant use to the Philippines, which had been battered by the El Niño and La Niña weather events for a long time.
Floods can cause substantial damage to agriculture and may even ruin rural infrastructure crucial to food production. The small team of researchers from the US and Europe describes how they compared weather data from 1959 to 2000 and determined the economic impacts of the floods to create the model that may predict when flooding would occur.
El Niño comes when the warm water west of South America causes more rain to fall in many nations, while La Niña happens when the same waters are cooler than normal, affecting changes to rain patterns.
The impact of both weather patterns differs in many nations, with tropical countries being hit more, with less flooding affecting developed nations.
“Oftentimes the flooding that occurs results in damage to property and loss of life, thus, it would be a good thing if forecasts could be made, warning people in areas most at risk,” Bob Yirka said as he discussed the model online.
“Unfortunately, up till now, such forecasts have not been available because such events don’t always cause the same types of flooding, in the same places,” he added.
The team used the weather data from 1959 to 2000 and zeroed in on the periods when the El Niño and La Niña weather events struck and compared the reports of damage due to flooding. By comparing the results with flood reports during normal times, the researchers were able to craft a model.
The model showed that during El Niño events, 34 percent of the Earth’s surface had higher or lower than normal amounts of flooding, but the number jumped to 38 percent for La Niña weather events.
“The El Niño-Southern Oscillation is known to influence surface temperatures worldwide.
El Niño conditions are thought to lead to anomalously warm global average surface temperature, absent other forces,” researchers Sandra Banholzer and Simon Donner said. They added that recent research has identified distinct possible types of El Niño events based on the location of peak sea surface temperature anomalies.
“Here we analyze the relationship between the type of El Niño event and the global surface average temperature anomaly, using three historical temperature data sets,” they said.
“Separating El Niño events into types reveals that the global average surface temperatures are anomalously warm during and after traditional eastern Pacific El Niño events, but not central Pacific or mixed events,” they noted. “Historical analysis indicated that slowdowns in the rate of global surface warming since the late 1800s may be related to decadal variability in the frequency of different types of El Niño events.”