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Technique can help predict droughts in Brazil

An article published in Geophysical Research Letters indicates that the surface temperature of the North Atlantic Ocean can help predict extreme weather events in northeast Brazil up to three months in advance.

The study showed, based on the concept of precipitation deficit (less amount of rain), that in recent years the northeast of the country has received more influence from the North Atlantic than from the tropical Pacific, which, until then, was considered one of the main drought intensifiers in the region.

At the same time, scientists have noticed that atmospheric linkages between the Pacific and the North Atlantic have become more frequent, a situation that could reinforce the droughts that have occurred in the region in recent decades.

The research also considered that land use changes influence this scenario, as they can lead to changes in the hydrological cycle, as modeling studies have already demonstrated, particularly with regard to the Amazon basin. For this reason, the scientists suggest that further research be conducted using the methodology developed to study how changes in land management alter climate patterns and interactions.

In a statement granted to the FAPESP agency, the scientist of the National Institute for Space Research (INPE) and co-author of the article, Lincoln Muniz Alvez, said that “the study was motivated by the severe drought which lasted from 2012 to 2015 This long period led me to reflect, from a meteorological point of view, on the influence of the temperatures of the tropical oceans on the climate. The difference now is the innovative methodology that explores the contrasts between the Pacific and the Atlantic, and the drought pattern in northeast Brazil”.

The drought cited by the researcher was so intense that it destroyed crops in the region and left towns and villages without water.

Other studies had previously suggested that the lack of rain was exacerbated by the high surface temperature of the Atlantic Ocean and the onset of the El Niño weather phenomenon, which occurs when temperatures in the Pacific Ocean are above normal.

In Brazil, the effects of El Niño included intense drought in the northeast and Amazon, a much longer than normal dry season in the north and in several parts of central Brazil (regions north of the states of Minas Gerais and Goiás, as well as in the Federal District), and floods in the South. This phenomenon has already caused losses in different parts of the world.

Alves assures that “based on our multifaceted analysis, the paper provides ample evidence allowing meteorologists to monitor signals from the tropical Atlantic several months in advance. The influence of the Pacific is undeniable, but the Atlantic has more.

How was the article made?

To arrive at these results, researchers from Brazil, China, Australia and Germany sought to understand the relationships between sea surface temperature variability and the standard precipitation index, which were interpreted as direct interactions, and the relationships between the oceans, which have been interpreted as indirect. effects on precipitation levels.

Additionally, precipitation data from the Climate Prediction Center (CPC), a branch of the US National Oceanic & Atmospheric Administration, National Weather Service (NOAA-NWS) was used.

To check the consistency of the data obtained, they compared the results with Niño 4, an area that includes the central equatorial Pacific and part of the South Atlantic. The rainy season was defined as January-April and the dry season as May-August.

According to Alves, “several other studies have corroborated our findings.” The researcher also points out that other factors must be taken into account. “When we talk about climate change, we also talk about the socio-economic impacts and the effect on biodiversity. “Meteorological centers can use the model to work on prevention as an input to public policy and decision-making on mitigating extreme events,” he said.


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