WHAT ARE FLYING RIVERS? 

Flying Rivers are air currents that carry water vapour from Amazonia in a southerly direction as far as Northern Argentina. 

The humidity brought by these “airborne rivers” is responsible for a large part of the rain that falls in the Centre-west, Southeast and South of Brazil.

The Flying Rivers project, which commenced in March 2007, is attempting to quantify the amount of water vapour transported by these invisible rivers that flow right over our heads. They may well account for a volume of water that is on a par with discharge of the mighty Amazon River itself. Estimated at 200,000 cubic metres per second, the Amazon is responsible for an astounding 20% of all continental run-off in the world.

The lower half of Brazil, essentially its agricultural and industrial heartland, depends entirely on its hereto reliable and abundant rainfall. Brazil receives more rain that any other country in the world (estimated at over 15,000 cubic kilometers per year – almost double the next best, Russia) and has, until recently, relied on hydro power for up to 90% of its energy requirements.

In the face of uncertainty about the ultimate impact of global warming, the search is on for further explanations and new data. By following the same westerly direction as the trade winds from the Amazon delta to the westernmost borders of Brazil and collecting samples of airborne water vapour, it is hoped to establish the percentage of humidity that is returned to the atmosphere by evapotranspiration from the rainforest. In parallel, the aim is to demonstrate to the Brazilian people as a whole the importance of maintaining the rainforest alive and well, so that the whole process may continue indefinitely.

The Flying Rivers project was devised by Gérard Moss, who undertakes all the active flying and collecting of samples. The analyses of these samples, interpretation of the results and final conclusions are in the capable hands of a renowned team of Brazilian scientists, spearheaded by the eminent Prof. Eneas Salati.

IS IT POSSIBLE THAT THE SOUTHEAST OF BRAZIL COULD ONE DAY BECOME A DESERT?

If we carefully examine a map of the southern hemisphere, it soon becomes apparent that landmasses between the 20th and 30th parallels are largely covered by deserts… Namib, Kalahari, southern Madagascar, Great Sandy and most of Australia, Atacama, going eastbound. When we cross the Andes, however, we come to the vast green lushness of Paraguay, Brazil and Northern Argentina. So how come?

It is a complex question and there is no easy answer, but part of the response lies in Amazonia, in the moisture-laden trade winds that initially bring humidity off the ocean to the mouth of the giant river, carry it across the continent in an on-going process of rainfall/evapotranspiration/rainfall until hitting the wall of the Andes. The Cordillera forces the winds downwards, so they continue to carry this very same moisture in a southerly direction, greening the continent.

So what might happen in the south if the rainforest is ultimately destroyed to make way for pasture, soya and sugarcane? If the hydrological cycle stops continually pumping out humidity and sending it south in umpteen powerful aerial rivers?

That is the question!

OBJECTIVES

• To try to ascertain the origin of the water vapour, rainwater and river water in the areas crossed by the flying rivers.
• Through the results obtained from the analyses of the samples collected, further a better scientific understanding of these processes and their importance in collective rainfall patterns in central and southern Brazil.
• To help Brazil’s large urban population – the man in the street – understand the importance of protecting the true source of the water resources upon which they depend for drinking, domestic and industrial usage, energy and agriculture.
• To raise awareness of the key rôle played by the Amazon rainforest in generating the water that turns the great powerhouse of Brazil’s economic activities, and put a value on its preservation.

The term “Rios Voadores” or Flying Rivers was coined by Dr. José Marengo to describe the low level jets or air currents that carry water vapour down the eastern flank of the Andes, from Amazonia to Northern Argentina. In this project, the expression is being used in a broader sense to include the complete movement of water vapour from that region towards Southern Brazil.

Find out and see more on the project website (mostly in Portuguese) Rios Voadores