The flying river is a movement of large quantities of

water vapor Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...

transported in the atmosphere from the

Amazon Basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

to other parts of South America. The forest trees release

into the atmosphere through

transpiration Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, c ...

and this moisture is deposited in other localities in the form of

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

, forming a virtual

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

Concept

An average forest tree will release 1000 litres (220 imp gal; 264 US gal) of water vapor into the atmosphere every day. It has been found that whereas every square metre of the surface of the sea evaporates one litre of water each day, the same area of forest evaporates about eight times as much because of the multiple layers of foliage in the

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

of the trees. The main airflow in the Amazon basin is towards the southwest. When this air mass reaches the Andes, the mountain range acts as a "natural barrier", redirecting huge volumes of humid air towards the Amazon regions of Colombia, Ecuador, north and south of Peru, central and southern Brazil as well as towards northern Argentina, Paraguay, and Uruguay, and rain falls in these areas. Some part of this air manages to surmount the

cordillera A cordillera is a chain or network of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly used in physical geogra ...

and deposits rain in the west of Peru. Other air masses travel northwards from the Amazon basin, passing over Colombia, Venezuela, Guyana, French Guiana, and Suriname.

Climatic consequences of deforestation

In 2009 Antonio Nobre, a Brazilian climate scientist, stated that without the flying river, much of southern Brazil, which produces approximately 70% of the country's

GNP The gross national income (GNI), previously known as gross national product (GNP), is the total amount of factor incomes earned by the residents of a country. It is equal to gross domestic product (GDP), plus factor incomes received from n ...

, would be arid desert. Clearing the Amazon forest for logging and agriculture is likely to result in lower yields elsewhere. Smoke from the fires set by some farmers to clear land sends particles into the atmosphere, resulting in diminished precipitation, which in turn leaves the trees, which have evolved in wet conditions, vulnerable to fire. The

drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, ...

in southern Brazil in 2010 is believed to be due to the drying up of the flying rivers, and the even worse 2014-5 drought is also attributed to this.

Flying Rivers Project

With its large surface area and abundant rainfall, Brazil receives more rain in a year (estimated at ) than any other country. In 2007, the Swiss-Brazilian pilot

Gérard Moss Gérard Moss, Member of the Most Excellent Order of the British Empire, MBE (born 16 May 1955, died 16 March 2022) was a Swiss Brazilian, Swiss-Brazilian pilot, engineer, public speaker, environmentalist and explorer born in England. As a pilot, ...

joined with scientists to initiate a project to evaluate the source of the atmospheric water over Brazil and examine the possibility that recent droughts in the country are being caused by the

deforestation of the Amazon rainforest The Amazon rainforest, spanning an area of 3,000,000 km2 (1,200,000 sq mi), is the world's largest rainforest. It encompasses the largest and most biodiverse tropical rainforest on the planet, representing over half of all rainforests. The ...

. This is the Flying Rivers Project. The primary objective of the project is to "try to ascertain the origin of the water vapour, rainwater and river water in the areas crossed by the flying rivers". Other objectives are to scientifically evaluate the processes involved in this water transfer and to educate the public in understanding the importance of the Amazon rainforest as a source of the water that is vital for their lives and the economy.

References

{{reflist Physical geography Amazon basin Precipitation Climate forcing Environmental issues with water