The flying rivers

"Flying Rivers" are a phenomenon discovered above the treetops of the Amazon rainforest where water vapor flows in narrow bands extending several thousand kilometers across the sky. The term was coined by Peruvian climatologist José Marengo and is also known as "atmospheric rivers." These flying rivers are made up of moisture-laden air currents that primarily originate from trade winds from the Atlantic and are joined in the summer by another sub-tropical current. These currents float across the Amazon, encounter the Andes, and then are directed south in a "jet" of speed dropping most of its moisture along the way.
These flying rivers play a crucial role in the regulation of the global climate, and their discovery shed a whole new light on the Amazon rainforest. The Amazon rainforest is known as the "green lung" of the planet because of the hundreds of billions of trees that absorb enormous quantities of carbon dioxide while producing valuable oxygen. The trees in the rainforest also pump water from the ground to the atmosphere, making them "real climate makers," according to earth scientist António Nobre from Brazil's National Institute for Space Research.
However, continuing deforestation threatens the Amazon rainforest and its role in limiting global warming by absorbing carbon dioxide. Scientists have observed and analyzed the rainforest for decades, and the discovery of the flying rivers shows how vital the rainforest is to the regulation of the planet's climate.
The trees play an incredible role in the water cycle and in maintaining the climate in the Amazon region. The sheer quantities of water that evaporate from the forest's three-dimensional structure are a relatively recent discovery, and that this transpiration is made possible by the structure of the trees themselves. One tree occupies one square meter of ground at the base of its trunk, but if you add up all the leaves on the upper part of the tree, it's more than 150 square meters. This means that a hectare of forest is more efficient at evaporating water into the air than a hectare of ocean. It is estimated that 20 billion tons of water transpires every day from the Amazon rainforest to form these flying rivers, a full 3 billion tons more than the amount of water that the mighty Amazon river dumps into the Atlantic.
The Trade Winds usually flow from both hemispheres towards the equator, but they never cross the equator, except for the big South American hydrological portal from Maranhão all the way to French Guyana. This means that the Trade Winds cross unceremoniously into the Amazon and go all the way to Argentina. This is a puzzle for researchers.
Another mystery is the reversal of wind direction between the Atlantic Ocean and the Amazon. Traditionally, meteorologists have understood that a hot surface has low pressure and a cold surface has high pressure, and that the wind always blows from high pressure to low pressure. However, in the case of the Amazon, the wind blows from the Atlantic, which is most of the time hotter than the Amazon, which is most of the time colder. This goes against traditional meteorology and is another puzzle for researchers.
THE BIOTIC PUMP
The biotic pump theory suggests that forests play a crucial role in regulating atmospheric circulation and generating winds. This is because trees transpire vast amounts of water vapor into the atmosphere through their leaves, which then condenses into droplets and forms clouds. As these clouds gather together, they create a fall in air pressure, causing moist air from nearby areas with higher pressure to move towards the forest. This process is what generates and regulates winds, and draws moist air masses inland from the ocean.
The biotic pump theory has important implications for our understanding of global climate patterns. It explains why and how winds blow in from the ocean towards the Amazon rainforest, where they cross the equator and feed the flying rivers. It also suggests that all large natural forests act as biotic pumps, not just the Amazon. This includes equatorial forests in Africa, unique forests in Papua New Guinea, boreal forests in North America, and the exceptional forest belt in Russia that transports moist air from three oceans inland and has a decisive influence on the atmospheric circulation above the entire Eurasian continent.
The discovery of the biotic pump has highlighted the crucial role that forests play in regulating our climate on all continents. It is a mechanism that has the capacity to keep continents moist with humidity, and if it were to disappear for any reason, all freshwater on the continent would drain entirely into the ocean in less than ten years.
Furthermore, recent research has shown that aerosols released into the air by trees, such as those found in the Amazon rainforest, are involved in the generation of water droplets and contribute to the forest's own precipitation. This discovery further highlights the complex and interconnected relationship between forests and the wider environment, and the importance of preserving these ecosystems.
The Amazon rainforest produces an enormous amount of moisture that is transported through the atmosphere to other regions, forming the so-called "flying rivers." These flying rivers are essential for the climate and the well-being of South America, as they bring precipitation to the region and support agricultural productivity.
However, the flow of water from the Amazon in the air is decreasing, and the flying rivers are getting weaker and weaker. This is due to deforestation, which reduces the capacity of the forest to produce moisture and impacts the hydrological cycle. Large-scale reforestation efforts may help to reverse this trend, but it will take a long time for the forest to recover its full capacity.The importance of the biotic pump can hardly be over emphasized. Pristine forest cannot be easily substituted, and even native forests take a long time to recover their full capacity.
In summary, the Amazon rainforest plays an important role in the hydrological cycle and its impact on the global climate. The concept of "flying rivers" - atmospheric rivers that transport moisture from the Amazon to other parts of South America, and the role played by trees in the hydrological cycle are critical to the health of the ecosystem. The danger of deforestation and the negative impact it can have on the hydrological cycle can hardly be overstated.
THE SUNDARBANS AND BANGLADESH
While forests cover 31 percent of the global land area, according to the United Nations Food and Agriculture Organization (FAO), 11.1 per cent of Bangladesh is forested, and the Sundarbans represent close to half of that.
The Sundarbans is the largest mangrove forest in the world and is home to many endangered species of flora and fauna. The Sundarbans plays an important role in climate change for Bangladesh as it acts as a natural barrier against cyclones and storm surges that are becoming more frequent due to climate change. The Sundarbans helps to regulate the local climate by absorbing carbon dioxide from the atmosphere and releasing oxygen through photosynthesis. It is also an important source of livelihood for many people in Bangladesh who depend on fishing and forestry for their income. The Sundarbans plays a crucial role in the water cycle as it helps to regulate the flow of water from the rivers into the Bay of Bengal. The mangroves absorb excess water during monsoon season and release it slowly during dry periods, helping to prevent flooding and droughts. Given the enormous importance of forests in maintaining our ecological balance, we must protect our forests everywhere!

The author is the Managing Director of Engineering Resources International (ERI) - a Sustainable Development Engineering company.
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