Scientists have found that the Amazon jungle plays an important role in climate regulation, which can cause much earlier than the usual rainy season.
The Amazon rainforest has its own rather strange climatic zone. One of its features is that in the Amazon jungle, rains begin about two to three months before the appearance of humid air currents brought by seasonal winds. However, how is this possible? According to a group of researchers, they managed to find an answer to this question: the trees themselves create rain.
According to the results of previous studies, excess moisture accumulates in the atmosphere over the territory of the Amazon, but scientists have not been able to find the cause of this phenomenon. Satellite data indicate that the increase in water vapor coincided with the greening of tropical forests, resulting in an increase in green foliage. The researchers speculated that excess moisture could be triggered by particles of water that are released during photosynthesis. This phenomenon is called "transpiration", or gas exchange - plants, during respiration, emit water vapor from small pores that are located on the underside of the leaves.
Ron Fu, a climate scientist at the University of California, Los Angeles, suggested that the amount of moisture that is released is probably enough to form low-level clouds over the Amazon. Using the NASA Aura satellite (a spacecraft whose main task is to study the chemical composition of the earth's atmosphere), a study of water vapor in this region was carried out. Typically, the moisture that evaporates from the ocean is lighter than the dense water vapor released into the atmosphere by plants. This is because when moisture evaporates from the ocean, water molecules that contain the heavy hydrogen isotope deuterium remain in the ocean. Plants, on the other hand, absorb water from the soil and release it into the atmosphere without changing the isotopic composition, so the steam is heavier.
The satellite confirmed these assumptions: a high content of deuterium was indeed found in the moisture above the Amazonian forests. As Fu points out, the concentration of deuterium is very high to explain the excess moisture by accidental wind from the ocean. In addition, the highest deuterium concentrations were recorded during the driest periods, when the process of photosynthesis is most intense.
Scientists tried to answer the question: what role is assigned to this in the global climate picture? Clouds induced by trees can work on the domino principle: when it rains from the clouds, the atmosphere overheats, which, in turn, provokes an intensive circulation of air masses. As Fu and her colleagues point out, this could cause a shift in established patterns of air flow, which could lead to an increase in moisture inflow from the ocean. Thus, plants in the rainy season play an important role and, if necessary, are able to independently provoke rainfall.