Lack of trees and excess concrete: how heat islands make Manaus neighborhoods hotter during the Amazon summer

Sun and heat in Manaus Amazon Network The advance of the driest period of the year in Amazonas, the so-called "Amazonian summer", reveals a striking contrast in temperatures in the daily life of the capital of Amazonas. While wooded areas manage to maintain milder climates, highly urbanized neighborhoods in Manaus face suffocating temperatures due to the heat island phenomenon. ? Heat islands occur when man-made surfaces, such as asphalt, concrete, roofs and bricks, absorb heat from the sun during the day and slowly release it into the environment. The lack of vegetation and paving means that entire blocks accumulate solar radiation, raising the air temperature. Given this scenario, Dr. Luciana Gatti, researcher and coordinator of the Greenhouse Gas Laboratory at the National Institute for Space Research (INPE), warns about the need for urban adaptation. "For our survival, we need less hot cities", highlights the researcher. According to the expert, the explanation for the uneven heating in the city lies in the high level of urbanization and the waterproofing of the soil. The intense concentration of asphalt, concrete and dark roofs makes the urban environment function as a thermal accumulator: these surfaces absorb solar radiation throughout the day and return the energy in the form of heat, preventing neighborhoods from being able to cool down even during the night. ??How do scientists measure 'heat records'? Why does Manaus feel the impact of heat islands so much? Heat on the bus: high temperatures and heat inside public transport in Manaus According to data from the National Institute of Meteorology (Inmet), a combination of climatic and land occupation factors makes Manaus vulnerable to heat accumulation. The geographical location under the equatorial climate already imposes, by nature, high rates of humidity and a high incidence of solar radiation throughout the year. However, it is the transformation of urban space that exacerbates the problem. Soil waterproofing: dense paving over old green areas prevents rainwater from infiltrating. Without water held in the ground to evaporate, the city loses the earth's natural cooling mechanism. Retention in asphalt and concrete: the predominance of dark materials in paving and buildings has a low reflectivity index (albedo). In practice, asphalt and concrete function as 'thermal sponges' that absorb the Sun's energy during the day and release it at night. Barriers to air circulation: the accelerated and often disorderly advancement of constructions and buildings in different neighborhoods creates physical blockages. These barriers prevent the humid breezes blown by the Negro and Amazon rivers from circulating through the city. According to meteorologist Andrea Ramos, the low river levels during the typical Amazonian summer drought, which occurs between July and November, do not directly produce a hot air mass over Manaus. What favors heat is the same atmospheric environment that contributes to drought: less rain, less cloudiness and a greater incidence of solar radiation. When the soil and vegetation lose moisture, solar energy is no longer used to evaporate water and is converted into sensible heat, directly heating the air close to the surface. The current heat must be interpreted mainly by the atmospheric and seasonal pattern", points out Andrea Mendes. Air quality worsens in Manaus this Friday (14); expert points out relationship with fires Rio Negro retreats 52 cm in Manaus, but ebb continues within normality in the Amazon Basin, points out SGB 'Urgent for the public authorities to start reversing this', assesses expert For the INPE researcher, the lack of urban afforestation combined with construction materials transforms cities into hostile and dangerous during extreme heat events. "People don't have very wooded cities and this makes them hotter. It is urgent that the public authorities begin to reverse this because we are going to have more and more heat waves, and they will be more intense", warns Luciana Gatti. The scientist reinforces that structural interventions and simple attitudes in homes can act as immediate allies to alleviate the internal heat of houses: "Painting houses white, including on the roof or especially on the roof, helps to cool because solar energy reflects it. The darker the cement or asphalt, the more heat-absorbing capacity it has. It absorbs radiation and keeps the heat in the house", explains Gatti. Practicing physical activities on days of intense heat constant hydration Disclosure How does the humidity in Manaus worsen the sensation of heat? The impact of heat islands becomes even more critical in Manaus due to the conditions of the equatorial atmosphere. During the Amazonian summer, the reduction of clouds allows long hours of direct sunlight on the asphalt. However, this severe warming occurs in an environment that remains with high relative humidity. Meteorologist Andrea Mendes explains that this combination is the determining factor for the risk to human health in the capital. "In the Amazon summer, there is a reduction in rainfall and cloudiness, which allows for more hours of direct solar radiation and greater surface heating throughout the day. In Manaus, this effect occurs in an environment that remains relatively humid", she explains. She reports that when humidity is high, sweat evaporates less efficiently, reducing the main form of cooling. Thus, a temperature of 36°C or 37°C can produce a thermal sensation significantly greater than the value indicated by the thermometer. Afforestation as a shield: vegetation can reduce temperature by up to 4°C Data from the National Institute of Meteorology (Inmet) indicate that the creation of green corridors and planned afforestation have the capacity to reduce room temperature at around 4°