The concept of urban heat islands is well-documented, but recent microclimatic research has shifted focus toward 'cool islands'—specifically, urban parks. While typical asphalt surfaces absorb solar radiation and radiate it as thermal energy, vegetated spaces mitigate this effect through evapotranspiration. During this process, plants absorb liquid water through their roots and release it as water vapor through microscopic leaf pores called stomata. Because this transition from liquid to gas consumes ambient heat energy, it directly lowers the local air temperature. However, the cooling efficiency of a park is not uniform; it is heavily influenced by the canopy density and the specific transpiration rates of the plant species present. Consequently, urban planners cannot simply add any green space to achieve optimal thermal reduction; they must select species whose physiological traits maximize vapor release.
According to the passage, why does the transition of water from a liquid to a gas lower the air temperature in a park?
- It absorbs heat from the surrounding environment.Cevap
- BIt releases thermal energy stored within the plant's roots.
- CIt increases the density of the surrounding forest canopy.
- DIt allows liquid water to escape through the asphalt surfaces.