Oasis effect
From Wikipedia, the free encyclopedia
The oasis effect refers to the creation of a local microclimate that is cooler than the surrounding dry area due to evaporation or evapotranspiration of a water source or plant life and higher albedo of plant life than bare ground.[1] The oasis effect is so-named because it occurs in desert oases.[2] Urban planners can design a city's layout to optimize the oasis effect to combat the urban heat island effect.[3] Since it depends on evaporation, the oasis effect differs by season.[1][2]
An oasis contains moisture from a water source and/or plants. When that water evaporates or transpirates, heat from the surroundings is used to convert liquid to gas in an endothermic process, which results in cooler local temperatures.[4] Moreover, vegetation has a higher albedo than bare ground, and reflects more sunlight, leading to lower land temperatures, lower air temperatures, and a cooler local microclimate.
Seasonal effects
The oasis effect occurs most prominently during the summer because warmer temperatures lead to more evaporation.[1] In the winter, the oasis effect operates differently. Instead of making the oasis cooler, the oasis effect makes it warmer at night. This occurs through the fact that trees block heat from leaving the land. Basically, radiation cannot be emitted back into the atmosphere because the trees intercept and absorb it.[2]
