Microclimate Effects and Irrigation Water Requirement of Mesic, Oasis, and Xeric Landscapes

Urban irrigation is an essential process in land-atmosphere interaction. It is one of the uncertain parameters of the urban hydrology because of the presence of various microclimates. This study investigates the microclimate effects and irrigation water requirements of three landscape types in an arid region of Phoenix, AZ. The microclimate effect encompassed surface temperature, air temperature, and wind speed. The three landscapes include mesic, oasis, and xeric. The simulation was conducted using ENVI-met software for the hottest day of the year (23rd June 2011). The simulated model was validated using ground data. Results show that the mesic landscape induced cooling effects, both in the day-time and nighttime, by reducing the surface temperature and air temperature. However, the mesic landscape showed high-water consumption because of high leaf area density. The oasis landscape showed more day-time cooling than the mesic landscape, but the nighttime warming was similar to the xeric landscape. However, the potential irrigation water requirement was lower than the mesic landscape. Moreover, microclimate conditions varied spatially in each neighborhood. The xeric landscape showed lower wind speeds and air temperatures between the buildings. Overall, the oasis landscape proved to be the most efficient of the three landscapes for water consumption and day-time cooling.