Quantifying microclimatic conditions: An attempt to more accurately estimate urban landscape water requirements

The competing demands of landscape irrigation and other urban water requirements are motivating improvements in water efficiency in arid urban areas. Complex urban environments create unique microclimates that can result in different irrigation requirements across the landscape. The microclimate coefficient (K-mc) is applied to adjust evapotranspiration from reference surfaces to local microclimatic conditions. The objectives of this study were to quantify and model urban microclimate conditions across the landscape. Air temperature and relative humidity were recorded at five landscapes with different surrounding land cover/use in the city of Isfahan, Iran, over a period of three years. The results showed that the K-mc values varied both locally and over time. The monthly K-mc at the five sites varied from 0.87 to 1.34. Results indicated that assuming a constant K-mc throughout the year may lead to errors in estimating the water requirement of a landscape. The best regression models developed for predicting the K-mc as a linear function of surface cover types explained 83 % of the variance in the K-mc.