The impact of rapid urbanization on pan evaporation in phoenix. Arizona

Rapid urbanization in Phoenix, Arizona over the past few decades has been associated with large increases in local temperature and wind speed values, and decreases in local dew point and relative humidity levels. In this study, the impact of these urban‐induced climatic changes on long‐term pan evaporation rates is identified. The results indicate an increase from 1917 to 1985 in the local pan evaporation in all months of the year. Following a long period of generally increasing pan evaporation levels, a sharp jump in the pan measurements occurred in the late 1960s. This pronounced discontinuity in the long‐term record appears to be associated with the construction of a nearby regional shopping centre in 1968. Given widespread similar land‐use changes throughout this rapidly growing desert city, and given the well‐documented changes in local climatic conditions, potential evapotranspiration increases are probably occurring throughout much of the metropolitan area.