Diurnal variability of hydrological variables in urban areas

Abstract

Urbanization modifies the hydrologic response of a catchment significantly. An understanding of historical patterns and changes in trends of hydrological variables in cities is important to design, maintain and operate the urban infrastructure. The historical trend analysis of various climate variables including temperature and precipitation, and the dependence of precipitation on temperature is presented for six major urban cities in the United States and one city in India. It is noted that there is a common phenomenon of increasing average temperature and decreasing diurnal temperature in all the cities considered. However, variations in precipitation at different durations are not the same. Also, short-duration precipitation events in the recent past are much higher compared to that of long-duration events. Precipitation depths have increased considerably throughout the day in the recent past, specifically in the evenings. Findings indicate that changes in the short-duration precipitation and temperature are prominent in the recent past.