Nocturnal cooling in Local Climate Zone: Statistical approach using mobile measurements

Abstract

Up-to-date climate scenarios warn that the frequency and intensity of heat waves are likely to increase in Europe during the twenty first century. In these circumstances, urban climate is progressively taken into account in urban planning processes, for instance using terrain classifications. The developed methodology involves the Local Climate Zone scheme (LCZ), which has been applied to Nancy, France. Mobile measurements campaigns have been performed using an instrumented vehicle in order to record daily air temperature dynamics, with a focus on the daily cooling period. So as to quantify LCZ cooling before and after sunset over several days, a climatic indicator called Normalized Cooling Rate (NCR) has been used. This study presents statistical regressions that have been performed between normalized cooling rate values calculated from field measurements and urban indicators. Results indicate that normalized cooling rates and most of the studied urban features are correlated. Regression model using sky view factor and distance to the city center seems enough accurate to estimate nocturnal cooling at the district scale.