The impact of screening on road surface temperature

The effect of screening on road surface temperatures is analyzed using data from the Swedish road weather information system (RWIS) together with data from thermal mapping The study deals with the analysis of temperature vari ations caused by shading Of the road surface during clear daytime condition s and focuses on the relation between solar elevation and magnitude of road surface temperature differences between screened and sun-exposed areas. Al so included is an analysis of how the temperature differences during the da y affect rhc establishment of temperature variations after sunset and the t ime it takes after sunset for temperature differences caused by shading to decline. The results show that the magnitude of road surface temperature di fferences between sun exposed and screened sites (RSTdiff) that develop dur ing clear day conditions can be attributed to solar elevation (beta) and ca n be expressed by the equation: RSTdiff =-2.7+0.46(beta). A relationship be tween the daily, maximum temperature difference and the preservation of the screening effect after sunset is observed. The effect after sunset can be described by: RSTdiff= A-B h+C h(2)-D h(3)-E h(4)+F h(5), where h is the ti me in hours after sunset and A to F are constants related to the time of th e year at the actual sire.