Adjustment time for road surface temperature during weather changes

Abstract

The object of this study is to examine the possibility of developing a model that can determine road surface adjustment times to new conditions after weather changes. Situations where the weather changes from clear to overcast conditions are studied in order to produce a worst‐case scenario. One hypothesis tested is that the decrease in road surface temperature (RST) differences between shaded and sun‐exposed stations on clear days can be used to determine the reduction in RST difference on days with weather changes. A relationship that describes the variation in RST difference as a function of time of day and season is developed. For clear days a fourth‐order polynomial can describe the relationship between RST differences and time of day. The coefficient in the polynomial depends on maximal solar elevation. Validation of the model for clear days showed that the deviation between modelled and measured values varied between 0.3 and $0.5\ ^{\circ}\hbox{C}$. It was also possible to use the clear day relationship to predict the decrease in RST differences for situations with weather changes, but during these situations the deviations between modelled and measured values were higher and also tended to show a positive bias. Copyright © 2001 Royal Meteorological Society

Modeling Road Surface Temperature from Air Temperature and Geographical Parameters—Implication for the Application of Floating Car Data in a Road Weather Forecast Model

“…However, this study shows that, for thermal-mapping measurements recorded under overcast weather conditions, especially close to or after sunset, the influence of the screening effect over a longer period, up to 12 h, should be considered. This is in accordance with findings from Postgard (2001), which stated that it can take up to eight hours for the RST difference between sun-exposed sites and shaded sites, produced during clear day conditions, to react to overcast conditions. In addition, Bogren et al (2000) indicated that the daytime RST difference caused by screening effects can remain up to four hours after sunset in early spring.…”