Jörgen Bogren
Universitetslektor
Institutionen förOm Jörgen Bogren
Research
Forecasting temperature variations One important area is to forecast the occurrence of temperature variations along stretches of road. To be able to forecast these variations focus is set on the relationship between topography, weather and temperature variations. A study dealing with the temperature development in undulating terrain is presented in Gustavsson, Karlsson, Bogren & Lindqvist - "Development of temperature patterns during nocturnal cooling". Studies have been carried out to be able to give a mathematical description of the connection between topography and temperature. Integration of meso scale weather forecasts with the LCM is another part that is under development.
For detailed local temperature forecasts the screening effect is crucial. The variation in temperature differences between screened and exposed sites during day and season are analysed are to be presented in "The impact of screening on road surface temperature" - Bogren, Karlsson & Gustavsson.
Physical processes - slipperiness Detailed measurements of climatological parameters in close connection to the road surface give the background for analysis of the processes that are important for formation of slipperiness during different weather conditions. Accurate instruments are used and placed at different levels above and below the road surface for coverage of the relative importance of temperature, humidity and wind. As a compliment IR-recordings are used for detailed measurements of the road surface temperature. The paper "The applicability of similarity theory to a road surface" Chen, Gustavsson & Bogren, presents a part of this project. This part will be followed by a paper describing the heat flow in the ground and how this information can be used to perform better forecasts of the surface temperature - "Variation of the thermal diffusivity of a road bed related to non-conductive processes".
Modelling of climate - Projecting of new roads The research in this part is aims at adapting the local climatological model at the projecting stage of different applications where topoclimate is important to consider. By this adaptation it is possible to calculate the local variation in temperature associated with different elements in the landscape. When planning new roads it is possible to use this knowledge as a tool for comparing different alternatives of routes with respect of risk of slipperiness. The LCM is used together with a geographical information system and temperature variations are calculated for different areas in respect of weather conditions. Statistical information about meteorological conditions is obtained from synoptic weather stations and integrated in the analyse. A study from an area on the Swedish west coast is presented in the paper "GIS as a tool for planning new roads in respect of climatological factors" and a further application will be in connection with calculation of indices for classification of winter climate.
Topoclimate The topoclimatological research focuses on the nocturnal cooling and development of temperature variations in complex terrain. Two approaches are used modelling of temperature development and extensive field measurements of the existing temperature pattern. The modelling part aims at determining the relative importance of cold air drainage in valleys regarding the establishment of temperature variations. The measurements on the other hand aims at detecting and analysing the processes acting in different environments. By combining these two parts it will be possible to link the processes acting in different scales and environments and their relative influence on temperature variations.
Current projects The road climatology group works together with several national and international partners. These projects have a focus on solutions for detecting and giving warnings about severe weather conditions along roads. Cooperation is made both with authorities, companies and universities. Please have a look at following links for further information:
www.roadidea.eu www.sris.nu www.bifi.nu http://cdu.infra.kth.set