Analysis of long-wave radiation from urban facets derived from time-sequential thermography (TST) and 3D city model

The surface of urban areas has complex three-dimensional (3D) structure, which creates strong micro-climatic contrasts of temperature. A new topic is the observation of the temporal processes in the transport of radiation and energy. Therefore, a fixed ground based oblique viewing thermal camera system is used to obtain time-sequential thermography (TST) data series of a test side in Berlin, Germany. The TST dataset is combined with a 3-D surface model of the building inventory. Through the navigation of the 3D Model into the viewing perspective of the thermal camera system, every angle within the system sun-target-sensor can be computed. Long-wave radiation flux from different roof facets of buildings are subjects of interest. The azimuth and zenith angles of the roof facets results in shifts in the temporal variation of long-wave radiation flux of these surfaces. The ability to absorb thermal radiation into the roof layer may give information about roof insulation. The study shows that the combination of TST and 3D city models offers new possibilities to analyze thermal characteristics of single building elements. Key words: urban facet, photogrammetric computation, thermo-physical properties 1