Every body, sentient or inanimate, with a temperature above 0 Kelvin radiates proportionally to the fourth power of its surface temperature, its emissivity and the Bolzmann constant. The electromagnetic radiation emitted by plants, earth and stones is slightly longer than that of visible light and is therefore below the perception threshold of the human eye. With an array of bolometers, the spatially highly resolved radiation emitted by roof materials and substrates is converted to digital numbers and revealed as digital photographs. We see changing heat capacities and emissivities, the climatic work of the photosynthetic apparatus of plants and microclimatic phaenomena taking place after sunset on a green roof.
Heidi Trimmel, * 1982 Vienna, Austria. Studies in physics, landscape ecology and digital art were followed by a research stays at Météo-France and the Norsk institutt for luftforskning. After her PhD graduation in meteorology she presently engages in environmental physics at the University of Natural Resources and Life Sciences, Vienna.