Content

Surface Temperatures Day and Night

Summary

Large cities are particularly susceptible to climate change. In densely built-up areas, natural landscapes are often displaced by stone and concrete. A variety of measuring processes are used and evaluated to mitigate any undesirable changes to the urban climate, also supporting urban and landscape planning.

Satellite data may be used to record a large area almost all at once. Systems equipped with thermal-infrared (IR) imaging technology are used to record the temperatures of individual surface elements such as roofs, streets and tree crowns. In this process, the landscape is scanned from a great height. This type of measurement is based on the physical principle that all objects emit heat radiation according to their surface temperatures: during the day, the short wave radiation spectrum is what counts; it mainly indicates the direct radiation of solar energy, its absorption and reflection. At night, it is exclusively the long wave spectrum along with the soil heat flux that influence an object’s heat radiation.

The satellite passes over the Berlin region approximately every 14 days, in the evening and the morning of the following day. Therefore, images for the respective day and night surface temperatures were analysed. Built-up areas such as the city centre displayed high temperatures. Extensive farmland and fields located outside the city turned out to be the coldest areas.

Are you interested in learning how surface temperatures developed until the year 2000? Access our work results and maps here.