Glossary

Albedo: Proportion of incoming solar radiation reflected by a surface. The brighter and smoother a surface, the higher is albedo and the more sunlight is relfected.

Anthropogenic heat: Heat generated by human activitiy, including heat resulting from cars, industry and heated buildings.

Convection: Heat transport that occurs when air moves past a warm body and carrying away energy. The faster the air moves and the bigger the temperature difference between air and body, the bigger the windchill effect.

Energy balance: The difference between incoming and outgoing heat of a physical object. Is the balance positive, it will get warmer and vice versa. The energy balance can be looked at on different scales, for example as an energy budget of a whole city or of a single person. 

Evapotranspiration: Total amount of water transferred thorugh evaporation and transpiration by vegetation. Generally refers to the capacity of trees and other plants to absorb heat and avoid heating up the air around it.

Latent heat: Energy that is absorbed through the process of evaporation, which does not result in higher temperatures.

Microclimate: The climate of a small space, which differs from that of the surrounding area. Conditions such as air temperatures, air flow and radiation balance are influenced by the immediate physical surroundings as well as the climate of the surrounding region.

Relative humidity: Percentage of humidity in the air relative to the total amount the air will hold at that temperature. Relative humidity will change with changing temperatures as the air can hold more or less water.

Sensible heat: Heat that results in a temperature change.

Solar radiation: Total amount of energy emitted from the sun, most of its experienced as heat, only some of it is visible as light.

Terrestrial radiation: Energy emitted by our physical surroundings. If the pysical surrundings of a person emits more energy relative to the amount the person is emitting, it will warm up that person.

Thermal Comfort: 

Urban canopy layer: The lowest part of the urban atmosphere which extends fromt he ground to the height of the buildings and trees. The canopy layer is characterized by heterogenity compared the layers above, because conditions on this gorund level vary wildly depending on the immediate surroundings.

Urban canyons: Defining geometry of the urban environment. Defined by its aspect ratio (width & height) or sky view factor, meaning the amount of sky "seen" from a specific point on the gorund. The nature of the urban canyon affects the amount of solar radiation arriving on the street level and how much energy is emitted back into the atmosphere over time i.e. how fast a city cools down. 

Urban heat islands (UHI): Temperature difference between a city and its surrounding rural areas, whereby in the densest part of the city the highest tempereatures can be observed.