Characteristics and phenomena of the urban climate

Abstract

The urban climate is a modified boundary layer climate that is directly and indirectly influenced by anthropogenic activity and characterized by phenomena such as urban warming, reduced evapotranspiration, and increased emission of pollutants. As more than half of the global population is urban and the impacts of climate change will increase pressure on cities, a thorough understanding of the urban climate-related processes and phenomena is of vital importance. The present contribution gives a contemporary overview of the characteristics and phenomena of the urban climate addressed to non-specialists in the field. Starting with an analysis of the general differences between large cities and their surrounding environments, important aspects such as the radiation, energy and water balance as well as the temperature distribution in cities are presented in detail. Additionally, the situation of urban air quality and human–biometeorological aspects are described and the impact of climate change are addressed. Finally effective local adaptation and mitigation measures to reduce urban warming and flooding due to heavy rainfall are discussed.