Urban climatology
Encyclopedia
Urban Climatology refers to a specific branch of climatology
, it is the branch of climatology concerned with the interactions between urban
areas and the atmosphere
; the impacts they have on one another; and examines these processes (and responses) at various scales see also: urban climate
is considered the father-figure of urban climatology based on his book The Climate of London, which contained continuous daily observations from 1801 to 1841 of wind direction, atmospheric pressure, maximum temperature, and rainfall .
Urban climatology has gained much momentum in recent centuries based on global industrialization and more importantly, urbanization
. The process of urbanization changes the physical surroundings and induces alterations in the energy, moisture, and motion regime near the surface. Most of these alterations may be traced to causal factors such as air pollution; anthropogenic heat; surface waterproofing; thermal properties of the surface materials; and morphology of the surface and its specific three-dimensional geometry—building spacing, height, orientation, vegetative layering, and the overall dimensions and geography of these elements. Other factors that must be considered are relief, nearness to water bodies, size of the city, population density, and land-use distributions .
A number of energy processes are altered to create warming, and various features lead to those alterations. City size, the morphology of the city, land-use configuration, and the geographic setting (such as relief, elevation, and regional climate) dictate the intensity of the heat island, its geographic extent, its orientation, and its persistence through time . Individual causes for heat island formation are related to city geometry, air pollution, surface materials, and anthropogenic heat emission. There are two atmosphere layers in an urban environment, besides the planetary boundary layer outside and extending well above the city: (1) The urban boundary layer is due to the spatially integrated heat and moisture exchanges between the city and its overlying air. (2) The surface of the city corresponds to the level of the urban canopy layer. Fluxes across this plane comprise those from individual units, such as roofs, canyon tops, trees, lawns, and roads, integrated over larger land-use divisions (for example, suburbs). The urban heat island effect has been a major focus of urban climatological studies, and in general the effect the urban environment has on local meteorological
conditions.
Other Research within the field is focused on Air quality, Radiation Fluxes
, Micro-Climates and even issues traditionally associated with architectural design and engineering, such as Wind Engineering
.
Furthermore globally, cities are said to grow into the 21st century (and beyond) due to the opportunities they present and as a consequence of globalization - as they grow and develop the landscapes in which they inhabit will change so too will the atmoshpere resting above them, increasing emissions of GHG's thus contributing to the global green house effect.
Finally, many cities are vulnerable to the projected consequences of climate change (sea level rise, changes in temperature , precipitation, storm frequency) as most develop on or near coast-lines, nearly all produce distinct urban heat islands and atmospheric pollution: as areas in which there is concentrated human habitation these effects potentially will have the largest and most dramatic impact (e.g. France's heat wave in 2003) and thus are a major focus for urban climatology..
Climatology
Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences...
, it is the branch of climatology concerned with the interactions between urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
areas and the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
; the impacts they have on one another; and examines these processes (and responses) at various scales see also: urban climate
Urban climate
Urban climate refers to climatic conditions in an urban area that differ from neighboring rural areas and are attributable t urban development. Urbanization tremendously changes the form of the landscape and also produces changes in an area's air.-Rainfall:...
History
Luke HowardLuke Howard
Luke Howard FRS was a British manufacturing chemist and an amateur meteorologist with broad interests in science...
is considered the father-figure of urban climatology based on his book The Climate of London, which contained continuous daily observations from 1801 to 1841 of wind direction, atmospheric pressure, maximum temperature, and rainfall .
Urban climatology has gained much momentum in recent centuries based on global industrialization and more importantly, urbanization
Urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....
. The process of urbanization changes the physical surroundings and induces alterations in the energy, moisture, and motion regime near the surface. Most of these alterations may be traced to causal factors such as air pollution; anthropogenic heat; surface waterproofing; thermal properties of the surface materials; and morphology of the surface and its specific three-dimensional geometry—building spacing, height, orientation, vegetative layering, and the overall dimensions and geography of these elements. Other factors that must be considered are relief, nearness to water bodies, size of the city, population density, and land-use distributions .
Research
In general, cities are warmer than their surroundings, as documented over a century ago by Howard . They are islands or spots on the broader, more rural surrounding land. Thus, cities produce an urban heat island effect on the spatial distribution of temperatures. The timing of a maximum heat island is followed by a lag shortly after sundown, as urban surfaces, which absorbed and stored daytime heat, retain heat and affect the overlying air. Meantime, rural areas cool at a rapid rate.A number of energy processes are altered to create warming, and various features lead to those alterations. City size, the morphology of the city, land-use configuration, and the geographic setting (such as relief, elevation, and regional climate) dictate the intensity of the heat island, its geographic extent, its orientation, and its persistence through time . Individual causes for heat island formation are related to city geometry, air pollution, surface materials, and anthropogenic heat emission. There are two atmosphere layers in an urban environment, besides the planetary boundary layer outside and extending well above the city: (1) The urban boundary layer is due to the spatially integrated heat and moisture exchanges between the city and its overlying air. (2) The surface of the city corresponds to the level of the urban canopy layer. Fluxes across this plane comprise those from individual units, such as roofs, canyon tops, trees, lawns, and roads, integrated over larger land-use divisions (for example, suburbs). The urban heat island effect has been a major focus of urban climatological studies, and in general the effect the urban environment has on local meteorological
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
conditions.
Other Research within the field is focused on Air quality, Radiation Fluxes
Earth's energy budget
The Earth can be considered as a physical system with an energy budget that includes all gains of incoming energy and all losses of outgoing energy. The planet is approximately in equilibrium, so the sum of the gains is approximately equal to the sum of the losses.Note on accompanying images:...
, Micro-Climates and even issues traditionally associated with architectural design and engineering, such as Wind Engineering
Wind engineering
Wind engineering analyzes effects of wind in the natural and the built environment and studies the possible damage, inconvenience or benefits which may result from wind. In the field of structural engineering it includes strong winds, which may cause discomfort, as well as extreme winds, such as in...
.
Climate change
The study of Urban Climatology is strongly linked to research surrounding global climate change: as centres for socio-economic activities, cities produce large amounts of Green House Gases, most notably CO2 as a consequence of human activities such as transport, development (e.g. concrete production), waste related to heating and cooling requirements etc.Furthermore globally, cities are said to grow into the 21st century (and beyond) due to the opportunities they present and as a consequence of globalization - as they grow and develop the landscapes in which they inhabit will change so too will the atmoshpere resting above them, increasing emissions of GHG's thus contributing to the global green house effect.
Finally, many cities are vulnerable to the projected consequences of climate change (sea level rise, changes in temperature , precipitation, storm frequency) as most develop on or near coast-lines, nearly all produce distinct urban heat islands and atmospheric pollution: as areas in which there is concentrated human habitation these effects potentially will have the largest and most dramatic impact (e.g. France's heat wave in 2003) and thus are a major focus for urban climatology..