Microclimate
Overview
 
A microclimate is a local atmospheric zone where the climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 differs from the surrounding area. The term may refer to areas as small as a few square feet (for example a garden bed) or as large as many square miles. Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavily urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and reradiate that heat to the ambient air: the resulting urban heat island
Urban heat island
An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas. The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon. The temperature difference usually is larger at night...

 is a kind of microclimate.

Another contributing factor to microclimate is the slope or aspect
Aspect (geography)
In physical geography, aspect generally refers to the horizontal direction to which a mountain slope faces. For example, a slope on the eastern edge of the Rockies toward the Great Plains is described as having an easterly aspect...

 of an area.
Encyclopedia
A microclimate is a local atmospheric zone where the climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 differs from the surrounding area. The term may refer to areas as small as a few square feet (for example a garden bed) or as large as many square miles. Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavily urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and reradiate that heat to the ambient air: the resulting urban heat island
Urban heat island
An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas. The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon. The temperature difference usually is larger at night...

 is a kind of microclimate.

Another contributing factor to microclimate is the slope or aspect
Aspect (geography)
In physical geography, aspect generally refers to the horizontal direction to which a mountain slope faces. For example, a slope on the eastern edge of the Rockies toward the Great Plains is described as having an easterly aspect...

 of an area. South-facing slopes in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

 and north-facing slopes in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 are exposed to more direct sunlight than opposite slopes and are therefore warmer for longer.

The area in a developed industrial park may vary greatly from a wooded park nearby, as natural flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...

 in parks absorb light and heat in leaves, that a building roof or parking lot just radiates back into the air. Advocates of solar energy argue that widespread use of solar collection can mitigate overheating of urban environments by absorbing sunlight and putting it to work instead of heating the foreign surface objects.

A microclimate can offer an opportunity as a small growing region
Growing region
A growing region is an area suited by climate and soil conditions to the cultivation of a certain type of crop or plant group.Most crops are cultivated not in one place only, but in several distinct regions in diverse parts of the world...

 for crops that cannot thrive in the broader area; this concept is often used in permaculture
Permaculture
Permaculture is an approach to designing human settlements and agricultural systems that is modeled on the relationships found in nature. It is based on the ecology of how things interrelate rather than on the strictly biological concerns that form the foundation of modern agriculture...

 practiced in northern temperate climates. Microclimates can be used to the advantage of gardeners who carefully choose and position their plants. Cities often raise the average temperature by zoning
Zoning
Zoning is a device of land use planning used by local governments in most developed countries. The word is derived from the practice of designating permitted uses of land based on mapped zones which separate one set of land uses from another...

, and a sheltered position can reduce the severity of winter. Roof garden
Roof garden
A roof garden is any garden on the roof of a building. Besides the decorative benefit, roof plantings may provide food, temperature control, hydrological benefits, architectural enhancement, habitats or corridors for wildlife, and recreational opportunities....

ing, however, exposes plants to more extreme temperatures in both summer and winter.

Tall buildings create their own microclimate, both by overshadowing large areas and by channelling strong winds to ground level. Wind effects
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...

 around tall buildings are assessed as part of a microclimate study.

Microclimates can also refer to purpose made environments, such as those in a room or other enclosure. Microclimates are commonly created and carefully maintained in museum display and storage environments. This can be done using passive methods, such as silica gel
Silica gel
Silica gel is a granular, vitreous, porous form of silica made synthetically from sodium silicate. Despite its name, silica gel is a solid. It is a naturally occurring mineral that is purified and processed into either granular or beaded form...

, or with active microclimate control devices.

Cities and Regions Known for Microclimates

San Francisco is a city with microclimates and submicroclimates. Due to the city's varied topography and influence from the prevailing summer marine layer, weather conditions can vary by as much as 9°F (5°C) from block to block.

The region as a whole, known as the San Francisco Bay area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...

 can have a wide range of extremes in temperature. In the basins and valleys adjoining the coast, climate is subject to wide variations within short distances as a result of the influence of topography on the circulation of marine air. The San Francisco Bay Area offers many varieties of climate within a few miles. In the Bay Area, for example, the average maximum temperature in July is about 64 °F (17.8 °C) at Half Moon Bay
Half Moon Bay, California
Half Moon Bay is a coastal city in San Mateo County, California, USA. Its population was 11,324 as of the 2010 census. Immediately at the north of Half Moon Bay is the Pillar Point Harbor and the unincorporated community of Princeton-by-the-Sea....

 on the coast, 87 °F (30.6 °C) at Walnut Creek
Walnut Creek, California
Walnut Creek is an incorporated city located east of the city of Oakland. It lies in the East Bay region of the San Francisco Bay Area. While not as large as neighboring Concord, Walnut Creek serves as the business and entertainment hub for the neighboring cities within central Contra Costa...

 only 25 miles (40.2 km) inland, and 95 °F (35 °C) at Tracy
Tracy, California
Tracy is the second most populated city in San Joaquin County, California, United States and an exurb of the San Francisco Bay Area. The population was 82,922 at the 2010 census.-History:...

, just 50 miles (80.5 km) inland.

The Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

 and San Diego areas are also subject to phenomena-typical of a microclimate. As such, the temperatures can vary as much as 18°F (10°C) between inland areas and the coast, with a temperature gradient of over one degree per mile (1.6 km) from the coast inland. Southern California has also a weather phenomenon called "June Gloom or May Grey", which sometimes gives overcast or foggy skies in the morning at the coast, but usually gives sunny skies by noon, during late spring and early summer.

Calgary, Alberta is also known for its microclimates. Especially notable are the differences between the downtown and river valley/flood plain regions and the areas to the west and north. This is largely due to an elevation difference within the city's boundaries of over 1000 ft (304.8 m), but can also be attributed somewhat, to the effects of the seasonal Chinooks
Chinook wind
Chinook winds , often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies and Great Plains meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest.Chinook is claimed...

.

Halifax, Nova Scotia also has numerous microclimates. Coastal temperatures and weather conditions can differ considerably from areas located just 5–15 km inland. This is true in all seasons. Varying elevations are common throughout the city, and it is even possible to experience several microclimates while travelling on a single highway due to these changing elevations.

Santiago, Chile
Santiago, Chile
Santiago , also known as Santiago de Chile, is the capital and largest city of Chile, and the center of its largest conurbation . It is located in the country's central valley, at an elevation of above mean sea level...

 is also subject to microclimates.

Known for its wines, the Ticino
Ticino
Canton Ticino or Ticino is the southernmost canton of Switzerland. Named after the Ticino river, it is the only canton in which Italian is the sole official language...

 region in Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 benefits from a microclimate in which palm trees and banana trees grow.

Gran Canaria
Gran Canaria
Gran Canaria is the second most populous island of the Canary Islands, with a population of 838,397 which constitutes approximately 40% of the population of the archipelago...

 is called "Miniature Continent" for its rich variety of microclimates.

Biddulph Grange
Biddulph Grange
Biddulph Grange is a National Trust landscaped gardens, in Biddulph near Stoke-on-Trent, Staffordshire, England.-Description:"Behind a gloomy Victorian shrubbery there's a gloomy Victorian mansion, but behind that lurks one of the most extraordinary gardens in Britain...it contains whole...

is very rich with microclimates as a result of the large dips and variety of very large trees alongside a large amount of water.

Soil Types

The type of soil found in an area can also affect microclimates. For example, soils heavy in clay can act like pavement, moderating the near ground temperature. On the other hand; if soil has many air pockets, then the heat could be trapped underneath the topsoil, resulting in the increased possibility of frost at ground level

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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