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Microclimate

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Microclimate Meaning

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Microclimate is the aggregate of environment variables including temperature, humidity, radiations, and to which plant is exposed. It is the climate near the Earth’s surface and it is distinct from the local climate or weather projection microclimate because of the earth effects and most importantly the presence of vegetation.

Microclimate occurs for example near the water bodies which may cool the atmosphere, or in heavy urban areas where brick, concrete and asphalt absorb the sun’s energy, heat up and radiate that heat to the ambient air then the resulting urban heat island is a kind of microclimate. 

The term “microclimate” is first introduced in publications such as “Climates in Miniature”: A Study of Microclimate Environment (Thomas Bedford, Franklin).


Microclimatology

The term microclimatology is defined as the scientific investigation of microclimate, and its concerned with the atmospheric layer that extends from the Earth surface to a height where the consequences of the features of the supporting surface can no longer be differentiated from the local climate (American Meteorological, 2000).


Urban Microclimate

Urban microclimate can be defined as the local climate observed in the urban areas which differed from the climate of the surrounding rural areas. Several factors are responsible for creating unhealthy urban microclimate.

Human generated heat is a biggest factor and much of it is caused by internal combustion by car engines that use fossil fuels. Cars also cause pollution and moisture to the air.  All the heat- retaining covered surface required for cars makes the climate more unhealthy. 

Other factors that are  responsible for creating unhealthy urban microclimates are poor building  constructions and designs, inferior insulating materials, and inefficient building management practice. 


Microclimate Parameters

Two microclimate parameters that define microclimate  within a certain area are temperature and humidity. 


Macro and Micro Climate

Microclimate is defined as the variations in localised climate around a building whereas microclimate is the climate of larger areas such as a region or country. The macro and micro climate has a crucial effect on both the energy and atmospheric performance of buildings during the summer season.

The construction site affects exposure to the prevailing wind, the solar radiation the building receives,  pollution level , temperature and rain penetration.


Factors Affecting Microclimate And Microclimate

The factors that adversely affect macroclimate and microclimate are discussed below.

Macroclimate is Affected By:

  • Topography- The Shape of the land

  • Sun angle exposure

  • Vegetation

  • Water body

  • Physical Infrastructure

  • Urban Layout

  • Energy Demand

  • Open Spaces

  • Vehicle Population


Microclimate is Affected by:

Outsiders Designer Control

  • Area and local climate

  • Site surrounding

  • Site shape

  • Topography features

  • Surrounding Buildings


Within Designer’s Remit

  • Location of open areas

  • Spacing and orientation of buildings

  • Form and height of building

  • Fenestration

  • Tree covers

  • Wind break

  • Ground Profiling

  • Surrounding Surface (paving grass etc)


Climate and Microclimate

Weather is defined as the atmospheric condition at a certain point of time or short period of time. It is characterized by distinct methodological events such as air velocity, temperature, air pressure, and their interactions. On the hand, climate can be defined as the average state of atmosphere and related characteristics of the underlying water or land in a particular region for a long duration. The term microclimate can be used to describe an indoor climate, i.e. the condition of the area in a certain closed space. 


Climate and Microclimate Difference

The difference between climate and microclimate is that the climate is an area of the Earth’s surface between two parallels of latitude whereas microclimate is a small, local region retaining a unique pattern of weather or weather effects that differs from the local climate. 


Did You Know?

  • North California above the Bay area is renowned for microclimate with significant temperature difference.

  • San Francisco is a city with microclimate and sub microclimates.

  • Chesapeake bay is also known for its subtropical climates.

  • The wind microclimate around buildings is the result of the buildings layout.

  • Microclimate is advantageous for gardeners who carefully choose and position their plants.

  • Tall buildings in urban areas create their own microclimate both by overshadowing arger areas and by channelising strong wind to ground level.

  • Halixa, Nova Scotia has varied microclimates.

FAQ (Frequently Asked Questions)

1. What are the Causes of Microclimate?

Ans: Microclimate is caused due to the regional differences in the proportion  of heat or water received or confined near the surface. A microclimate may differ from its surrounding by receiving more energy. Hence, it differs from its surroundings. On other hand, it may be cooler on average if it is shaded because it does not receive direct sunlight. Its humidity may differ, water may have collected there making the things damper or there may be mess water making the air drier. Also, the wind speed may be different, affecting the temperature and humidity because the wind aims to remove heat and water. Also these effects contribute in making the microclimate.

2. How Does Soil Affect Microclimate?

Ans: The composition of soil affects the climate primarily through the amount of water it retains or which evaporates from it. A soil that contains a large proportion of clay retains more moisture than one that is predominantly sand. The extent to which soil moisture retains affects the humidity and temperature of the air above it. After heavy rain, the soil contains lots of water and modifies microclimate much similar to water bodies like lakes.  Other than mineral composition of soil, the degree of coverage it has will influence moisture and temperature evaporation Bare soil will receive more light and heat than those covered by plants.

3. What are Two Main Parameters of Microclimate?

Ans: Two main parameters that define microclimate with a certain area are temperature and humidity.