Q What is a microclimate?
A A microclimate is the climate in a very local region where the climate differs substantially from the larger surrounding area.
A microclimate can be detectable over an area the size of a flower bed or an entire mountain valley. The formal meteorological definition also places limits on the thickness of the atmospheric layer above a microclimate. The vertical thickness of the atmosphere of a given microclimate is generally four times the height of the surface structure. So, the height of the microclimate over a lawn is a lot smaller than the microclimate over a city or forest.
You have likely experienced a variety of microclimates. If you live by a lake you probably have noticed that the air is cooler at the shore than in the center of the city. A large blacktopped parking lot will have a different microclimate than a nearby park with grass playing fields. If you garden, you may have noticed that flowers planted close to your house will bloom earlier and die later than those in an open space far from the house - this results from the different microclimates of the two areas. Snow fences slow the wind and deposit snow downwind, generating a microclimate on one side of the fence by providing more moisture for the soil when the snow melts, a boon for vegetation growth. Farmers plant tall trees upwind of their agricultural field to change the wind speed over the field and reduce soil erosion - they are changing the microclimate of the field.
Microclimates are of particular interest to groups like farmers, gardeners and architects that might need to need manage environments to improve plant growth or make a building more energy efficient.