Difficulty in forecasting for microclimates
10th September, 2014
In previous blogs we have made mention to the fact that weather conditions can vary greatly, even across a very small area. These microclimates mean that whilst it may be necessary to carry out gritting at one client's site, another client just a few miles down the road may not be at risk.
Microclimates are local atmospheric zones where the climate differs from the surrounding area. These zones can range in size from a few square feet to several square miles and are influenced by a number of contributing factors including:
The higher you are above sea level, the colder the temperature will be. This occurs because the air is thinner at higher altitudes, thus it absorbs and retains less heat. The temperature usually decreases by 1 degree Celsius for every 100 metres in altitude that you climb.
Distance From The Sea
As a result of oceans heating up and cooling much more slowly than land, coastal locations tend to be much cooler in the summer and warmer in the winter compared to inland locations at a similar latitude and altitude. For example, Glasgow is at similar latitude to Moscow, but experiences much milder winters as a result of being closer to the coast.
The direction of prevailing winds can impact upon temperatures and weather conditions:
- Winds blowing off the sea will often bring rain to the coast and dry weather to inland areas.
- Winds blowing from warm inland areas, such as Africa, tend to be warm and dry.
- Winds blowing from cooler inland areas, such as central Europe, will often be cooler and dry.
- The UK most frequently experiences south westerly winds from the Atlantic, bringing cool winds in the summer and mild winds in the winter.
Urban climates refer to atmospheric conditions (temperature, humidity, wind speed/direction and air quality) in an urban area that differ from those in the surrounding rural environment. On average urban temperatures are between one and three degrees Celsius higher, but can be as much as 10 degrees Celsius higher than rural environments under calm and cloud-less conditions.
Hills and Mountains
- Anabatic/Upslope Winds: During the day, sun facing hills, mountain slopes and the air above them get heated faster than the adjacent atmosphere. As a result the density of the air decreases, causing it to rise. This causes more air to rise from below to replace it, producing wind.
- Katabatic/Gravity/Downslope Winds: In the evenings, as the highland loses heat, the air coming into contact with it also begins to cool. This causes it to become denser than the air around it and it therefore begins to flow downhill, generating a wind.
One or more of these factors can have a direct impact upon local climates. Our team are trained to interpret data from the Met Office and Weatherquest to ensure that where necessary our clients are protected from the risk of snow and ice.