What is Weather?
Weather describes atmospheric conditions in a given location over a short period of time, such as a day or a week. The atmospheric conditions include temperature, precipitation, wind, humidity, atmospheric pressure and the presence of fog, mist or cloud cover.
What Causes Weather?
The interactions of water air and the energy from the Sun contribute to our weather. Energy from the Sun heats up the atmosphere, creating winds and other air movements.
Water in oceans, lakes etc. evaporates, cools and condenses. This process leads to cloud formation and can produce precipitation. Ocean water moves currents from the poles to the equator and vice versa. The combination of air and water movements creates weather.
What is Climate?
Climate describes the average of weather in a region over a long period of time. It gives you a range of temperatures that you might expect at a certain time of year, i.e. during summer, the climate in Southern Ontario is warm and humid.
Vladimir Koeppen used temperature, precipitation and plant communities to identify climate zones. The following is an example of the Earth’s climate zones. Note that the Continental climate zone in your textbook is subdivided into warm summer, cool summer and subarctic zones.
In the last 30 years, a new method of climate classification was developed to focus on the ecology of the regions. These climate zones are called ecoregions. Ecoregions are based on landforms, soil, plants, animals and climate. As well, they take human factors such as crops and urban centres into consideration.
Note that Canada has developed its own ecozones that are very similar to global ecoregions. In Canada’s system, major ecozones are divided into smaller ecoregions.
A bioclimate profile is a series of graphs that show temperature and moisture conditions at a given location, in other words they describe the climate. As well, bioclimate profiles can display a location’s projected climate 40 to 80 years into the future.
Factors Affecting Climate
- The distance from the equator (latitude)
- The presence of large bodies of water
- The presence of ocean or air currents
- Land formations
- The height above sea level (altitude)