Weather and ClimatePart 1 - Introduction

CGF3M

Crescent School

Definitions• Weather: all the atmospheric activities that

occur at a given place at a given time. The condition of the atmosphere.

• Climate: atmospheric conditions a place has, averaged over a long period of time. The average of weather.

• Include: temperature, wind speed and direction, humidity, precipitation, pressure, cloud cover.

Weather:•Short Term•Small Scale•Difficult to predict and forecast (Daily)•Temperature, Precipitation, Humidity, Wind direction and speed, pressure•Meteorology

Climate:•Long Term•Large Scale•Easy to predict (Seasonal)•Climate is the averages of Temperature, Precipitation etc.•Climatology

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Climatic Controls

It is obvious that not all places on earth experience the same weather or climate. There are a number of factors that effect the weather or climate. They are called ‘Climatic Controls’.

Remember Grade 9 and LOWER - Near Water! This year we will change it up a bit.

There are Four basic variables that influence climate:

1.Insolation: amount of solar radiation a place receives (amount of daylight & angle of suns rays - Latitude)2.Elevation: Altitude (air pressure/heat released)3.Proximity of water bodies: (moderates, continental areas with large lakes)4.Ocean currents: movement of heat from the equator toward the poles (temperature & precipitation)

Microclimates• Subtle variations in temperature, humidity and

precipitation on a small scale.– Exposure: influence of wind on temperature and

humidity– Albedo: surfaces convert solar energy into heat

• Walk (outside) around the school one day and you will notice surprisingly different conditions around the area that contains the school

• Dark Pavement • Natural cover - grass, trees etc.• Strong Sun• The Shade• Buildings acting as barriers to the sun or wind

Exposure:

• Slopes - southern slopes receive more sun than northern slopes• Wind Chill - how cold the temperature feels to people because of the wind.• A surface that is heated by the sun will be cooled quickly if there is a strong wind that blows the heated air away quickly. This type of surface will also dry faster.

Albedo:

• Dark surfaces convert more of the available heat than light surfaces. Walk across black pavement with bare feet on a hot summer day, then walk on grass.• Objects with low albedo are cooler than objects with high albedo

Urban Heat Island:

ConcreteTall buildings - wind tunnelsCars, air conditionersSubwaysPollutions - InversionsIncreased levels of Carbon Dioxide, Carbon Monoxide, Nitrous oxide etc.

Many cities that have large parks and ravines compensate this Urban Heat Island effect.

The End

Go to Part 2 of the Weather and Climate

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