World Geography Weather and Climate

Getting Started What kind of weather do we experience in Greater Vancouver?

Some Basic Definitions Weather Atmospheric conditions at any point in time Climate Long term averages in temperature and precipitation. Meteorologist Studies weather. Climatologist Studies climate.

Climate Climate is the average weather usually taken over a 30-year time period for a particular region and time period. Climate is not the same as weather, but rather, it is the average pattern of weather for a particular region. Weather describes the short-term state of the atmosphere.

Temperature The warmth or coolness of the air. Temperature is measured with a thermometer.

Air Pressure What is Air Pressure? Air has pressure because it contains gasses such as nitrogen and oxygen which have mass and therefore exert pressure on the earth’s surface. High air pressure = dry conditions Low air pressure = clouds and precipitation With low air pressure, molecules rise reduces pressure on the earth. As the molecules rise they cool and the water vapor in it turns to water droplets. With high air pressure, the opposite occurs. Level pressure is the air pressure one can expect on a fair day with partly cloudy skies.

Air Pressure: How it Works? The Pressure of the air causes things like hot air balloons to rise The difference in the speed of the air affects the pressure and allows the wing to keep the plane in the air

Air Pressure: How its Measured? Air pressure is measured with a barometer

Relative Humidity & Dew Point Is the amount of water vapour in a given volume of air divided by the maximum amount of water vapour that volume of air could contain at a given temperature before it would begin to condense into water droplets. Dew Point: The dew point is the temperature to which the air must be cooled in order to reach saturation or 100% relative humidity. Foggy conditions, drizzle, or heavy rainfall are associated with 100% relative humidity.

Relative Humidity & Dew Point