weather and climate unit #1 the atmosphere cgf3m physical geography
TRANSCRIPT
WEATHER AND CLIMATE
Unit #1The Atmosphere
CGF3MPhysical Geography
WEATHER AND CLIMATE
In order to understand weather and climate we first must understand the characteristics of where weather and climate happen.
The Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity.
WEATHER AND CLIMATE
The atmosphere has 4 main characteristics: It is fluid It is made up of
various gases It has mass It consists of layers
The atmosphere is fluid
Fluids are substances that can flow
Most fluids are liquid or gas
The atmosphere can flow from one place to another
WEATHER AND CLIMATE
WEATHER AND CLIMATE
When foreign substances (smoke, dust, pesticides, chemicals) enter the air the atmosphere can spread it considerable distances from the point of origin
WEATHER AND CLIMATE
The Atmosphere is made up of various gases
78% nitrogen 21% oxygen 0.93% argon 0.04% carbon dioxide Trace amounts of other
gases, in addition to water vapor
WEATHER AND CLIMATE
The Atmosphere has Mass
Fluids occupy space and have mass
The weight of air pushing down on the earth’s surface is referred to as air pressure
WEATHER AND CLIMATE
Air Pressure is affected by the heating and cooling of the earth’s surface.
Hot air rises, so the air pressure at higher elevations is less than that of the cool air at lower elevations
Air moves from areas of high pressure to areas of low pressure
WEATHER AND CLIMATE
When air rises, it leaves behind an area of low pressure, because the upward moving air is not pressing so hard on the surface. Areas of high pressure are formed where is sinking back down, and so pushing down harder.
WEATHER AND CLIMATE
Air pressure is measured in millibars or kilopascals.
On a weather map places across the country with the same air pressure are joined together with line, forming isobars
WEATHER AND CLIMATE
Weather associated with high and low pressure systems are very distinct
Lows: Relatively warm, moist air
Highs: Relatively cool and dry
WEATHER AND CLIMATE
The atmosphere consists of five layers with transitional regions between most
Each layer possesses individual characteristics
The most important differences between each layer are in the air pressure and temperature