tHE ATMOSPHEREtHE ATMOSPHERE

aTMOSPHERIC pRESSURE

Air Pressure- the measure of the force with which the air molecules push on a surface.

Air pressure changes throughout the atmosphere

The atmosphere is held by a planet’s gravity

Temperature

Altitude- the height of an object above the Earth’s surface.

Air temperature also changes as you increase altitude.

tEMPERATURE AND hEAT

Temperature- a measure of the average energy of particles in motion.

A high temperature means that the particles are moving fast.

Heat- transfer of energy between objects at different temperatures.

Energy in the ATMOSPHERE

Radiation- the transfer of energy as electromagnetic waves. (Sunlight)

The radiation absorbed by land, water, and atmosphere is changed into thermal (heat) energy

Conduction- is the transfer of thermal energy from one material to another by direct contact.

Energy in the Atmosphere

Convection- the transfer of thermal energy by the circulation or movement of a liquid or gas.

The continual process of warm air rising and cool air sinking creates a circular movement of air called convection current.

Greenhouse effect

50% of the radiation that enters the Earth’s atmosphere is absorbed by the Earth’s surface.

The Earth’s heating process, in which the gases in the atmosphere trap thermal energy, is known as the greenhouse effect.

A rise in average global temperature is called global warming.

Atmospheric Pressure and Winds

Wind is moving air

Wind is created by differences in air pressure.

Because air moves from areas of high pressure areas of low pressure. Winds generally move from the poles to the equator.

Atmospheric pressure and winds

The curving of moving objects, such as wind, by the Earth’s rotation is called the Coriolis effect.

Types of Winds

There are two mains of winds: local winds and global winds

Local Winds generally move short distances and can blow from any direction

Global Winds are part of a pattern of air circulation that moves across the Earth.

Types of Winds

In both hemispheres, the winds that blow from 30º latitude to the equator are called trade winds.

The westerlies are wind belts found in both the Northern and Southern Hemispheres between 30º and 60º latitude.

Type of Winds

The polar easterlies are wind belts that extend from the poles to 60º latitude in both hemispheres.

The jet streams are narrow belts of high-speed winds that blow in the upper troposphere and lower stratosphere.

Air Pollution

Primary pollutants are pollutants that are put directly into the air by human or natural activity.

Example: ash and soot are primary pollutants

Air Pollution

Secondary pollutants are pollutants that form from the chemical reactions that occur.

Ozone and smog are secondary pollutants.

Precipitation that contains acids from air pollution is called acid precipitation.