The Atmosphere

The Atmosphere

1. Section 6: Winds

   • Global Wind Belts
     • The major global wind belts are the trade winds, the polar easterlies, and the prevailing westerlies. 
     • Doldrums
       • Cool air moves into the area , but is warmed rapidly and rises before it moves very far.
     • Horse Latitude
       • Latitude is distance from the equator, measured in degrees.
     • Trade Winds
       • When the cold air over the horse latitudes sinks, it produces a region of high pressure.This high pressure causes surface winds to blow both toward equator and away from it.
     • Prevailing Westerlies
       • In the mid-latitude, between 30 degrees and 60 degrees north and south, winds that blow toward the poles are turned toward the east by the Coriolis effect. 
     • Polar Easterlies
       • Cold air near the poles sinks and flows back toward lower latitudes.  
     • Jet Streams
       • About 10 kilometers above Earth's surface are bands of high-speed winds called jet streams.
   • Local Winds
     • Local winds are caused by the unequal heating of Earth's surface within a small area.
     • Sea Breeze
       • A sea breeze or a lake breeze is a local wind that blows from an ocean or lake.
     • Land Breeze
       • The flow of air from land to a body of water is called a land breeze.
   • What is Wind
     • Winds are caused by difference in air pressure.
     • Wind-Chill Factor
       • The increased cooling a wind can cause is called the wind-chill factor.
     • Measuring Wind
       • Wind speed can be measured with an anemometer.
   • Global Winds
     • Like local winds, global winds are created by the unequal heating of Earth's surface.But unlike local winds global winds occur over a large area.
     • Coriolis Effect
       • The  way Earth's rotation makes winds curves is called the Coriolis effect.
     • Global Convection Currents

2. Section 2: Air Pressure

   • Properties of air
     • Density
       • Recall that the amount of mass in an given volume of air is its density.
     • Air Pressure
       • The force pushing on an area or surface is known as pressure. Air pressure the result of the weight of a column of air pushing down on an area.
   • Measuring Air Pressure
     • A barometer is an instrument that is used to measure air pressure. Two kinds of barometers is Mercury barometer and Aneroid barometer.
     • Mercury Barometer
       • A Mercury barometer consists of a glass tube open a the bottom end and partially filled with mercury.
     • Aneroid Barometer
       • An Aneroid barometer has an airtight metal chamber.  
     • Units of Air pressure
       • Weather reports use several different unit for air pressure. Most weather reports for the general public use inches of mercury.   
   • Altitude and the Properties of Air
     • Altitude, or elevation, is the distance above sea level, the average level of the surface of the oceans.
     • Altitude affects Air Pressure
       • Sea level air has the weight of the whole atmosphere pressing on it.
     • Altitude Also Affects Density
       • The air contains 21 percent oxygen, whether you are at sea level or on top of an mountain.

3. Section 1: The Air Around You

   • Weather is the condition of Earth's atmosphere at a particular time and place. Atmosphere is the envelope of gases that surround the planet
   • Composition of the Atmosphere
     • Particles
       • Pure air contains only gases. But pure air exists only in laboratories. 
     • Other Gases
       • Oxygen and nitrogen together make up 99 percent of dry air.
     • Water Vapor
       • Water vapor is water in the form of a gas.Water vapor is invisible.
     • Nitrogen
       • Each nitrogen molecule consists of two nitrogen atoms. Nitrogen moves in a cycle from the air soil, into living things, and then back into the air
     • Oxygen
       • Ozone is a form of oxygen that has three oxygen atoms in each molecule instead of the usual two.
     • Carbon Dioxide
       • Carbon dioxide is essential to life.Plants take in carbon dioxide from the air to make food. 
   • Importance of the atmosphere
     • Earth's atmosphere makes conditions on the Earth suitable fro living things. 
   • Air Quality
     • Pollutant are harmful substances in the air, water, or soil.
     • Sources of Pollution
       • Some pollution occurs naturally. For example, many natural processes add particles to the atmosphere.
     • Smog and Acid Rain
       • The burning of fossil fuels can cause smog and acid rain. The brown haze that develops in sunny cities is called photochemical smog.  Rain is naturally slightly acidic, but rain that contains more acid than normal as known as acid rain. 
   • Improving Air Quality
     • The amounts of most major air pollutants have decreased.

4. Section 3: Layers of the Atmosphere

   • Scientists divide Earth's atmosphere into four main layers classified according to changes in temperature.These layers are the troposphere, the stratosphere, the mesosphere, and the thermosphere. 
   • The Troposphere
     • The troposphere is the layer of the atmosphere in which Earth's weather occurs.
   • The Stratosphere
     • The Stratosphere is the second layer of the atmosphere and contains the ozone layer.
   • The Mesosphere
     • The Mesosphere is the layer of the atmosphere that protects Earth's surface from being hit by most meteoroids.
   • The Thermosphere
     • The outermost layer of Earth's atmosphere is the thermosphere.

5. Section 5: Heat Transfer in the Atmosphere

   • Thermal Energy and Temperature
     • Measuring Temperature
       • Air temperature is usually measure with a thermometer.
     • Temperature Scales
       • Temperature is measured in units called degrees.Two temperature scales are commonly used: the Celsius and The Farhrenheit scale.
   • How Heat Is Transfered
     • Heat is transferred in three ways within the atmosphere :radiation, conduction, and convection.
     • Radiation
       • Recall that radiation is the direct transfer of energy by electromagnetic waves.
     • Heating the Troposphere
       • Within the troposphere, heat is transferred mostly by convection. Convection current move heat throughout the troposphere. 
     • Convection
       • The transfer of heat by the movement of a fluid is called convection.
     • Conduction
       • The direct transfer of heat from one substance to another substance that it is touching is called conduction.

6. Section 4: Energy in Earth Atmosphere

   • Energy at Earth's Surface
     • When Earth's surface is heated, it radiates most of the energy back into the atmosphere as infrared radiation.
   • Energy From the Sun
     • This energy travels to Earth as electromagnetic waves, a form of energy that can move through the vacuum of space. Radiation is the direct transfer of energy by electromagnetic waves, so the electromagnetic waves given off by the sun are called solar radiation.
     • Visible Light
       • Visible light includes all of the colors that you see in a rainbow. The different colors are the result of different wavelengths. Red and orange light have the longest wavelengths, while blue and violet light have the shortest wavelengths,
     • Non-Visible Radiation
       • One form of electromagnet energy,infrared radiation,has wavelengths that are longer than red light. The sun also gives off ultraviolet, which is an invisible form of energy with wavelengths that are shorter than violet light.
   • Energy in the Atmosphere
     • Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface. The rest passes through the atmosphere to the surface.