Earth’s Weather

Layers of the Atmosphere  Earth’s atmosphere is divided into five layers. It is thickest near the surface and thins out with height until it eventually merges with space.

Atmosphere Review  Troposphere – The first layer above the surface, contains half of the Earth's atmosphere. Weather occurs in this layer. TroposphereWeather  Stratosphere - Many jet aircrafts fly in this layer because it is very stable. The ozone layer absorbs harmful rays from the sun, and gets hotter higher.  Mesosphere - Meteors or rock fragments burn up in this portion of the atmosphere.  Thermosphere - This is the layer with auroras also where the space shuttle orbits. Heats up as it gets higher due to absorbing high energy radiation.  Exosphere – This is the area where the atmosphere merges into space, this area is extremely thin. Exosphere  Troposphere – The first layer above the surface, contains half of the Earth's atmosphere. Weather occurs in this layer. TroposphereWeather  Stratosphere - Many jet aircrafts fly in this layer because it is very stable. The ozone layer absorbs harmful rays from the sun, and gets hotter higher.  Mesosphere - Meteors or rock fragments burn up in this portion of the atmosphere.  Thermosphere - This is the layer with auroras also where the space shuttle orbits. Heats up as it gets higher due to absorbing high energy radiation.  Exosphere – This is the area where the atmosphere merges into space, this area is extremely thin. Exosphere

Explanations of Weather  What causes weather? –Heat transfer  Convection (Main cause)  Conduction  Radiation –Changes of state in the water cycle transfer energy too  Ex: Precipitation, evaporation & condensation  What causes weather? –Heat transfer  Convection (Main cause)  Conduction  Radiation –Changes of state in the water cycle transfer energy too  Ex: Precipitation, evaporation & condensation

Weather  As a result of heat and moisture differences air that lingers over an ocean or desert will become dry or humid matching the surface below.

Four Main Air masses that effect us  1) Continental polar air mass –over Northern Canada and Alaska  2) Maritime polar air mass –over North Pacific Ocean  3) Maritime tropical air mass –over the Gulf of Mexico and Caribbean  4) Continental air mass –over the southwestern states and Mexico  1) Continental polar air mass –over Northern Canada and Alaska  2) Maritime polar air mass –over North Pacific Ocean  3) Maritime tropical air mass –over the Gulf of Mexico and Caribbean  4) Continental air mass –over the southwestern states and Mexico

Air Masses

Air and pressure  Gas molecules in air are constantly moving and pushing on each other causing air pressure. Air pressure is measured with a barometer. Mercury barometers use a glass tube of mercury. Air pressure forces the mercury up the column and its height is measured.  Gas molecules in air are constantly moving and pushing on each other causing air pressure. Air pressure is measured with a barometer. Mercury barometers use a glass tube of mercury. Air pressure forces the mercury up the column and its height is measured.

Air pressure Aneroid barometers use thin metal cans with most of the air pumped out of them. The shape of the can changes as the air pressure does, which moves a needle or pen on a chart.

Units of pressure: The height of the mercury column can be measured in inches or millimeters. Sea level air pressure: mb or inches Hg. Decreasing pressure often means a storm is approaching. The height of the mercury column can be measured in inches or millimeters. Sea level air pressure: mb or inches Hg. Decreasing pressure often means a storm is approaching.

Types of pressure  The uneven heating of the earth results in uneven air pressure on the earth  Look at a weather map - –"H" marks areas that have high pressure  High pressure areas are generally produce to clear skies  High pressure prevents water vapor from rising to form clouds –"L" marks the low pressure  low pressure areas often produce clouds & precipitation  The uneven heating of the earth results in uneven air pressure on the earth  Look at a weather map - –"H" marks areas that have high pressure  High pressure areas are generally produce to clear skies  High pressure prevents water vapor from rising to form clouds –"L" marks the low pressure  low pressure areas often produce clouds & precipitation

Wind –Air moves from high pressure to low pressure  The closer a high and low pressure areas are to each other, the stronger the winds –Winds in a high pressure area  move clockwise –Winds in a lower pressure area  move counter-clockwise –Air moves from high pressure to low pressure  The closer a high and low pressure areas are to each other, the stronger the winds –Winds in a high pressure area  move clockwise –Winds in a lower pressure area  move counter-clockwise

Weather Fronts When air masses meet a front develops – Fronts are where cold and warm air meet, they can produce weather and violent storms. –Over time wind brings air to equalize the pressure when a high pressure collides with a low pressure area. When air masses meet a front develops – Fronts are where cold and warm air meet, they can produce weather and violent storms. –Over time wind brings air to equalize the pressure when a high pressure collides with a low pressure area.

Types of Fronts  1) Warm Front –The lighter warm air slips over the heavier cold air forming a gradual slope. –Clouds increase and drop in height.  1) Warm Front –The lighter warm air slips over the heavier cold air forming a gradual slope. –Clouds increase and drop in height.

Types of fronts 2) Cold Front –Heavier cold air shoves under the lighter warm air  This pushes the warmer wetter air up very fast condensing the moisture with it causing clouds to form. 2) Cold Front –Heavier cold air shoves under the lighter warm air  This pushes the warmer wetter air up very fast condensing the moisture with it causing clouds to form.

Types of fronts  3 ) Stationary Front –Neither the cold or warm air is advancing  3 ) Stationary Front –Neither the cold or warm air is advancing

Technology  Humans can use technology to predict the weather –Thermometers - temperature readings –Barometers - air pressure –Hygrometer - relative humidity –Wind Vanes - direction of wind –Anemometer - speed of wind –Rain gauge - amount of rainfall –Weather satellites, weather planes, weather balloons, and radar - are used for measuring many weather components.  Humans can use technology to predict the weather –Thermometers - temperature readings –Barometers - air pressure –Hygrometer - relative humidity –Wind Vanes - direction of wind –Anemometer - speed of wind –Rain gauge - amount of rainfall –Weather satellites, weather planes, weather balloons, and radar - are used for measuring many weather components.