EARTH’S ATMOSPHERE

Origins of the Atmosphere Boom. Our atmosphere was created by gases that vented from erupting volcanoes. Outgassing There were three main gasses emitted: 1.Water Vapor 2.Carbon dioxide 3.Nitrogen

Now the atmosphere is mainly…. If your not sure look at your….. ESRT 1.Nitrogen 2.Oxygen How did this occur? Plant life began to grow so they converted carbon dioxide to oxygen Photosynthesis

The Structure of the Atmopshere The atmosphere is broken into four layers: 1.Troposphere 2.Stratosphere 3.Mesosphere 4.Thermosphere The layers in between the spheres are called: -pauses

Changes in Air Temperature There are two cycles that control our weather: 1.The daily weather cycle 2.The season weather cycle

Daily Weather Cycle Morning pm pm

Seasonal Cycle MARCH 21-23DECEMBER 21-23JUNE 21-23SEPTEMBER 21-23

What Causes Air Pressure? Air Pressure: is the weight of the atmosphere Proof: Weigh a flat basketball compared to a basketball filled with air. At sea-level, the air pressure is nearly 15 lbs per square inch, or mb. Millibars: the metric unit of atmospheric pressure.

STRAW PROOF AIR GOES OUT OF THE STRAW SO PRESSURE DECREASES Less pressure means that the liquid has nothing holding it back so it moves up the straw

Measuring Air Pressure ometer: Instrument that measures air pressure. Use to use mercury as a liquid in it to gauge the air pressure (like a thermometer) so that is how we got the unit inches of mercury. In. of Hg We also use millibars to measure air pressure Bar

Factors that Affect Atmospheric Pressure Altitude As air rises it expands and there is less gravity pushing down on it. More elevation = less air pressure Indirect relationship Altitude (elevation) Air Pressure

Factors (cont) Temperature: If air is cooled it comes together and becomes more dense More dense air makes it heavier so there is more air pressure If air is heated it’s molecules expand and it becomes less dense Less dense air makes it lighter so there is less air pressure Air Pressure Temperature

Factors (cont) Humidity Is the amount of water vapor in the air Humid air is less dense than dry air The mass of water is less than the mass of nitrogen The atmosphere is made up of primarily which gas…. Nitrogen More humidity = less air pressure Air Pressure Humidity

Dew Point When the humidity of the air cools to a certain point, you see water in some form. This temperature in which we see water is what we call the dew point. The dew point comes mostly when the greatest change in temperature occurs which is….. (Think the daily weather cycle) The morning

How to Find the Dew Point Using a sling psychrometer you: 1.Record the dry bulb reading 2.Record the difference between the dry bulb and the wet bulb (wet bulb will always be less) 3.Go to your ESRT and match up those two numbers to find the Dew Point

Dry Bulb: 22 °C Wet Bulb: 20 °C Diff: 2°C

Relative Humidity The percentage of humidity in the air is called the relative humidity. We use a sling psychrometer to find this as well. You also use the same procedure to find the relative humidity.

Insolation IN coming SOL ar Radi ATION Definition: the sun’s electromagnetic energy that reaches the Earth.

How Does Heat Energy Travel? Heat is a form of energy because it can do work. There are three ways that heat can travel 1.Convection 2.Conduction 3.Radiation

Convection Convection is the transfer of heat flow in a fluid or a gas. Caused by a difference in density. This creates winds.

Conduction Conduction: the form of heat flow in solids that occurs when a hot substance touches a cooler substance. Ex. Metal handle of a pot on the stove. Convection Conduction

Radiation Radiation is the flow of energy as electromagnetic waves, such as visible light. Heat waves, that you feel but cannot see are also forms of radiation. Radiation does not need a medium to travel through.

Electromagnetic Spectrum

REVIEW GAME!!!! In your groups, the person with the board will: Look at the picture on the board Buzz in when they have written down the correct transfer of energy If it is correct your group gets a point If you buzz in and it is incorrect, you group loses a point If there is any calling out, that group loses a point

Conduction

Radiation

Convection

Radiation

Convection

Conduction

Convection

Radiation

All Three

Angle of Insolation Angle of Insolation depends on how high the sun is in the sky. As the sun rises and sets the a.o.i. changes, ie, the daily weather cycle. We measure the a.o.i from the horizon up to the position of the sun. Smaller angle=colder temp Larger angle (90˚)= warmer temps

A.O.I

The a.o.i also works for the seasonal weather cycle. In the Northern Hemisphere, the lowest noon time a.o.i is on Dec. 21 and the highest noon time a.o.i is on June 21. These are different because Earth is spherical. The vertical ray is the most direct amount of insolation (warmer temps), which always hits in the Tropics. All other latitudes received indirect, or slanted amounts of insolation (colder temps).

Duration of Insolation Duration of Insolation is the length of time from sunrise to sunset. When Earth has a greater duration of insolation, the temperatures increase. Direct Relationship D.O.I varies greatly with latitude. Higher the latitude, the more extreme amounts of d.o.i. Lower the latitude, the more consistent the amounts of d.o.i.

Energy Absorption Colors: darker=more absorption, less reflection lighter=less absorption, more reflection Surfaces: shiny=less absorption, more reflection textured=more absorption, less reflection

Absorption of Insolation by the Atmosphere Earth (the solid portion of it) absorbs most of the insolation that falls on it. Some that are not absorbed are: Gamma and X-Rays, which are absorbed by ozone and other gases in the upper atmosphere Long-wave radiation, which is absorbed by water vapor and carbon dioxide in the atmosphere. SOOOOOO Visible-light wavelengths easily get through the atmosphere.

Absorption of Insolation by the Atmosphere (cont) Some of the absorbed energy is changed into infrared heat waves that are reradiated from the ground (terrestrial radiation) back into the atmosphere.

Land v. Water Absorption The difference between the amount of radiation could be for one or more of the four following reasons: 1.Water has a higher specific heat than landhigher specific 2.Water reflects lower angle insolation better than land 3.Water is transparent so insolation goes down further into it 4.Convection currents bring insolation further into the hydrosphere

Specific Heat The amount of energy needed to raise the temperature of a substance by one degree.

Reflection of Insolation The Poles are colder than the Equator, even though they both get 12 months of sun and 12 months of darkness, because: 1.Snow at the Poles reflect most of the insolation 2.The Sun is lower in the sky at the Poles (a.o.i) 3.Sunlight must travel a greater distance through the atmosphere b/c the Sun is so low in the sky, so it loses energy.

Greenhouse Effect Explain it to me.

The Insolation-Temperature Lag The Insolation-Temperature Lag is the time delay between the maximum and minimum insolation and the maximum and minimum air temperature. Ex. Temp at 6AM compared to Temp at 2PM Ex. Temp of the ocean in June compare to Temp of the ocean in Ocobter.

What Causes Wind? Wind is the natural movement of air along, parallel to, Earth’s surface. These are the result of uneven heating of Earth’s surface. Warm Air Lower Pressure Cool Air Higher Pressure More DenseLess Dense WIND ALWAYS BLOWS FROM AREAS OF HIGHER PRESSURE TO LOWER PRESSURE!!!!!

Wind blows fastest where the gradient in air pressure is the greatest.

LAND AND SEA BREEZES Sea Breeze A breeze that occurs during the day as there is high pressure (cooler temps) over the water and lower pressure (warmer temps) over the land.

LAND AND SEA BREEZES Land Breeze A breeze that occurs at night when there is high pressure (cooler temps) over the land and lower pressure (warmer temps) over the water.

How Do Clouds Form? Cloud: a collection of billions of tiny droplets or ice crystals (condensation nuclei) suspended in the atmosphere. They form when the air is cooled to the dew point temperature. This occurs because as air rises into the atmosphere the air is cooled and it expands. Dry Bulb Temperature line

Coriolis Effect The Earth rotates, and because of this, the winds of the Earth curve. Rather than blowing from the Poles to Equator… In the Northern Hemisphere they curve to the right of their original path. In the Southern Hemisphere they curve to the left of their original path. This curvature is called the Coriolis Effect.

Coriolis Effect (cont) High Pressure Area: winds move clockwise Low Pressure Area: winds move counterclockwise

Pressure Systems High Pressure System: Married to Uncle Cyclone…… Anticyclone Highs are zones of divergence. When sinking air at the center causes the winds to blow outward. These bring cool and dry air with clear skies and stable conditions.

High Pressure System

Low Pressure System Low Pressure System: Cyclone Lows are zones of convergence. When rising air at the center causes the winds to blow inward. These bring warm and moist air with cloudy skies and unstable conditions.

Low Pressure System

Air Masses Air Mass: large bodies of air with uniform temperature. The movement of these bring us changes in weather. The leading edge of an air mass is a front. When a front passes, precipitation often accompanies the change in temperature, humidity, and atmospheric pressure. Then, when the air mass settles in, the weather stabilizes.

How We Categorize Air Mass The character of the air mass is determined by the geographic origin of the air that makes it up.

Geographic Origin There are two general geographic origins for air masses: 1.Out of Canada – This makes the air mass generally cold – Also, because it starts on land the air is dry – This air causes an increase in atmospheric pressure. 2.Out of the Gulf of Mexico – This makes the air mass generally warm – Also, because it starts on over water, the air is moist – This air causes a decrease in atmosphereic pressure

Meet the Air Masses!! We have developed a system of two-letter codes to identify temperature and humidity characteristics for each air mass. cP cT mP mT c=continental m= maritime P= polar T= tropic A=arctic cA

Fronts Fronts are shown by lines that separate air masses. They are often found in low pressure systems because they bring unsettled weather. Four types of fronts

Warm Front Warm Front: Is the boundary between a mass of warm air and the colder mass of air it is pushing out. Think me trying to push Mr. Roesner. Brings steady precipitation and low pressure and may take several days to pass.

Warm Front

Cold Front Cold front: Is the boundary between a mass of cold air and the warmer air it is pushing out. Think Mr. Roesner pushing me. Brings rapid cloud formation, intense precipitation, high pressure and moves quickly.

Cold Front

Stationary Front Stationary Front: The boundary between air masses that are not moving (stationary). Think Mr. Roesner and his twin brother pushing each other. Winds blow in opposite directions so it does not move.

Stationary Front

Occluded Front Occluded Front: Forms when warm air is pushed above Earth’s surface by cooler air that is closing in from both sides. Think of a mosh pit. Rainy, unsettled weather.

Occluded Front

Windward/ Leeward Adiabatic: as air rises it reduces air pressure and this causes the air to expand and cool