Earth's Atmosphere Troposphere Stratosphere Four distinct layers thermal characteristics, chemical composition, movement, and density Troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers the most dense higher in this layer, temperature drops from about 17 to -52C almost all weather is in this region Stratosphere extends to 50 kilometers (31 miles) high dry and less dense temperature in this region increases gradually to -3C Contains the ozone layer

extends to 600 kilometers (372 miles) high Mesosphere extends to 85 kilometers (53 miles) high temperatures again fall as low as -93C chemicals are in an excited state, as they absorb energy Thermosphere extends to 600 kilometers (372 miles) high temperatures in this region can go to 1,727C Exosphere starts at the top of the thermosphere and continues until it merges with interplanetary gases, or space Mostly Hydrogen and Helium at extremely low densities

Temperature Profile of the Earth's Atmosphere http://resources.yesican.yorku.ca/trek/scisat/final/grade9/trans_temperature_profile. html

Composition of the Atmosphere Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%) other stuff: water (H2O, 0 - 7%) "greenhouse” gases or Ozone (O, 0 - 0.01%) Carbon Dioxide (CO2, 0.01-0.1%)

How’s the WEATHER??? Weather vs Climate Weather - conditions in the TROPOSPHERE at a particular time and place Climate - weather patterns that are typical for a larger region over a longer period of time What factors affect the weather??? heat from the sun atmospheric pressure moisture in the air (humidity)

Some like it HOT!!! RADIATION - energy from the sun transfer of energy by electromagnetic waves 20% absorbed by clouds and atmosphere 50% absorbed by surface 5% reflected by the surface 25% reflected by clouds and atmosphere CONDUCTION - transfer of energy from fast-moving molecules to slow-moving air is heated by the radiant energy absorbed by the surface CONVECTION - transfer of heat due to different densities Step 1 heated air becomes less dense Step 2 rises through the cooler heavier air above it Step 3 cooler air SINKS toward the surface then.... repeat steps 1 - 3 CONVECTION CURRENT

You think you’re under pressure??? atmospheric pressure force exerted by the weight of the air High pressure Low pressure

High pressure vs low pressure Too much pressure??? High pressure vs low pressure High- cool air is dense so it sinks Low - warm air is less dense soooo? Between these pressures wind is created... what determines the strength of the wind? Wind - movement of air from one place to another ****all winds are caused by temperature and pressure differences uneven heating of earth’s surfaces!!

Breezy Watch

The Hydrologic Cycle Evaporation water heated by the sun surface molecules become energized rise as invisible vapor into the atmosphere. Transpiration Water vapor emitted from plant leaves growing plant transpires 5 to 10 times as much water as it can hold at once Condensation Water vapor rises,cools and condenses on particles of dust becomes liquid again or turns directly into a solid (ice, hail or snow) water particles collect and form clouds Precipitation rain, snow and hail comes from clouds Clouds move over the world, propelled by air currents they cool becoming saturated with water water begins to fall as rain, snow or hail

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/smry.rxml

How wet is your little brother?? Relative Humidity water vapor actually in the air the maximum it can hold at that temperature x 100 How does HEAT affect humidity?? What is saturated air?? What is the dew point?? As it measures up...... psychrometer measures the amount of relative humidity in the air

How much water can air hold? Dependent on temperature Reported in density g/m3 The warmer the air…the more it can hold 30 C ? 30 g/m3

x 100 water vapor actually in the air At 25 C the actual water vapor pressure is 10g/m3 What is the relative humidity? water vapor actually in the air the maximum it can hold at that temperature x 100 RH = (10g/m3 / 20g/m3) X 100 = 50%

Coriolis Effect Once air has been set in motion by the pressure gradient force, it undergoes a deflection from its path. This deflection is called the "Coriolis force" and is a result of the earth's rotation. pressure gradient results in a net force that is directed from high to low pressure - pressure gradient force ???????                         http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml

Geostrophic Wind Results from pressure gradient and Coriolis force http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/geostrophic.rxm