ATMOSPHERIC LAYERS

TROPOSPHERE We live here! – (nearest Earth’s surface) Weather occurs here! Contains 80% of atmosphere’s mass – Airplanes require density to promote lift As altitude increases, temperature & air pressure decreases – Ex 1: top of mountain vs. sea level Temp. Variation creates air mass movement - (humidity, formations, etc…) Convection turns air over

STRATOSPHERE Above Troposphere Clear dry layer Contains Ozone layer (absorbs energy from the sun & turns it into heat) – ….WARMS air above it – …PROTECTS us from harmful UV rays as gas molecules absorb solar radiation

MESOSPHERE Coldest Layer – “sandwiched” between the … 1.Stratosphere : filters UV light (sun’s heat) & 2.Thermosphere: absorbs UV rays (sun’s heat) Meteors burn up here – Objects moving thru gas (air) encounters resistance as it pushes molecules out of the way 1. causing FRICTION 2. creating HEAT 3. Temp. rises, meteor GLOWS as it burns

THERMOSPHERE Above the Mesosphere Air is very thin – Atoms are sparse & molecules are broken down- allows radio comm. Very hot! – Sunlight strikes this layer first – very sensitive to solar activity Can feel cold! Molecules are far apart but very DENSE so they ABSORB a significant part of the sun’s radiation.