AtmosphereAtmosphere

Chapter 11Chapter 11

Structure of AtmosphereStructure of Atmosphere

Troposphere- closest to earth; contains most of Troposphere- closest to earth; contains most of mass of atmosphere; general decrease in temp mass of atmosphere; general decrease in temp (bottom (bottom top) top)

Stratosphere- Second LayerStratosphere- Second Layer– Contains Ozone LayerContains Ozone Layer absorbs ultraviolet radiation absorbs ultraviolet radiation

heated layerheated layer Mesosphere (middle)- temperature decreasesMesosphere (middle)- temperature decreases Thermosphere- few air moleculesThermosphere- few air molecules temp rises to temp rises to

10001000°C°C Exosphere- Outer Layer; only H & He found here; Exosphere- Outer Layer; only H & He found here;

no boundary between it and spaceno boundary between it and space

Solar Radiation p275Solar Radiation p275

6% Reflected by atmosphere6% Reflected by atmosphere 25% Reflected by clouds25% Reflected by clouds 4% Reflected by Earth’s surface4% Reflected by Earth’s surface 15% Absorbed by atmosphere15% Absorbed by atmosphere 50% Absorbed by Earth’s surface50% Absorbed by Earth’s surface

Measuring the AtmosphereMeasuring the Atmosphere

Temperature- how fast molecules move Temperature- how fast molecules move aroundaround– Heat- transfer of energyHeat- transfer of energy

Dew Point- temp to which air must be Dew Point- temp to which air must be cooled to be saturated (hold as much water cooled to be saturated (hold as much water as possibleas possible condensation) condensation)– Air masses cool 10Air masses cool 10°C for every 1000m in °C for every 1000m in

altitudealtitude– Clouds form when water reaches dew pointClouds form when water reaches dew point

Measurement– Cont’dMeasurement– Cont’d

Wind- Cool air (more dense) sinks & forces Wind- Cool air (more dense) sinks & forces warm (less dense) air upwardwarm (less dense) air upward– Air moves b/c earth is heated unevenly creating Air moves b/c earth is heated unevenly creating

imbalancesimbalances High and Low pressure High and Low pressure

Humidity- amount of water vapor in the airHumidity- amount of water vapor in the air– Relative humidity (%)= (amt of water Relative humidity (%)= (amt of water

vapor)/(amt capable of holding)vapor)/(amt capable of holding)

CloudsClouds

Condensation Nuclei- small dirt particles in Condensation Nuclei- small dirt particles in atmosphere that allow water to condenseatmosphere that allow water to condense

Orographic lifting- at mountain air is forced Orographic lifting- at mountain air is forced up- causing water vapor to travel up (colder up- causing water vapor to travel up (colder air) and reach its dew pointair) and reach its dew point condensing condensing

Collision of air masses- causes uplift of Collision of air masses- causes uplift of warm air and therefore condensationwarm air and therefore condensation

TypesTypes

HeightHeight– Cirro- above 6000mCirro- above 6000m– Alto- 2000-6000mAlto- 2000-6000m– Strato- below 2000mStrato- below 2000m

ShapeShape– Cirrus-”hair” wispy, stringyCirrus-”hair” wispy, stringy– Cumulus- “pile or heap” puffy, lumpy cloudsCumulus- “pile or heap” puffy, lumpy clouds– Stratus- “layer” sheets of cloudsStratus- “layer” sheets of clouds– Nimbus “cloud” low gray rain cloudsNimbus “cloud” low gray rain clouds

Special CloudsSpecial Clouds

Vertical Development- if cloud is warmer Vertical Development- if cloud is warmer than surrounding air/ground, cloud will grow than surrounding air/ground, cloud will grow upwardsupwards thunderstorm thunderstorm– Cumulonimbus CloudCumulonimbus Cloud

PrecipitationPrecipitation

Water droplets collide & join into larger Water droplets collide & join into larger droplets (coalescence)droplets (coalescence) too heavy to carry too heavy to carry

Sleet (ice pellets) form when droplets are Sleet (ice pellets) form when droplets are carried back up into the cloud, freezing itcarried back up into the cloud, freezing it

Hail- layers and layer of sleet built upHail- layers and layer of sleet built up