BISL 04-Weather and Climate

Pure Air

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IMA

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LOGY

WEATHER AND CLIMATE

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T

he atmosphere is the mass of air thatenvelops the surface of the Earth. Itscomposition allows it to regulate the quantity

and type of solar energy that reaches the surface ofthe Earth.

T

he atmosphere, in turn, absorbs energy

radiated by the crust of the Earth, the polar icecaps and the oceans, and other surfaces on theplanet. Although nitrogen is its principal

component, it also contains other gases, such asoxygen, carbon dioxide, ozone, and water vapor.

T

hese less abundant gases, along withmicroscopic particles in the air, have a greatinfluence on the Earth's weather and climate.

59° F(15° C)AVERAGE TEMPERATUREOF THE EARTH'S SURFACE

Oxygen21% Nitrogen78%

Argon0.93%

Other gases0.03%

Carbondioxide0.04%

GASES IN THE AIR

51%of solarradiation isabsorbed by theEarth's surface.

4%A small amount ofsolar radiation isreflected by the oceansand the ground.

Safe flightsThe absence ofmeteorologicalchanges in this regionmakes it safer forcommercial flights.

High mountainsAny mountains higher than 5miles (8 km) above sea level.The decrease of oxygen withaltitude makes it difficult tobreathe above 2.5 miles (4 km).

TROPOSPHERE Starts at sea level and goes to analtitude of six miles (10 km). It providesconditions suitable for life to exist. Itcontains 75 percent of the gases in theatmosphere. Meteorological conditions,such as the formation of clouds andprecipitation, depend on its dynamics. Itis also the layer that contains pollutiongenerated by human activities.

STRATOSPHERE Extends from an altitude of 6miles to 30 miles (10-50 km).The band from 12 to 19 miles(20-30 km) has a highconcentration of ozone, whichabsorbs ultraviolet radiation. Athermal inversion is producedin this layer that is expressedas an abrupt temperatureincrease beginning at analtitude of 12 miles (20 km).

MESOSPHERE Located between an altitudeof 30 to 55 miles (50-90km), it absorbs very littleenergy yet emits a largeamount of it.

This absorption

deficit causes thetemperatures to decreasefrom 60° F to -130° F (20° Cto -90° C) in the upperboundary of the mesopause.

THERMOSPHERE Found between an altitudeof 55 and 300 miles (90-500 km).

The O

2

and the N

2

absorb ultraviolet rays andreach temperatures greaterthan 1,800° F (1,000° C).These temperatures keepthe density of gases in thislayer very low.

EXOSPHERE This layer, which begins at analtitude of about 310 miles(500 km), is the upper limit ofthe atmosphere.

H

ere material

in plasma form escapes fromthe Earth, because the magneticforces acting on them aregreater than those of gravity.

Tropical stormclouds

Cirrus

20%of solar radiationis reflected bythe clouds.

Noctilucent cloudsThe only clouds thatexist above thetroposphere.

They are

the objects of intensestudy.

ForecastsWeather balloons areused to make weatherforecasts.

They record

the conditions of thestratosphere.

Cosmic raysCome from the Sun andother radiation sources inouter space. When theycollide with the moleculesof gas in the atmosphere,they produce a rain ofparticles.

Rocket probesUsed for scientificstudies of thehigher regions ofthe atmosphere

AurorasCreated in the upper layersof the atmosphere when thesolar wind generateselectrically charged particles

Meteorsbecome superheated byfriction with themolecules of the gas inthe atmosphere.Particles that skipacross the atmosphereare called shooting stars.

19%of solar radiationis absorbed bythe gases in theatmosphere.

6%of solar radiationis reflected bythe atmosphere.

DISTANT ORBITSPolar meteorologicalsatellites orbit in theexosphere. Military satellitesAir friction shortenstheir useful life.

SOLAR RADIATION

GREENHOUSEEFFECTProduced by theabsorption ofinfrared emissionsby the greenhousegases in theatmosphere.

This

naturalphenomenon helpsto keep the Earth'ssurfacetemperature stable.

The Ozone Layerstops most of theSun's ultraviolet rays.