Chapter 1: The Chapter 1: The Earth’s Earth’s

AtmosphereAtmosphere By the end of this chapter you should:By the end of this chapter you should:

Know the different between weatherKnow the different between weatherand climateand climate

Understand what is in the air youUnderstand what is in the air youbreathebreathe

Know how the atmosphere isKnow how the atmosphere islayered above your headlayered above your head

What is What is Meteorology?Meteorology? Aristotle first defined meteorology in Meteorologica

What was a meteor during that period?

He defined a meteor as anything and everything that fell from the sky.

Examples include _________ and _________. rain snow

Now meteorology is the study of its atmosphere and its related phenomena.

Weather and Weather and ClimateClimate

What is weather?

Weather is the condition of the atmosphere at any given time

So a statement of weather would be____________________________.the temperature is 86°F

Another is - the sky was cloudy this morning.

Elements of WeatherElements of Weather

Air temperatureAir temperature

Weather can be described many ways:

Air pressureAir pressure HumidityHumidityCloudsCloudsPrecipitationPrecipitationVisibilityVisibilityWindWind

What Is Climate?What Is Climate? What is climate?

The study of weather over a long period of time

So a statement of climate would be___________________________________.the average temperature for today is 86°F

Another is - San Francisco is usually cloudy in August. Climate deals with averages

“Climate is what you expect, weather is what you get”

Weather and Climate in Weather and Climate in Our LivesOur Lives

Wind chill, cold weatherWind chill, cold weather

Fig. 1-16, p. 19

Weather and Climate in Weather and Climate in Our LivesOur Lives

Crop damage from cold weather, freezeCrop damage from cold weather, freeze

Weather and Climate in Weather and Climate in Our LivesOur Lives

Hot weather, drought, heat strokeHot weather, drought, heat stroke

Weather and Climate in Weather and Climate in Our LivesOur Lives

Hot weather, drought, heat strokeHot weather, drought, heat stroke

Weather and Climate in Weather and Climate in Our LivesOur Lives

Severe thunderstorms, tornadoes, floodingSevere thunderstorms, tornadoes, flooding

Weather and Climate in Weather and Climate in Our LivesOur Lives

Severe thunderstorms, tornadoes, floodingSevere thunderstorms, tornadoes, flooding

Overview of the Overview of the Earth’s Earth’s

AtmosphereAtmosphere

Credit: NASA

Earth’s atmosphere is no thicker than the relative thickness of the skin on an apple.

Composition of the Composition of the AtmosphereAtmosphere

Two category of gases:Two category of gases:

PermanentPermanent

VariableVariable

______ balanced by ____________ balanced by ______Output inputOutput input

Output and input Output and input notnot always balanced in always balanced in time and placetime and place

Example of a Example of a variablevariable gas is gas is ____________.____________.water vaporwater vapor

Table 1-1, p. 3

Source and Removal of Source and Removal of Nitrogen (NNitrogen (N22))

Abundant because mainly Abundant because mainly inertinert Removed by soil Removed by soil bacteria, ocean bacteria, ocean planktonplankton Source is from Source is from decaying plants decaying plants and animals, and animals, volcanoesvolcanoes

Source and Removal of Source and Removal of Oxygen (OOxygen (O22))

Removed when plant and animals decayRemoved when plant and animals decay Removed in chemical processes when Removed in chemical processes when oxygen combines with other stuffoxygen combines with other stuff Removed during Removed during breathingbreathing Source is from Source is from plants during plants during photosynthesis (COphotosynthesis (CO22 + water = sugar and + water = sugar and oxygen)oxygen)

Source and Removal of Water Source and Removal of Water Vapor (HVapor (H22O vapor)O vapor)

Very, very Very, very importantimportant Varies greatly in place and timeVaries greatly in place and time Removed when Removed when

precipitation precipitation falls to surfacefalls to surface

Source is from Source is from evaporation, evaporation, sea windsea wind

Only substance in lower Only substance in lower atmosphere as gas, liquid, atmosphere as gas, liquid, and solidand solid

Source and Removal of Source and Removal of Carbon Dioxide (COCarbon Dioxide (CO22))

Occupies Occupies smallsmall portion of atmosphere portion of atmosphere So what is the big deal? So what is the big deal?

Removed during ______________. Removed during ______________. COCO22 is is stored in roots and branchesstored in roots and branches

Removed by the _______ (massive Removed by the _______ (massive storage - 50 times atmospheric content)storage - 50 times atmospheric content)

photosynthesisphotosynthesis

Source is Source is burning of fossil fuelsburning of fossil fuels (stored (stored COCO22)), , deforestation, vegetation decay, deforestation, vegetation decay, exhalation, volcanoesexhalation, volcanoes

oceansoceans

Past measurements come from ice coresPast measurements come from ice cores

Fig. 1-4, p. 5

Two-faced Ozone (OTwo-faced Ozone (O33))

Largest concentration in the stratosphereLargest concentration in the stratosphere (above 10 km)(above 10 km)

GoodGood in upper atmosphere, absorbs in upper atmosphere, absorbs ultraviolet radiationultraviolet radiation

BadBad near the surface, irritates eyes and near the surface, irritates eyes and throats. Main ingredient of photochemical throats. Main ingredient of photochemical smogsmog

Other Stuff in the AtmosphereOther Stuff in the Atmosphere

AerosolsAerosols• Ash from ________Ash from ________• Salt from wind blown saltwaterSalt from wind blown saltwater• Dust from wind (dust devils)Dust from wind (dust devils)

PollutantsPollutants• Nitrogen dioxide, carbon monoxide, Nitrogen dioxide, carbon monoxide,

hydrocarbons, sulfur dioxidehydrocarbons, sulfur dioxide

Volcanoes

A Changing AtmosphereA Changing Atmosphere

The earliest atmosphereThe earliest atmosphere• Most likely made of of ________ and ________Most likely made of of ________ and ________• So light they escaped to spaceSo light they escaped to space

Subsequent atmosphereSubsequent atmosphere• Volcanoes put gas, outgassing, (water vapor, Volcanoes put gas, outgassing, (water vapor,

COCO22, and some nitrogen) into environment, and some nitrogen) into environment• Water vapor produced rain for thousands of Water vapor produced rain for thousands of

years, COyears, CO22 into into oceansoceans, nitrogen became , nitrogen became abundantabundant

hydrogen helium

How Is the How Is the Atmosphere Atmosphere Structured?Structured?

What is above our heads?What is above our heads?

Air Pressure and Air DensityAir Pressure and Air Density

Air density (_______ per ______)Air density (_______ per ______)• Gravity holds molecules to surface (most dense near Gravity holds molecules to surface (most dense near

surface)surface) Air pressure (______ per ____)Air pressure (______ per ____)

• Always decreases with heightAlways decreases with height• Air pressure changes with changing air densityAir pressure changes with changing air density

Sea-level pressureSea-level pressure• PressurePressure is weight pushing down on your head is weight pushing down on your head• Atmospheric standards (14.7 lbs per square Atmospheric standards (14.7 lbs per square

inch=1013.25 millibars (mb)=29.92 inch Hg)inch=1013.25 millibars (mb)=29.92 inch Hg)

weight volume

force area

Fig. 1-7, p. 8

Fig. 1-8, p. 9

Layers of the AtmosphereLayers of the Atmosphere

TroposphereTroposphere

Temperature generally Temperature generally __________ with height__________ with height

Cools due to ____ heating Cools due to ____ heating surfacesurface

Temperature increasing Temperature increasing with height is called an with height is called an inversioninversion

Contains all weather we Contains all weather we knowknow

decreasessun

StratosphereStratosphere

Is characterized by Is characterized by ____________ air ____________ air temperaturetemperature

Height ofHeight of tropopause tropopause varies varies in heightin height

Ultraviolet light is absorbed Ultraviolet light is absorbed in the stratosphere, in the stratosphere, ________ the layer________ the layer

increasing

warming

MesosphereMesosphere Temperature _____________ Temperature _____________

rapidly once againrapidly once again

Air very thinAir very thindecreasing

ThermosphereThermosphere

Just a small amount of Just a small amount of absorption leads to warmingabsorption leads to warming

Warmer than troposphere, Warmer than troposphere, but you would still freeze to but you would still freeze to death in itdeath in it

The IonosphereThe Ionosphere

Electrified regions of the atmosphereElectrified regions of the atmosphere D, E, and F regionsD, E, and F regions

D region is efficient at absorbing AM radio D region is efficient at absorbing AM radio waves, thus these waves don’t travel very farwaves, thus these waves don’t travel very far

But, at night, the D region dissipates, allowing But, at night, the D region dissipates, allowing for AM waves to bounce off the E and F for AM waves to bounce off the E and F regionsregions

Fig. 1-11, p. 13