Daily Starter

1. What has more mass:

– one pound of air or one pound of gold– Explain your answer

2. True or false – Water boils at the same temperature in all locations on Earth.

Atmosphere

Chapter 11

What is the atmosphere?

A thin layer of air that protects the A thin layer of air that protects the Earth’s surface from extreme temperatures Earth’s surface from extreme temperatures and harmful Sun rays.and harmful Sun rays.

Structure of the atmosphere

• The atmosphere is made of different layers, each of which has different temperatures and different chemicals compositions

The lower atmosphere (Earth’s surface to

50km high) • Troposphere (Earth’s surface to 9-16km)• Where we live• Contains most of the mass of the atmosphere• Contains most of the water vapor• Most of the weather takes place in the troposphere• Most of the atmospheric pollution is found in the

troposphere• Temperature decreases from the bottom to the top• The upper limit is called the tropopause

The lower atmosphere (Earth’s surface to

50km high) • Stratosphere (9-16km to 50km)

• Made up primarily of O3 which absorbs UV

radiation• Air temperature increases from the bottom of the

stratosphere to the top• The top layer is called the stratopause

The Upper Atmosphere (50km to >500km)

• Mesosphere (50km to 100km)

• No more O3 found here

• Temperature decrease from the bottom to the top

• Shooting stars occur here

• The upper limit is the mesopause

The Upper Atmosphere (50km to >500km)

• Thermosphere (100km to 500km)

• Very small mass of the atmosphere

• The temperature increases from the bottom to the top

• The ionosphere is part of the thermosphere and is made of electrically charged particles

• Radio-waves are carried in the ionosphere

The Upper Atmosphere (50km to >500km)

Exosphere (>500km)

Quickly moving hydrogen

and helium molecules

How do we know the Temperature?The radiosonde is a balloon-borne instrument

platform with radio transmitting capabilities. It is a combination of the words "radio" for the onboard radio transmitter and "sonde", which is messenger

from old English. The radiosonde contains instruments capable of

making direct in-situ measurements of air temperature, humidity and pressure with height, typically to altitudes of approximately 30 km. These

observed data are transmitted immediately to the ground station by a radio transmitter located within

the instrument package.

How it all layers out

What is the atmosphere?• Mixture of gases• Approximately 99% is oxygen and

nitrogen• Both are critical for life on this planet• Remaining 1% is a mixture of other

gasesArgonNeon

HydrogenCarbon dioxide (less than 1%)

Water vapor (up to ~4%)• Goes from the earth’s surface to outer

space

• Water vapor and carbon dioxide are extremely important in the way our atmosphere affects weather

• The combination of the two gases affects how much energy the atmosphere will absorb

Water Vapor and Carbon Dioxide

•Varies by season, altitude and what is below the air

•Source of precipitations

•Water exists in all three stages in the atmosphere

•When water changes between states it will absorb or release energy in the form of heat

•This heat exchange affects the movement of the atmosphere

Water Vapor

Variable Components

• Aerosols are tiny solid and liquid particles in the atmosphere (e.g., smoke and soot from wild fires or ash from volcanic eruptions).

• Ozone is a form of oxygen that combines three oxygen atoms into a molecule. Ozone absorbs potentially harmful ultraviolet (UV) radiation from the Sun.

Ozone (O3)

• Oxygen molecule with a third oxygen atom attached

• Exists in small quantities in the stratosphere

• O3 absorbs UV radiation

• Protects humans from burning

• The ozone layer has gone through changes in recent geologic time

Ozone Layer

– Life on Earth, as we know it, depends on it.– Pollutants called chlorofluorocarbons (CFCs)

are destroying the ozone layer.• CFCs are used in refrigerators, air conditioners,

aerosol sprays, and foam packaging.

• If these products develop a leak, CFCs can enter the atmosphere.

– The ozone layer has a large hole over Antarctica and a smaller one over the north pole.

The Sun

• The sun is the sole source of all energy to the atmosphere

• The energy is transferred in three ways:– Radiation– Conduction– Convection

Method one: Radiation

•Transfer of energy through visible, ultraviolet, and other forms of electromagnetic waves

•All objects that have a temperature above absolute zero (-273 Celsius or

-523 Fahrenheit) emit radiation

Radiation

•The earth both absorbs energy (heat) and emits it

•50% of all incoming radiation is absorbed by the earth’s surface

•15% is absorbed by the atmosphere

•35% is reflected back into space

Scattering by Aerosols

Clouds with low aerosol concentration

and a few large droplets do not scatter

light well, and allow much of the Sun's light

to pass through and reach the surface.

Scattering by Aerosols

The high aerosol concentrations in these

clouds provide the nucleation points necessary for the

formation of many small liquid water droplets. Up

to 90% of visible radiation (light) is

reflected back to space by such clouds without

reaching Earth's surface.

(Global Dimming!!!)

Radiation

• The structure of the earth’s surface affects the absorption of the incoming radiation

• Water heats up and cools off slowly• Darker objects heat up more quickly

than lighter colored objects• Overall the earth reflects and absorbs

equal amounts of energy

Method Two: Conduction • Transfer of energy when

molecules collide• Warm earth surface has quick

moving molecules; these molecules collide with the slow moving molecules of the cooler surface air

• The energy/heat from the earth surface warms the atmosphere close to the ground

• Conduction only warms the lowest portion of the atmosphere

Method Three: Convection • The transfer of energy by the flow of a heated substance• Once the heat is transferred into the lower atmosphere it

can be moved up into the atmosphere via convection• As the air is heated it becomes less dense and will rise• As it rises it cools and becomes denser and then it sinks• These movements are called convection currents

(vertical)• These convection currents cause weather!!!!!!!!