The atmosphere is a life-giving blanket of air that

surrounds our Earth; it is composed of gases that

protect us from the Sun’s intense heat and ultraviolet

radiation, allowing life to flourish. Greenhouse gases

like carbon dioxide, ozone, and methane are steadily

increasing from year to year. These gases trap heat

radiating from Earth’s surface, causing the

atmosphere to warm. Conversely, aerosols in the air

such as dust, smoke, and ash reflect the Sun’s

radiative energy, which leads to cooling. This delicate

balance of incoming solar radiation and reflected

energy is critical to sustaining life on Earth.

The atmosphere is a life-giving blanket of air that

surrounds our Earth; it is composed of gases that

protect us from the Sun’s intense heat and ultraviolet

radiation, allowing life to flourish. Greenhouse gases

like carbon dioxide, ozone, and methane are steadily

increasing from year to year. These gases trap heat

radiating from Earth’s surface, causing the

atmosphere to warm. Conversely, aerosols in the air

such as dust, smoke, and ash reflect the Sun’s

radiative energy, which leads to cooling. This delicate

balance of incoming solar radiation and reflected

energy is critical to sustaining life on Earth.

Research using computer models and satellite data from

NASA’s Earth Observing System enhances our

understanding of the physical processes affecting trends

in temperature, humidity, and clouds, and helps us

assess the impact of a changing atmosphere on the

global climate.

Research using computer models and satellite data from

NASA’s Earth Observing System enhances our

understanding of the physical processes affecting trends

in temperature, humidity, and clouds, and helps us

assess the impact of a changing atmosphere on the

global climate.

This true-color image of the Earth is,

in fact, not a photograph as we

know it. It was created using

several different data products

derived from the Moderate

Resolution Imaging

Spectroradiometer (MODIS) aboard

NASA’s Terra satellite. These data

are gathered over the entire globe

every day and then composited over

8-, 16-, and 30-day periods to

provide information on such areas of

study as land, ocean, and

atmospheric processes.

Image created by Reto Stockli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA/GSFC, using data from the MODIS Science Team and NOAA

The Earth From SpaceThe Earth From Space

The image above shows emitted longwave radiation escaping the top of Earth’s atmosphere as measured by the

Clouds and the Earth’s Radiant Energy System (CERES ) instrument on May 25, 2001. Record-breaking heat waves

in southern Asia, northern Africa, and southwestern U.S. killed dozens of people during the month of May as seen in

the yellow areas denoting large amounts of thermal energy escaping into space. CERES data are being used to

accurately predict this emission of thermal energy as our world experiences changes in surface reflectivity, clouds,

atmospheric temperatures, and key greenhouse gases.

Image credit: CERES Science Team, NASA Langley Research Center

Anatomy of a Heat WaveAnatomy of a Heat Wave

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Carbon monoxide (CO) is a colorless, odorless, toxic gas. CO reduces the oxygen-carrying capacity of blood in the

body and in day-to-day life can impair mental abilities, especially for those with heart and respiratory conditions.

Its production is a direct result of combustion caused predominantly by industrial processes and biomass burning.

Carbon monoxide levels have been increasing in the atmosphere. In this global image of carbon monoxide from

March 13-15, 2000, lavender indicates high CO values and blues indicate low values. The high concentrations of CO

in west central Africa are largely due to widespread biomass burning.

Image credit: Scientific Visualization Studio, NASA/GSFC, using data from the MOPITT Science Team

Carbon MonoxideCarbon Monoxide

These images are a collection of Multi-

angle Imaging SpectroRadiometer (MISR)

data acquired over eastern Angola and

northeastern Namibia on August 30, 2000.

MISR has nine cameras that focus at

different angles. The panel on the left is a

true color composite from the vertical-

viewing (nadir) camera. The second panel

is a true color composite from the

backward-viewing 70° camera. This angle

enhances the appearance of smoke in the

atmosphere and highlights the presence of

many individual smoke plumes. Retrieved

aerosol amounts are given in the panel on

the right. The images are roughly 380

kilometers (236 miles) in width.

Image credit: MISR Science Team, Jet Propulsion Laboratory

Smoke and Haze Over Southern AfricaSmoke and Haze Over Southern Africa

Nadir 70˚ BackwardAerosol Optical

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Stratospheric ozone protects all life forms

from the sun’s harmful ultraviolet

radiation. These images from the Total

Ozone Mapping Spectrometer (TOMS)

show the progressive depletion of

stratospheric ozone over Antarctica from

1983 to 1997. High concentrations of

ozone are shown in red, low

concentrations in blue.

The Antarctic ozone hole develops each

year between late August and early

October. By September, 1998 it had

grown to cover 10.5 million square miles.

Scientists hope to see a reduction in

ozone loss as emissions of ozone-

destroying CFCs (chlorofluorocarbons)

are reduced.

Image credit: Greg Shirah, NASA/GSFC Scientific Visualization Studio

Ozone DepletionOzone Depletion

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This is an animation of the

stratospheric ozone hole over

Antarctica, as measured by Earth

Probe TOMS from July 15, 2001

through October 9, 2001. Red and

yellow denote regions of high

ozone and dark blue denotes

regions of low ozone.

Animation credit: Greg Shirah, NASA/GSFC Scientific Visualization Studio

Ozone DepletionOzone Depletion

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The troposphere is the lowest layer of the

Earth’s atmosphere, extending to a height of

8-15 kilometers (about 5-9 miles), depending

on latitude. The stratosphere, warmer than

the upper troposphere, is the next layer and

rises to a height of about 50 kilometers

(about 31 miles). Temperatures in the

mesosphere, 50 to 80 kilometers (31 to 50

miles) above the Earth, decline with altitude

to -70° to -140°C (-94° to -220°F), depending

upon latitude and season. Temperatures

increase again with altitude in the

thermosphere, which begins about 80

kilometers (50 miles) above the Earth. They

can rise to 2,000°C (about 3600°F). The

exosphere begins at 500 to 1,000 kilometers

(about 310-621 miles) and the few particles

of gas there can reach 2,500°C (about

4500°F) during the day.

Layers of the AtmosphereLayers of the Atmosphere

The Earth’s surface is kept warm

through one source: the Sun. It is the

primary source for Earth’s energy.

Some of the incoming sunlight and

heat energy is reflected back into

space by the Earth’s surface, gases in

the atmosphere, and clouds; some of

it is absorbed and stored as heat.

When the surface and atmosphere

warm, they emit heat, or thermal

energy, into space. The “radiation

budget” is an accounting of these

energy flows. If the radiation budget

is in balance, then Earth should be

neither warming nor cooling, on

average.

Clouds, atmospheric water vapor and

aerosol particles play important roles

in determining global climate through

their absorption, reflection, and

emission of solar and thermal energy.

Earth’s Radiation ComponentsEarth’s Radiation Components

What types of clouds have you seen in

the sky? They come in four types:

High clouds consisting of cirrus,

cirrostratus and cirrocumulus; middle

clouds consisting of altostratus and

altocumulus; and low clouds

consisting of cumulus, stratocumulus,

nimbostratus and cumulonimbus.

The study of clouds, how they form,

and their characteristics, may well be

a central key to understanding climate

change. Low thick clouds primarily

reflect solar radiation and cool the

surface of the Earth. High, thin clouds

primarily transmit incoming solar

radiation; at the same time, they trap

some of the outgoing infrared

radiation emitted by the Earth and

radiate it back downward, thereby

warming the surface of the Earth.

Cloud Types - ExamplesCloud Types - Examples

This chart represents atmospheric

carbon dioxide (CO2) monthly mean

mixing ratios determined from the

continuous monitoring programs at

three NOAA Climate Monitoring and

Diagnostics Laboratory baseline

observatories: the South Pole, Mauna

Loa, Hawaii, and Barrow, Alaska.

Atmospheric CO2, a major greenhouse

gas, has increased approximately 40

ppmv since 1958, largely because of

human activities. The “zig-zag,” up-

and-down motion of the graph

represents seasonal cycles due to

photosynthetic activity (the

processing of CO2 by vegetation).

The potential effect of the increase in

atmospheric CO2 levels, as well as

other greenhouse gases such as

methane, is a major focus of NASA’s

Earth Science Enterprise.

Carbon Dioxide LevelsCarbon Dioxide Levels

According to researchers at the NASA Goddard Institute for Space Studies, who analyze data collected from several thousand meteorological stations around the world, there has been a long-term global warming trend underway since the early 1960s, with 1998 being the warmest year in the period of satellite instrumental data. The 1999 data show a continuation of that warming trend. The Temperature Index chart combines sea surface temperature measurements from satellites with land surface air temperature measurements from meteorological stations to produce a more truly global land-ocean temperature index than land stations alone could provide.

Data source: Hansen, J. et al., J. Geophys. Res., 104, 30,997-31,022 (1999); NASA Goddard Institute for Space Studies

Global TemperaturesGlobal Temperatures

As demonstrated in these two charts, data from tiny air bubbles trapped in an Antarctic ice core show that atmospheric CO2 concentrations and temperatures from 160,000 years ago to pre-industrial times are closely

correlated. Recent measurements of CO2 concentration and temperature extend this record to the present

day, and confirm that CO2 concentrations have risen to 360 parts per million by volume (ppmv) and

temperatures have increased 0.6°C (1.1°F) over the last 100 years.

Data sources: Ice core data from Barnola, J. M. et al., Nature, 329, 408-414 (1987); current data from the Carbon Dioxide Information Analysis Center, 1997, Oak Ridge, TN

Global TemperaturesGlobal Temperatures

Introduce major concepts of “Air – Our Atmosphere” by dividing

the class into small teams to research several of the questions

on the next page. Students can research their answers using

these slides and other sources. Students can prepare

presentations to cooperatively instruct other teams using pre-

established teacher criteria.

Introduce major concepts of “Air – Our Atmosphere” by dividing

the class into small teams to research several of the questions

on the next page. Students can research their answers using

these slides and other sources. Students can prepare

presentations to cooperatively instruct other teams using pre-

established teacher criteria.

For the Classroom…For the Classroom…

• Why is the study of our atmosphere important?

• Why is NASA involved in the study of atmospheric processes?

• What is haze and how does it affect incoming solar radiation in the atmosphere?

• What can cause haze?

• Make a list of the greenhouse gases. Why are they called greenhouse gases?

• How does each cloud type affect the radiation balance of the Earth?

• Explain the formation and destruction of stratospheric ozone and its effects on people?

• What effect can you have on our atmosphere?

• Why is the study of our atmosphere important?

• Why is NASA involved in the study of atmospheric processes?

• What is haze and how does it affect incoming solar radiation in the atmosphere?

• What can cause haze?

• Make a list of the greenhouse gases. Why are they called greenhouse gases?

• How does each cloud type affect the radiation balance of the Earth?

• Explain the formation and destruction of stratospheric ozone and its effects on people?

• What effect can you have on our atmosphere?

For the Classroom…For the Classroom…