Land ecosystems cover nearly 30% of the Earth’s surface. The land surface changes over days, seasons, decades, and longer. Vegetation boundaries shift,

Land ecosystems cover nearly 30% of the Earth’s surface. The

land surface changes over days, seasons, decades, and longer.

Vegetation boundaries shift, cities grow, rain forests and farm

lands shrink, amounts of trace chemicals in the air increase

and decrease, rivers flood, forests burn, and volcanoes erupt.

Activities of the growing human population cause or influence

many of these changes.

Land ecosystems cover nearly 30% of the Earth’s surface. The

land surface changes over days, seasons, decades, and longer.

Vegetation boundaries shift, cities grow, rain forests and farm

lands shrink, amounts of trace chemicals in the air increase

and decrease, rivers flood, forests burn, and volcanoes erupt.

Activities of the growing human population cause or influence

many of these changes.

Space provides an excellent vantage point from which to

observe and record land surface changes, especially at a global

scale. NASA has embarked on an ambitious program called the

Earth Science Enterprise to measure the effects of changes on

our planet and to understand the roles that human activities

play in them. A suite of Earth-observing satellites looks at

different aspects of the land and builds a global picture of

change, one location at a time.

Space provides an excellent vantage point from which to

observe and record land surface changes, especially at a global

scale. NASA has embarked on an ambitious program called the

Earth Science Enterprise to measure the effects of changes on

our planet and to understand the roles that human activities

play in them. A suite of Earth-observing satellites looks at

different aspects of the land and builds a global picture of

change, one location at a time.

The Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) gives a detailed look at global vegetation patterns on a weekly basis. This image is an EVI image from early October 2000 that shows global vegetation distributions. Vegetation is denser near the equator, but is beginning to fade in the northern latitudes as they move into fall. Vegetation indices are useful for a wide range of scientific and environmental applications, including monitoring changes in the extent of deserts or wetlands, determining where

water stress may be causing habitat loss, and tracking changes in the length of growing seasons.

Image credit: MODIS Land Team/Vegetation Indices, Alfredo Huete, Principal Investigator; Kamel Didan

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Looking at Ecosystems and Vegetation


Enhanced VegetationIndex

This image is an example of a MODIS land cover map. This map contains 17 different land cover types,

differentiating among eleven natural vegetation types such as deciduous and evergreen forests, savannas,

grasslands, and shrublands. High-quality land cover maps greatly aid scientists and policy makers involved in

a wide range of activities from natural resource management, such as land use and resource exploitation, to

research and global monitoring objectives.

Image credit: MODIS Land Cover Product, Alan Strahler, Principal Investigator; Mark Friedl and John Hodges, Boston University



0 Water1 Evergreen Needleleaf Forest2 Evergreen Broadleaf Forest3 Deciduous Needleleaf Forest4 Deciduous Broadleaf Forest5 Mixed Forests6 Closed Shrublands7 Open Shrublands8 Woody Savannas9 Savannas10 Grasslands11 Permanent Wetlands12 Croplands13 Urban and Built-Up14 Cropland/Natural Vegetation Mosaic15 Snow and Ice16 Barren or Sparsely Vegetated

Rapid change occurs as Mt. Etna erupts in

this Advanced Spaceborne Thermal

Emission and Reflection Radiometer

(ASTER) image taken on Sunday, July 29,

2001. Lava flows appear dark purple and

red and yellow indicate areas of highest

temperatures. Bluish smoke drifts across

the scene, and white clouds of volcanic

steam make shadows on the changing land.

Image credit: NASA/GSFC, METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Mount Etna EruptsMount Etna Erupts

Trailblazing firefighters and land

managers now use NASA satellite data

to combat wildfires. This image of the

southeastern coast of Australia on

January 2, 2002, from MODIS onboard

the Terra satellite, shows thick plumes

of grayish smoke streaming eastward

from more than a dozen active fires.

Fires encircle the city of Sydney,

which stands out in tan against the

surrounding green vegetation.

Image credit: Jacques Descloitres, MODIS Land Rapid Response Team at NASA/GSFC

Fighting Fires with Satellite Imagery


In a collaboration between NASA, the

University of Maryland, and the U.S.

Department of Agriculture’s Forest

Service, firefighters receive maps and

satellite images of current active fires,

and use them for strategic planning.

After the fire is controlled, land

managers use the satellite images and

maps for post-fire rehabilitation and

protection of water quality.

This photograph was taken on August

6, 2000 in the Bitterroot National

Forest, Montana, when the forest was

ravaged by wildfires.

Image credit: John McColgan, Fire Behavior Analyst, Alaska Forest Service



A Landsat image (above, left) taken in 1972 and an ASTER image (above, right) taken in 2000 of Riyadh, Saudi Arabia dramatize evidence of an increasing human population. Population increases around the world have caused all sorts of problems, such as air pollution, traffic jams, overextended water resources, overfilled garbage dumps, and the destruction of natural wildlife habitats. Landsat and ASTER images provide important long-term records of urban growth, and can help us make decisions about the most effective use of space and resources for the future.

Landsat image credit: U.S. Geological Survey EROS Data Center and Landsat 7 Science Team

ASTER image credit: NASA/GSFC, METI/ERSDAC/JAROS, U.S./Japan ASTER Science Team

A City in the DesertA City in the Desert

1972 2000

The images on this and the following

two slides are of the Chesapeake Bay

region and Baltimore, Maryland (U.S.)

They showcase the different capabilities

of instruments on Earth-observing

satellites for viewing the land at

different light wavelengths and degrees

of detail.

This true-color MODIS image provides a

regional view of the area at a low 415

meters (about 1361 feet) resolution,

with Baltimore appearing as a white to

light gray area along the northwest edge

of the Chesapeake Bay.

MODIS image credit: Jacques Descloitres, MODIS Land Science Team

Views of the Chesapeake BayViews of the Chesapeake Bay

This Landsat 7 true color view of

Baltimore (Image 2) at 30 meters

(98.4 feet) provides further detail of

the region. Landsat 7 image credit: U.S. Geological Survey EROS Data Center and Landsat 7 Science Team


This ASTER image (Image 3) at 15

meters (49.2 feet) combines near-

infrared, red, and green light to create

a false-color image that depicts

vegetation as red, water as blue, and

urban areas as gray.

ASTER image credit: U.S./Japan ASTER Science Team


Southern California’s dramatic topography

plays a critical role in its climate,

hydrology, ecology, agriculture, and

habitability. This image of Southern

California, from the desert at Mojave to the

ocean at Ventura, shows a variety of

landscapes and environments.

This perspective view was generated by

draping a Landsat satellite image over a

preliminary topographic map, acquired by

the Shuttle Radar Topography Mission

(SRTM) aboard the Space Shuttle

Endeavour in February 2000. It shows the

Tehachapi Mountains in the right

foreground, the city of Ventura on the coast

at the distant left, and the easternmost

Santa Ynez Mountains forming the skyline

at the distant right.

Image credit: NASA/JPL, National Imagery and Mapping Agency

The Mojave DesertThe Mojave Desert

Vegetation on Mount St. Helens is

actively recovering from the massive

eruption on May 18, 1980, as seen in

this image. Landsat 7 acquired the

larger image on August 22, 1999.

Some of the effects of the eruption

can still be seen clearly, especially on

the northern and eastern flanks of the

mountain, which are still mostly

barren (shades of white and light

gray). The crater is in the center of

the image.

Landsat 7 image credit: U.S. Geological Survey EROS Data Center and Landsat 7 Science Team

Mount St. HelensMount St. Helens

This image of Mount St. Helens was

acquired by ASTER on August 8, 2000

and covers an area of 37 by 51

kilometers (about 23 by 32 miles).

Topography has been exaggerated 2

times to enhance the appearance of

the relief.

ASTER image credit: NASA/GSFC, METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Mount St. HelensMount St. Helens

This image, acquired by ASTER on

August 24, 2000, shows the extent of

deforestation in the state of

Rondonia, Brazil. Tropical rainforest

appears red and cleared land appears

light gray.

The Amazon Basin is the largest

continuous region of tropical forest in

the world, containing nearly 31% of

the world’s total. Monitoring global

deforestation here provides critical

information on the Earth as a system,

as plant cover interacts with the air,

soil, and water in many ways.

Image credit: NASA/GSFC, METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Views of DeforestationViews of Deforestation

This image, acquired from Landsat 7 on August 1, 2000, shows how a large agricultural development effort, called the Tierras Baja project, and resettlement of people from the Andean high plains have brought rapid deforestation of the tropical dry forest in Santa Cruz de la Sierra, Bolivia. The radial patterned fields are part of the San Javier resettlement scheme.

Image credit: U.S. Geological Survey EROS Data Center and Landsat 7 Science Team

Views of DeforestationViews of Deforestation

Carbon is key to life, and it moves

throughout the Earth system in a major

biogeochemical cycle. Photosynthesis by

land plants plays an important role in that

cycle. As seen in this illustration, carbon

dioxide from the surrounding air is

absorbed by the tree and converted to

oxygen, which is then released back into

the air during photosynthesis. This process

results in a net removal of carbon dioxide

from the air and its storage in the tissues

of plants. In this way, carbon moves from

one sphere of the Earth system (the air) to

another (the land), where it is temporarily

stored. (Dry wood is about 50% carbon.)

Natural CO2 CycleNatural CO2 Cycle

When forests die and decay or

are burned, large amounts of

plant tissue, known as

biomass, are oxidized, and

carbon dioxide returns to the

air. The burning of tropical

forests has increased

dramatically in recent decades

and currently releases about

10 to 20% as much carbon

dioxide into the atmosphere as

the burning of fossil fuels. The

effects of that increase in

carbon dioxide ripple

throughout the Earth system,

and monitoring these changes

by satellite is essential.

Biomass Burning and CO2Biomass Burning and CO2

Natural resource managers have new tools

for their work with satellite imagery.

About 100 Landsat scenes appear in this

image of Southeast Asia. With satellite

remote sensing and Geographic

Information Systems (GIS) technology,

scientists can accurately measure the rate

of change and extent of tropical

deforestation. With these data, they can

determine the net release from the forest

to the atmosphere of important trace

gases such as carbon dioxide, which

impact climate and other aspects of the

Earth system.

Images credit: Tropical Rain Forest Information Center, Basic Science and Remote Sensing Initiative at Michigan State University (A member of the NASA Federation of Earth Science Information Partners)

Vegetation in Southeast AsiaVegetation in Southeast Asia

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Introduce major concepts of “Land – Our Changing Earth” 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 “Land – Our Changing Earth” 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…

• How does the Earth’s land surface change through time?

• What are some of the ways people change the Earth’s land surface?

• Where is the destruction of forests taking place most rapidly, and why there?

• How might land cover and land use changes affect wildlife and plants?

• What are some of the ways that events and processes taking place on the land surface affect the atmosphere?

• How can people use satellite observations to prevent and fight fires?

• What do Earth-observing satellites show us that can help us decide where and how to live?

• What can satellite images tell us about natural hazards such as volcanoes, fires, floods and drought?

• How does the Earth’s land surface change through time?

• What are some of the ways people change the Earth’s land surface?

• Where is the destruction of forests taking place most rapidly, and why there?

• How might land cover and land use changes affect wildlife and plants?

• What are some of the ways that events and processes taking place on the land surface affect the atmosphere?

• How can people use satellite observations to prevent and fight fires?

• What do Earth-observing satellites show us that can help us decide where and how to live?

• What can satellite images tell us about natural hazards such as volcanoes, fires, floods and drought?

For the Classroom…For the Classroom…

Documents

Land ecosystems cover nearly 30% of the Earth’s surface. The land surface changes over days, seasons, decades, and longer. Vegetation boundaries shift,