 |
|
|
||||
| Earth Resources Observation and Science (EROS) |
|
Tracking Change Over Time: A Classroom Activity
The Earth's surface is constantly changing. Continents shift. Seacoasts erode. Cities grow. Floodwaters cover one region while drought scorches another. It's hard to see these changes from ground level. A much broader view is needed, together with a consistent record of change over time. Satellites that capture images of large areas of the Earth's surface at regular intervals can provide this view. By comparing satellite images from different times, it's possible not only to see changes, but to understand their effects. The below images were taken by Landsat satellites. The images span 30 years and are archived at the Center for Earth Resources Observation and Science (EROS). Satellite images are somewhat different than pictures taken with a camera. Satellite sensors record waves of light and heat energy coming off the Earth's surface. Different sets of these energy waves are called bands. Images are created by putting together several bands (usually three). Various combinations of bands make it possible to see certain types of things in a satellite image that you couldn't see in an ordinary photograph.
Scientists compare images like these in order to learn more
about changes taking place in a region, across the country, and
around the world. Compare the images in each set. What
changes do you see? A detailed classroom activity can be built
around these image sets using either the EROS Earth Images for
Education: Tracking Change Over Time Lesson Plan and CD or
by downloading the images directly from this site. To manipulate the bands on the images, use MultiSpec (freeware), which is available at http://dynamo.ecn.purdue.edu/~biehl/MultiSpec.
Over the past 30 years, the United States Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) has evolved from a handful of people working in a cramped, temporary office in downtown Sioux Falls to a world-class data archive and research facility with roughly 600 employees. The center's founding was linked to the launch of the first Landsat satellite in 1972. Currently Landsat 7 orbits earth from 428 miles up, beaming down images of the planet's surface to the center on a daily basis. In August 1973, the Mundt Federal Building was completed 16 miles northeast of Sioux Falls to house the Center for EROS and its growing archive. That growth continues today. EROS maintains one of the largest collections of remotely sensed images of the Earth’s land surface. Most come from Landsat and other civilian satellites, including weather satellites and NASA’s Terra, Aqua, and EO-1 satellites. The Center also houses an extensive collection of aerial photographs. All told, the archive contains more than 28.5 million remotely sensed images. The total number grows by roughly 9.8 million every year. The EROS staff manages and distributes archived images to scientists, policy makers, and educators worldwide who use them in the study of natural hazards, environmental change, economic development, and conservation issues. Researchers at EROS also use powerful computer systems to process and analyze satellite data in new ways. Every advance enhances our understanding of the Earth, how it changes over time, and the implications of those changes for people and ecosystems worldwide.
For more information contact: |
| AccessibilityFOIAPrivacyPolicies and Notices | |
  |
|
