Guest Voices: An Unparalleled Record of Earth from Above

Our guest post today comes to us from Jeannie Allen, the Senior Technical Specialist for Sigma Space Corporation at NASA Goddard Space Flight Center. Marking a huge moment, just this past week, NASA has officially handed over the recently launched Landsat Data Continuity Mission (LDCM) satellite to the U.S. Geological Survey (USGS), making the satellite officially Landsat 8.

The transfer marks a major achievement for the historic Landsat program.  Landsat 8 will send back images more useful, detailed, and clear than ever before!

LandsatEarthDay2012_77Visitors to the Smithsonian Mall explore a Landsat scene of Washington DC on Earth Day 2012 (photo credit – Jeannette Allen)

Speeding around the Earth at 16,800 mph (27,000 kph), two Landsat satellites are quietly, faithfully monitoring our dynamic lands from space. Landsat 7 and Landsat 8 are now in orbit about 400 miles above us. Their predecessors began recording specialized digital images of Earth in 1972, creating a treasure trove of information for everyone around the world.

Landsat satellites show us our own landscapes in new ways. With super-human detectors, they see different wavelengths of visible and infrared light reflected and emitted from Earth’s surface. They give us this view at a resolution of 30 m, about the size of a baseball diamond. You can’t see yourself in a Landsat scene, but you can see your neighborhood:  the larger streets, shopping centers, and open spaces.

Mike & Peter_FieldPeople work in the field to confirm the information they get from satellites. (photo credit – Jeannette Allen)

LDCM_still_Gulf_Coast_side_viewJointly managed by NASA and the U.S. Geological Survey, Landsat offers the longest continuous global record of the Earth’s surface as observed from space.  All Landsat data are available at no cost for anyone in the world to download and use. (photo credit – NASA/Goddard Space Flight Center)

What do these satellite scenes tell us about our relationship with the Earth? They tell us we are changing it. Slowly, surely, one piece of ground at a time, we are altering the surface of our planet. You can see these changes in pairs or series of Landsat scenes. People make cities bigger; farmers plant crops, irrigate, and harvest them; forests burn and sprout up again. Glaciers are shrinking in response to a warming climate. The space-based perspective on the changes we’ve made can be surprising!

Picture 2Yellowstone National Park before (1987), during (1988) and after (2011) a huge fire. White puffy clouds appear in some parts of the 1987 image, and gray-blue smoke appears in 1988. Red in the 1988 image indicates areas that are burning or have just burned, detected by Landsat’s sensitivity to infrared light. Pinkish colors in the 2011 image show areas recovering from the fire.

Many scientists, engineers, mathematicians, and their support staff feel strongly about the Landsat satellites. Landsat data provide the backbone for research and practical uses of remote sensing data around the world. Furthermore the data are free. Anyone on the internet can access the data, download it, and explore your own landscape of interest, from USGS GloVIS website.

We can find art as well as science in Landsat scenes. Some people at USGS made a collection of images just for their special qualities of color, composition and form. Earth as Art images are available for download here.

lena_hires

Lena River Delta

malaspina

Malaspina Glacier

FI_EvergladesFlorida Everglades

 To learn more about Landsat, go to:

http://landsat.usgs.gov

http://www.nasa.gov/landsat

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