First Global Image from VIIRS

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    NASA acquired November 24, 2011

    From its vantage 824 kilometers (512 miles) above Earth, the Visible Infrared Imager Radiometer Suite (VIIRS) on the NPOESS Preparatory Project (NPP) satellite gets a complete view of our planet every day. This image from November 24, 2011, is the first complete global image from VIIRS.

    The NPP satellite launched on October 28, 2011, and VIIRS acquired its first measurements on November 21. To date, the images are preliminary, used to gauge the health of the sensor as engineers continue to power it up for full operation.

    Rising from the south and setting in the north on the daylight side of Earth, VIIRS images the surface in long wedges measuring 3,000 kilometers (1,900 miles) across. The swaths from each successive orbit overlap one another, so that at the end of the day, the sensor has a complete view of the globe. The Arctic is missing because it is too dark to view in visible light during the winter.

    The NPP satellite was placed in a Sun-synchronous orbit, a unique path that takes the satellite over the equator at the same local (ground) time in every orbit. So, when NPP flies over Kenya, it is about 1:30 p.m. on the ground. When NPP reaches Gabon—about 3,000 kilometers to the west—on the next orbit, it is close to 1:30 p.m. on the ground. This orbit allows the satellite to maintain the same angle between the Earth and the Sun so that all images have similar lighting.

    The consistent lighting is evident in the daily global image. Stripes of sunlight (sunglint) reflect off the ocean in the same place on the left side of every swath. The consistent angle is important because it allows scientists to compare images from year to year without worrying about extreme changes in shadows and lighting.

    The image also shows a band of haze along the right side of every orbit swath. When light travels through the atmosphere, it bounces off particles or scatters, making the atmosphere look hazy. The scattering effect is most pronounced along the edge of the swath, where the sensor is looking at an angle through more of the atmosphere. Scientists can correct for this scattering effect, but need measurements from a range of wavelengths to do so. The degree to which light scatters depends partly on the wavelength of the light. Blue light scatters more than red light, for example, which is why the sky is blue. VIIRS measures 22 different wavelengths of light, but not all of the sensor’s detectors are operating at peak performance yet. Those measuring thermal infrared light are not yet cold enough to collect reliable measurements.

    Once VIIRS begins full operations, it will produce a range of measurements from ocean temperature to clouds to the locations of fires. These measurements will help extend the record from earlier sensors like the Moderate Resolution Imaging Spectroradiometer (MODIS). VIIRS is very similar to MODIS, but flies at a higher altitude to measure the whole planet without gaps. (MODIS daily measurements have gaps at the equator. See the MODIS image from November 24.) VIIRS also sees the Earth in less detail, 375 meters per pixel, compared to 250 meters per pixel for MODIS.

    Image by NASA’s NPP Land Product Evaluation and Testing Element. Caption by Holli Riebeek.

    Credit: NASA Earth Observatory

    NASA image use policy.

    NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.

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    J&S., mattdupont, DimitraTzanos, and 41 other people added this photo to their favorites.

    1. ♫ Lion ♫ 29 months ago | reply

      Wow interesting!

    2. dodagp 29 months ago | reply

      Captivating !!!

    3. mothernature photography 29 months ago | reply

      Outstanding, and oh my look how Antarctica seems to dominate in size and weather patterns. Out of sight often and out of mind but so very important to us all.

    4. dreamer@desh 29 months ago | reply

      what a picture!

    5. jaffles 28 months ago | reply

      What a beautiful shot!

    6. brensukend [deleted] 28 months ago | reply

      wow...another advancement for ...you...first time ive heard of..these ....is it npoess..or pois?....

    7. DigitalLyte 27 months ago | reply

      fascinating and wonderfully beautiful

    8. RinkRatz 27 months ago | reply

      World English Bible, Genesis 1

      1 In the beginning God {After "God," the Hebrew has the two letters "Aleph Tav" (the first and last letters of the Hebrew alphabet) as a grammatical marker.} created the heavens and the earth.

      2 Now the earth was formless and empty. Darkness was on the surface of the deep. God's Spirit was hovering over the surface of the waters.

      3 God said, "Let there be light," and there was light.

      4 God saw the light, and saw that it was good. God divided the light from the darkness.

      5 God called the light Day, and the darkness he called Night. There was evening and there was morning, one day.

      6 God said, "Let there be an expanse in the middle of the waters, and let it divide the waters from the waters."

      7 God made the expanse, and divided the waters which were under the expanse from the waters which were above the expanse; and it was so.

      8 God called the expanse sky. There was evening and there was morning, a second day.

      9 God said, "Let the waters under the sky be gathered together to one place, and let the dry land appear;" and it was so.

      10 God called the dry land Earth, and the gathering together of the waters he called Seas. God saw that it was good.

      11 God said, "Let the earth put forth grass, herbs yielding seed, and fruit trees bearing fruit after their kind, with its seed in it, on the earth;" and it was so.

      12 The earth brought forth grass, herbs yielding seed after their kind, and trees bearing fruit, with its seed in it, after their kind; and God saw that it was good.

      13 There was evening and there was morning, a third day.

      14 God said, "Let there be lights in the expanse of sky to divide the day from the night; and let them be for signs, and for seasons, and for days and years;

      15 and let them be for lights in the expanse of sky to give light on the earth;" and it was so.

      16 God made the two great lights: the greater light to rule the day, and the lesser light to rule the night. He also made the stars.

      17 God set them in the expanse of sky to give light to the earth,

      18 and to rule over the day and over the night, and to divide the light from the darkness. God saw that it was good.

      19 There was evening and there was morning, a fourth day.

    9. twiga269 ॐ FEMEN 27 months ago | reply

      Fascinating picture(s) !!

    10. Alejandro Martin Ines 16 months ago | reply

      Are there another projections using this lovely map?

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