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VIIRS RGB Imagery Renate Brummer WMO-EUMETSAT R G B Satellite Products Workshop 17-19 Sept 2012

VIIRS RGB Imagery Renate Brummer WMO-EUMETSAT R G B Satellite Products Workshop 17-19 Sept 2012. CIRA RGB Team. Curtis Seaman, Steve Miller, Louie Grasso, Renate Brummer Colorado State University/CIRA Don Hillger , John Knaff, Dan Lindsey NOAA/NESDIS/StAR/RAMMB. R G B Basics.

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VIIRS RGB Imagery Renate Brummer WMO-EUMETSAT R G B Satellite Products Workshop 17-19 Sept 2012

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  1. VIIRS RGB ImageryRenate BrummerWMO-EUMETSAT RGB Satellite Products Workshop17-19 Sept 2012

  2. CIRA RGB Team Curtis Seaman, Steve Miller, Louie Grasso, Renate Brummer Colorado State University/CIRA Don Hillger, John Knaff, Dan Lindsey NOAA/NESDIS/StAR/RAMMB

  3. RGB Basics • Every color on a computer monitor may be expressed as 1-byte values of red, green and blue (0-255) • RGB composites take three different values (channels or channel differences, for example), scale them from 0-255 and assign them to red, green or blue • Thus, three different (normally B&W) images are combined to produce one color image

  4. M-05 (0.672 µm) BLUE M-07 (0.865 µm) GREEN M-10 (1.61 µm) RED Example: Take VIIRS channels M-05, M-07 and M-10 reflectances (on a scale from 0-1), scale them from 0-255, then assign them to blue, green and red as above. When you combine them into a single image, you get more information than any single channel can provide…

  5. VIIRS natural color RGB composite image of Greenland and Iceland (13 July 2012) made from M-5 (0.672 µm), M-7 (0.865 µm) and M-10 (1.61 µm). Snow and ice have high reflectance in M-5 and M-7, but absorb M-10: high values of green and blue but low values of red give cyan. Liquid clouds have high reflectance in each channel, so they appear white. Vegetation shows up green. Bare ground shows up brown. Large bodies of water are nearly black. Islands that don’t show up easily in M-7 Clouds that show up easily in M-10, but not M-5 or M-7

  6. “True Color” with no atmospheric correction VIIRS true color and natural color RGB composites of Hawaii (19 February 2012) “True color” composites use radiances/reflectances from the red, green and blue portions of the visible spectrum. On VIIRS, this means channels M-3 (0.488 µm), M-4 (0.555 µm) and M-5 (0.672 µm). Compare the true color image with the “natural color” image of the island of Hawaii after snow fell on Mauna Loa and Mauna Kea. The true color image more closely represents what an astronaut would see from the International Space Station – the “true color” of the objects. The natural color image easily distinguishes liquid clouds from ice clouds, and from snow and ice on the ground. The natural color image is more sensitive to changes in vegetation, less sensitive to aerosols and smoke... “Natural Color” with no atmospheric correction

  7. “True Color” channels M-3 (0.488 µm), M-4 (0.555 µm) and M-5 (0.672 µm) of fires in Siberia, 8 August 2012 (no atmospheric correction) Smoke Smoke Lena River Burn scars

  8. Smoke Smoke Lena River Burn scars “Natural Color” M-5 (0.672 µm), M-7 (0.865 µm) and M-10 (1.61 µm)of fires in Siberia, 8 August 2012

  9. “Natural Color” ” I-1 (0.64 µm), I-2 (0.87 µm), I-3 (1.61 µm) of Michigan, 10 June 2012 Duck Lake Fire burn scar Iron mine Limestone quarry Sleeping Bear Dunes The high resolution natural color composite of channels I-01, I-02 and I-03 is quite sensitive to the amount (and health) of the vegetationand therfore useful in highlighting the burn area.

  10. “True Color” M-3 (0.488 µm), M-4 (0.555 µm) and M-5 (0.672 µm) of Michigan, 10 June 2012 Duck Lake Fire burn scar Iron mine Limestone quarry Sleeping Bear Dunes

  11. In the true color RGB, the iron mine stands out as a bright red. Why? The true color composite uses wavelengths at 0.48 µm (blue), 0.55 µm (green) and 0.67 µm (red). The red channel in the true color composite is actually in the red portion of the visible spectrum. The blue channel in the false color composite (0.64 µm) is also in the red portion of the visible spectrum. This example shows that the iron oxide (rust) produced at the iron mine is highly reflective in the red portion of the visible spectrum. That’s what gives it the characteristic rust color. Iron oxide is not nearly as reflective at shorter or longer wavelengths, so it shows up blue when red wavelengths are used as the blue channel (as in the false color composite) and red when they are used as the red channel (as in the true color composite). Let this be a lesson to anyone who uses the false color composite as part of a snow and ice detection algorithm. Snow and ice are not the only things to show up that color. You may be looking at a really large iron mine.

  12. “Natural Color” I-1 (0.64 µm), I-2 (0.87 µm), I-3 (1.61 µm) of Easter Island, 26 April 2012

  13. Cap Verde “Natural Color” I-1 (0.64 µm), I-2 (0.87 µm), I-3 (1.61 µm) of Cape Verde, 5 June 2012

  14. “Natural Color” I-1, I-2, I-3 of Louisiana/Gulf Coast, 26 August 2012 Before Hurricane Isaac

  15. “Natural Color” I-1, I-2, I-3 of Louisiana/Gulf Coast, 1 September 2012 After Hurricane Isaac Highlighted areas are where significant flooding occurred

  16. Dust Storm in Texas February 2012 20 Feb 2012: Photograph of dirt blowing across a road causing low visibility near Brownfield (photo courtesy Bill Hopkins).

  17. 20 February 2012 NPP VIIRS 1940 UTC Lubbock, TX US 84 between Southland and Post, TX (~20 miles SE of Lubbock) 63 mph winds, 50 ft visibility, 30 vehicles, 2 fatalities

  18. VIIRS true-color imagery (center-half of granule) VIIRS true-color image from bands M5/M4/M3 (750 m) on 13 August 2012 @ 1312 UTC over Strait of Gibraltar (processed on McIDAS-X) Several processing steps: 1) Capture M5/M4/M3 granules, 2) Fill bowtie deletions at each end of granule, 3) Rotate image (for ascending orbits), 4) Rayleigh (atmospheric) correction, 5) Square-root scaling (to highlight darker features), 6) Combine as RGB.

  19. VIIRS true-color imagery (center-half of granule) VIIRS true-color image from bands M5/M4/M3 (750 m) on 8 August 2012 @ 1807 UTC over Bahamas (processed on McIDAS-X) Several processing steps: 1) Capture M5/M4/M3 granules, 2) Fill bowtie deletions at each end of granule, 3) Rayleigh (atmospheric) correction, 4) Rotate image (for ascending orbits), 5) Square-root scaling (to highlight darker features), 6) Combine as RGB.

  20. China Nepal Bhutan India Bangladesh VIIRS true-color image from bands M5/M4/M3 over northern India and Tibet, with a large contrast in aerosol scattering between the cooler and drier and shallower air mass to the north of the Himalayan chain and the warm and humid and deeper air mass to the south.

  21. Uses of VIIRS RGB composites • A few examples have been shown of the uses of RGB composites of VIIRS channels, including: • Identifying cloud phase • Separating snow/ice from low clouds • Vegetation health • Fire detection • Flood monitoring • Producing amazing imagery

  22. RGB Fire Products

  23. Fires in Siberia near Yakutskthe “Coldest City on Earth” Yakutsk is the capital city of the Sakha Republic which, according to Wikipedia, is the largest sub-national governing body in the world (only slightly smaller than India in terms of land area). Over 260,000 people live in Yakutsk, which has been called the “Coldest City on Earth” . In January, the average temperature is -42 °C (-45 °F), and it isn’t very far from Oymyakon , where the lowest temperature ever recorded in a permanently inhabited location was observed (-71.2 °C or -96.2 °F). In the summer, it can make it up to +35 °C (95 °F) and legends tell of reindeer dying from choking on all the insects that cloud the air. 4 - 7 August 2012

  24. VIIRS Visible image of fires in Siberia – Band M5 (0.672 µm) Visible image of fires in Siberia from VIIRS channel M-5, taken 02:38 UTC 4 August 2012 Except for a few clouds near the edges of the scene, that is pretty much all smoke.

  25. VIIRS DNB image of fires in Siberia - 16:25 UTC 4 August 2012 At this latitude, longitude lines are ~55 km apart. The latitude lines are ~111 km apart. So, you can see that these fires cover quite a large area. Yakutsk, which is underneath the clouds (and possibly smoke) at about 62° N, 130° E.

  26. “True Color” M-3, M-4, M-5 of fires in Siberia, 8 August 2012 (no atmospheric correction) Smoke Smoke Lena River Burn scars

  27. “Natural Color” M-5, M-7, M-10 of fires in Siberia, 8 August 2012 Smoke Smoke Lena River Burn scars

  28. False Color M-5, M-7, M-11 of fires in Siberia, 8 August 2012 Smoke Smoke Lena River Use of M-11 (2.25 µm) in place of M-10 enhances detection of pixels with actively burning fires. These pixels show up as red. Burn scars

  29. SIBERIA M-10 (1.61 mm) M-11 (2.25 mm) M-12 (3.70 mm) 7 August 2012 03:22 UTC

  30. Fires on the Canary Islands July / August 2012 The Spanish Canary Islands have been under a drought, as has much of Spain. In July, fires started to burn on Tenerife, and in early August, fires began burning on La Palma and La Gomera.

  31. Canary Islands - 14:01 UTC 5 August 2012 VIIRS “true color” image (M-3 [0.488 µm], M-4 [0.555 µm], M-5 [0.672 µm]) . Smoke plumes are coming off of La Palma and La Gomera .

  32. Canary Islands - 14:01 UTC 5 August 2012 VIIRS false color RGB composite of channels: true color RGB composite is better for viewing the smoke plume, but you can’t actually see the fire directly. So, here’s the false color M-5 (0.672 µm), M-7 (1.61 µm) and M-11 (2.25 µm) composite from the same time.

  33. Canary Islands - 14:01 UTC 5 August 2012 Same image as prevoius VIIRS false color RGB composite : Zoom in to make the fires even more obvious:

  34. Fire on La Palma Fire on La Gomera CANARY ISLANDS M-10 (1.61 mm) M-11 (2.25 mm) M-12 (3.70 mm) 5 August 2012 14:01 UTC

  35. Canary Islands - channel I-04 (3.7 µm) 14:01 UTC 5 August 2012 La Gomera has been the hardest hit island, where thousands of people had to be evacuated, and approximately 10% of Garajonay National Park has burned. M-13 (4.0 µm), which is a dual-gain band designed to not saturate, reached a brightness temperature of 451 K over La Gomera, compared with a saturation brightness temperature of 367 K for channel I-04.

  36. Canary Islands -VIIRS Day/Night Band - 02:25 U 02:25 UTC 6 August 2012 VIIRS DNB band ( 0.7 µm, 750 m): The red arrows point out the fires on La Palma and La Gomera. The fire on La Gomera covers a significant percentage of the island. The yellow arrow points to Lanzarote. On the night this image was taken, the moon was approximately 84% full, so you can see a number of clouds as well the city lights from the major resort areas of the Canary Islands.

  37. Colorado Wildfires in VIIRS 26 June 2012

  38. Active and visible Active (not visible) Inactive and visible Inactive (not visible) High Park Woodland Heights Flagstaff Last Chance Treasure Lower North Fork Springer Waldo Canyon Sunrise Mine I-4 (3.7 mm) 19:58 UTC 26 June 2012 Little Sand Weber

  39. Active and visible Active (not visible) Inactive and visible Inactive (not visible) High Park Woodland Heights Flagstaff Last Chance Treasure Lower North Fork Springer Waldo Canyon Sunrise Mine Little Sand Weber RGB 19:58 UTC 26 June 2012 Blue: I-1 (0.64 mm) Green: I-2 (0.86 mm) Red: I-3 (1.61 mm)

  40. High Park Fire COLORADO Little Sand Fire M-10 (1.61 mm) M-11 (2.25 mm) M-12 (3.70 mm) 10 June 2012 19:59 UTC

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