GOES visible, 10.7 µm IR, 3.9 µm IR, and 6.5 µm water vapor images, displayed using AWIPS II

CIMSS has recently begun the process of evaluating and testing satellite imagery and products in the next generation of AWIPS (AWIPS II or AWIPS Migration). GOES 0.65 µm visible channel, 10.7 µm IR channel, 3.9 µm IR channel, and 6.5 µm water vapor channel data from 15 April 2010 are displayed using the Common AWIPS Visualization Environment (CAVE) component of AWIPS II (above). Some features of interest include areas of showers and thunderstorms in parts of Texas and far eastern New Mexico, the large gradient of water temperatures over the far western Atlantic Ocean, and a large area of snow cover in southern Alberta, Canada.

A closer view of the snow cover using GOES 0.65 µm visible channel data (below) shows the areal coverage of the heavy snow that fell on 14 April. Some areas in southeastern Alberta received as much as 60 cm (24 inches) of heavy, wet snowfall which led to widespread power outages and some road closures. The edges of the snow cover can be seen to be melting inward, a testament to the heating power of the higher sun angle of mid-April.

GOES 0.65 µm visible images, displayed using AWIPS II

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Animation of rooftop camera images from the University of Wisconsin - Madison / AOS / SSEC building (looking west)

The break-up of a meteor entering the Earth’s atmosphere caused a large “fireball” of light that was seen  across parts of the Upper Midwest region around 10:00 pm local time on 14 April 2010 (or 03:00 UTC on 15 April 2010). The images above — also available as a QuickTime animation — were taken at 10 second intervals from a rooftop camera (facing to the west) on the Atmospheric and Oceanic Sciences (AOS) / Space Science and Engineering Center (SSEC) building — a very bright flash is briefly seen (which also happens to illuminate 2 aircraft contrails aloft).

It’s admittedly very subtle, but a comparison of a highly-enhanced nighttime visible image from the GOES-11 (GOES-West) satellite and a radar reflectivity image from the Davenport, Iowa WSR-88D (below) seems to corroborate the reports from the public of the meteor flash appearing to move “from west to east” (or in this case, from northwest to southeast). The exact time that GOES-11 was scanning the area of the slightly brighter streak was 03:03 UTC (10:03 pm local time), and our best guess of the exact time of the enhanced reflectivity feature on the WSR-88D radar image is 03:04 UTC (10:04 pm local time). GOES-11 and radar images courtesy of Mat Gunshor, CIMSS.

GOES-11 enhanced nighttime visible image + Davenport IA WSR-88D radar reflectivty

Related links:

• SSEC Spotlight
• UW AOS
  
• NWS La Crosse WI
• NWS Davenport IA
• AccuWeather
• National Public Radio
  

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GOES-12 0.65 µm vs GOES-13 0.63 µm visible images

As of 18:34 UTC on 14 April 2010, GOES-13 (launched May 2006, with a Post Launch Test in December 2006) replaced GOES-12 (launched July 2001) as the operational GOES-East satellite  — for more information, see the NOAA NESDIS Satellite Services Division. A sequence of AWIPS images (above) shows the last three GOES-12 visible images followed by the first three GOES-13 visible images centered over the Upper Midwest region of the US during the satellite transition period. Both the GOES-12 and the GOES-13 visible images are enhanced using the “Linear” AWIPS enhancement (see below for more details).

Note that areas of dense vegetation (for example, over river valleys, and also across much of southern Indiana) appear slightly darker on the GOES-13 visible channel images. This is due to the fact that the visible channel on the newer GOES series — GOES-13 and beyond — is a narrower channel (centered at 0.63 µm, vs 0.65 µm for the older GOES satellites) that misses the “brighter” portion of the grass/vegetation spectrum (green plot) that begins to increase rapidly at wavelengths higher than about 0.7 µm (below). You will also notice that the cloud features appear slightly brighter in the last three GOES-13 images — this is due to the fact that the GOES visible detector performance tends to degrade over time, so the visible images from the much  older GOES-12 satellite appear slightly “washed out” in comparison.

GOES-12 vs GOES-13 visible channel spectral response function plots

Note to AWIPS users: because of the different characteristics of the GOES-13 visible channel, it is suggested that you change the default GOES visible image enhancement from “ZA” to “Linear” — as seen in a GOES-13 visible image comparison with those 2 enhancements (below), the GOES-13 imagery can appear too dark with the default “ZA” enhancement.

GOES-13 visible image: “ZA” enhancement vs “Linear” enhancement

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GOES-12 vs GOES-13 Sounder 4.5 µm shortwave IR images

There are also significant improvements in the quality of the GOES-13 Sounder data, due to the fact that GOES-12 had been experiencing filter wheel problems for quite some time. AWIPS comparisons of the last GOES-12 and the first GOES-13 Sounder 4.5 µm shortwave IR images (above) and 6.5 µm water vapor channel images (below) clearly demonstrate the dramatic reduction in noise — in these Sounder composite images, the western portion of the image is GOES-11 (GOES-West) data, while the eastern portion of the image is either GOES-12 or GOES-13 (GOES-East) data. In particular, the 6.5 µm water vapor image is “cleaner” on GOES-13 as a result of “colder” detectors on the newer spacecraft design, which more effectively radiate to space.

GOES-12 vs GOES-13 Sounder 6.5 µm water vapor channel images

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GOES-13 SRSO visible images (centered just south of Amarillo, Texas)

For testing purposes, the GOES-13 satellite was placed into Super Rapid Scan Operations (SRSO) mode on 11 April 2010. In SRSO mode, images are available as frequently as every 1 minute during certain time periods. McIDAS images of GOES-13 0.65 µm visible channel data centered just south of Amarillo, Texas (above; also available as a QuickTime animation) showed the development of deep convection that formed a nice arc-shaped outflow boundary which produced some gusty surface winds (as high as 47 mph at Amarillo TX KAMA, and 32 mph at Clovis NM KCVN) — then some of the thunderstorms later dropped hail up to 1.75 inches in diameter in the northern Texas Panhandle region (after dark, additional storms produced hail up to 2.0 inches in diameter). Note the appearance of a number of overshooting tops, which cast small shadows on the tops of the cloud anvil regions.

Farther to the southeast, GOES-13 visible images centered just southwest of Dallas / Fort Worth, Texas (below; also available as a QuickTime animation) revealed what appeared to be an undular bore that was propagating southwestward through the low-level stratus cloud deck that was covering that area. The passage of this undular bore did not seem to have much of an impact on the surface wind direction, suggesting that the wave was being ducted within a temperature inversion aloft (near the altitude of the cloud deck). The Fort Worth TX 12 UTC rawinsonde data did reveal the presence of some strong low-level inversions.

Such frequent rapid scan imaging will be routinely available with the ABI instrument on the upcoming GOES-R satellite, scheduled to be launched in 2015.

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