A comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and 6.7 µm water vapor channel data (above) revealed the presence of widespread mountain waves across parts of the Mid-Atlantic states on 20 February 2013. Parallel bands of rotor clouds helped to identify the location of these waves (caused by strong northwesterly winds interacting with the terrain of the Appalachian Mountains) where ample moisture was present, but in many areas the atmosphere at that altitude was too dry to support rotor cloud development — this demonstrated the advantage that water vapor imagery has in helping to know the total areal coverage of such mountain wave activity.

Mountain waves can be an aviation hazard, since they are capable of generating turbulence. Plots o pilot reports of turbulence within +/- 30 minutes of the MODIS overpass time indicated that there was one report of severe turbulence in the 7000-9000 foot altitude range over extreme northwestern Virginia, along with moderate turbulence likely associated with rotor circulation wind shear in northern Virginia and southern Virginia. In addition, there was a report of moderate clear air turbulence at 36,000 feet over eastern Chesapeake Bay, suggesting that these mountain waves might be vertically propagating.

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McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) showed the development of a mesoscale eddy immediately downwind of San Clemente Island off the coast of southern California on 17 February 2013. The eddy was helping to push the marine boundary layer farther inland, bringing stratus clouds and cooler temperatures to some coastal locations.

A comparison of AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data (below) revealed that cloud top IR brightness temperatures of the marine layer stratus were in the 6-7º C range (darker blue color enhancement).

A 250-meter resolution Aqua MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Direct Broadcast site (below) showed the fine structure of the center of the eddy circulation.

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McIDAS images of MTSAT-2 0.73 µm visible channel data (above; click image to play animation) showed a small polar low that was developing just south of the sea ice edge in the western Bering Sea on 15 February 2013. Widespread cloud streets could be seen streaming southwestward off the sea ice edge as colder air was being drawn into the circulation of the low as it propagated westward.

Greater detail in the sea ice, the cloud streets, and the curved cloud bands associated with the circulation of the polar low could be seen in an AWIPS comparison of 1-km resolution Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images (below). In the RGB image, snow and ice appear as darker shades of red, in contrast to supercooled water droplet clouds (which appear as varying shades of white) — and clouds that are becoming glaciated also exhibit a pink to lighter red appearance.

Several hours later, a comparison of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) and 3.74 µm shortwave IR images at 15:00 UTC on 16 February (below) showed the tight circulation of the polar low approaching the east coast of Russia’s Kamchatka Peninsula. Even though a thin veil of high clouds covered most of the Kamchatka Peninsula (VIIRS 11.45 µm IR image), another feature of interest was the large (but diffuse) bright spot seen on the DNB image, which coincided with a small shortwave IR thermal anomaly or “hot spot” (darker black to yellow enhancement) which exhibited a maximum IR brightness temperature of 43º C. This feature was the Plosky Tolbachik Volcano, which was experiencing strong seismic activity and producing effusive lava flows at the time (KVERT site).

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A Meteor entered the Earth’s atmosphere over the Ural Mountains of western Russia today at approximately 0320 UTC (09:20 AM local time). The visible image from just after sunrise, above, from the Chinese FY-2D satellite shows an east-west plume, likely from the meteor, near Chelyabinsk. Meteosat-9 also captured the event (YouTube | EUMETSAT), as did Meteosat-10.

FY-2D has multiple channels. An animation of the visible (0.73 µm), near-infrared (3.8 µm), ‘water vapor’ (6.8 µm) and far-infrared (11.0 µm) is shown above. The signature of the meteor vapor trail is present in each of the channels. A before/after comparison (03:00 and 03:30 UTC) of FY-2D 0.73 µm visible, 3.8 µm shortwave IR, 6.8 µm water vapor, and 10.8 µm IR window channel images is shown below.

An oblique view using Visible (0.73 µm) images from the Japanese MTSAT-2 satellite (below) revealed that the stratospheric component of the meteor vapor trail could be seen for as long as 9 hours with the aid of illumination from the sun.

A comparison of MTSAT-2 Shortwave Infrared (3.75 µm), Infrared Window (10.8 µm) and Visible (0.73 µm) images (below) showed that the meteor vapor trail exhibited a warm (darker gray) signature on the Shortwave Infrared images, due to this channel’s sensitivity to reflected solar radiation — that signature was seen to disappear with the loss of daytime sunlight. Since the vapor trail was not a particularly dense cloud, it did not exhibit a distinct signature on the Infrared Window images; however, there was still a faint thermal signal due to the fact that the mean meteor trail infrared brightness temperature of around 242 K (-31 ºC) was significantly warmer than that of the background infrared brightness temperature of space (165 K or -108 ºC).

(Added, October 2013: This event has been written up in a journal article: Link)

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