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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AWIPS II images of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel images (above; click image to play animation) captured an example of a “Bennett Island cloud plume” off the north coast of Siberia on 13-14 February 2013. Minimum IR brightness temperature values reached -51 C during the early stages of plume development. Due to the orientation of the AWIPS II Northern Hemisphere map projection, the images were rotated 90 degrees to the left, so that North was approximately toward the top of the images. Full-resolution (375-meter) VIIRS data are now being distributed to Alaska Region AWIPS II users.

A VIIRS IR image with an overlay of GFS190 model 500 hPa winds (above) showed a generally light southeasterly flow of 10-20 knots across the region. This was in good agreement with rawinsonde data (below) from the Chokurdah, Russia site (located south of Bennett Island, over northern Siberia).

 

 

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A comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel, 11.0 µm IR channel, and 6.7 µm water channel data (above) revealed subtle Kelvin-Helmholtz (K-H) billow features across parts of eastern Iowa on 10 February 2013 that were only apparent in the water vapor imagery. In the vicinity of these elongated mesoscale wave signatures, there were a few pilot reports of light to moderate turbulence (primarily within the 14,000-21,000 foot altitude range).

An animation of 4-km resolution GOES-13 6.5 µm water vapor images (below) did not show any evidence of these K-H billow features within the dry slot that was wrapping around the center of a large and intense winter storm that was producing blizzard conditions from Nebraska to North Dakota.

A comparison of the 1-km resolution MODIS water vapor image with the corresponding 4-km resolution GOES-13 water vapor image (below) demonstrated the advantage of improved spatial resolution for the detection of such potentially-important mesoscale features. The slight northwestward shift of features seen on the GOES-13 water vapor image is due to parallax.

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