Volcanic ash fall plume over the Kamchatka Peninsula
Suomi NPP VIIRS 0.64 µm visible channel images
AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel images (above) revealed some interesting curved ice floe gyres in the Bering Sea just off the eastern coast of the Russian Kamchatka Peninsula on 07 March 2013. Also evident near the center of the visible images was a long, narrow, and slightly darker feature that was oriented approximately west-to-east, and located to the northwest and north of the village of Ust’-Kamchatsk (station identifier 32408). This darker feature was a volcanic ash fall plume from the Sheveluch Volcano (located 31 miles or 50 km to the northwest), which had experienced eruptions producing volcanic ash (photos) on 02 March and 04 March — the darker color of the narrow strip of volcanic ash made it stand out against the adjacent snow-covered areas (annotated visible image).
A comparison of a Suomi NPP VIIRS 0.64 µm visible channel image with the corresponding false-color Red/Green/Blue (RGB) image (below) also showed the contrast between the narrow strip of ash-covered snow and the surrounding undisturbed snow cover (snow and ice appear as darker shades of red in the RGB image).
Suomi NPP VIIRS 0.64 µm visible channel image + False-color Red/Green/Blue (RGB) image
A comparison of Suomi NPP VIIRS 0.64 µm visible channel, 3.74 µm shortwave IR channel, and 11.45 µm IR channel images (below) showed that the strip of ash-covered snow appeared significantly warmer (darker) on the shortwave IR image, due to the fact that the volcanic ash particles were efficient reflectors of incoming solar radiation. The ash-covered snow even appeared slightly warmer (darker) on the 11.45 µm IR image, since the lower albedo of the ash-covered snow allowed it to absorb more incoming solar radiation.Also evident on the shortwave IR image was a distinct hot thermal anomaly (yellow to red color enhancement) associated with the active Kizimen volcano.
Suomi NPP VIIRS 0.64 µm visible channel, 3.74 µm shortwave IR channel. and 11.45 µm IR channel images
An animation of McIDAS images of MTSAT-2 0.73 µm visible channel data (below; click image to play animation) confirmed that the darker volcanic ash fall plume was a stationary feature, and not an airborne volcanic ash plume. The animation also showed the anticyclonic rotation of the gyres of ice floes just off the east coast of Kamchatka.
MTSAT-2 0.73 µm visible channel images (click image to play animation)