Von Karman vortices south of the Aleutian Islands

April 14th, 2011 |

 

POES AVHRR 0.86 µm visible channel images

POES AVHRR 0.86 µm visible channel images

AWIPS images of POES AVHRR 0.86 µm visible channel data (above) revealed a pair of von Karman vortices streaming southward from the Aleutian Islands of Alaska on 14 April 2011. In this 2-image comparison, note that the cloud features were moving, but the ice in the Bering Sea remained stationary.

An overlay of MADIS low-level atmospheric motion vectors (or “cloud-tracked winds”) indicated that northerly winds across the region were generally in the 20-30 knot range (below).

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR Cloud Top Temperature product

POES AVHRR Cloud Top Temperature product

The corresponding POES AVHRR Cloud Top Temperature (CTT) product images (above) indicated that CTT values for these von Karman vortex features were generally in the -10 to -15º C range, while POES AVHRR Cloud Top Height (CTH) product images (below) showed that the tops of the clouds were  around 1-2 km.

POES AVHRR Cloud Top Height products

POES AVHRR Cloud Top Height products

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