Actinae in the North Pacific Ocean

March 29th, 2008 |

AVHRR false color images (Animated GIF)

AVHRR false color imagery (above; viewed using Google Earth) and GOES-11 visible channel imagery (below) revealed a family of cyclonic vorticies¬† propagating westward across the eastern North Pacific Ocean on 29 March 2008. The radially-banded cloud features that form such cloud swirls are known as actinae or actinoform clouds, and they are seen occasionally in the marine stratocumulus cloud field over the Pacific Ocean — for example, other similar cases were observed in March 2007 and June 1997. This type of cloud pattern was first observed on TIROS V imagery way back in August 1962 and October 1962.

GOES-11 visible images (Animated GIF)

2 Responses to “Actinae in the North Pacific Ocean”

  1. Joel Gratz says:

    The Actinae look amazing, but can you comment on what appears to be NE-to-SW oriented waves the propogate ESE through the entire cloud field? This is most evident on the visible animation…thanks!

  2. scott.bachmeier says:

    Good observation, Joel — gravity waves such as those you point out are observed quite frequently in the marine stratucumulus cloud field over the eastern Pacific. The strong marine layer temperature inversion acts as a “duct” to allow these waves to propagate for long distances, relatively unperturbed.

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