fuckyeahfluiddynamics:

The volcanoes of the South Sandwich Islands, located in the South Atlantic, have a notable effect on cloud formation in this satellite photo. Visokoi Island, on the right, sheds a wake of large vortices that distort the cloud layer above it.  On the left, Zavodovski Island’s volcano does the same, with the added effect of low-level volcanic emissions, which include aerosols. These tiny particles provide a nucleus around which water droplets form, causing an marked increase in cloud formation visible in the bright tail streaming off the island. (Photo credit: NASA, via Earth Observatory)

fuckyeahfluiddynamics:

Two interesting sets of clouds are featured in this satellite photo of the Canary Islands and the coast of Africa. In the upper part of the picture, closed cell stratocumulus clouds cover the ocean. As the wind drives these clouds over the islands, their pattern is disturbed by mountains that force the lower layers of air up and around, forming von Karman vortices and wakes that mingle and twist the cloud patterns to the south of the islands. (Photo credit: European Space Agency; via Wired)

fuckyeahfluiddynamics:

Cloud streets flowing south across Bristol Bay hit the Shishaldin and Pavlof volcanoes, which part the air flow into distinctive swirls called von Karman vortex streets. As air flows around the volcano, a vortex is shed first on one side, then the other. Although the usual example for this type of flow is the wake of a cylinder, vortex streets can extend behind any non-aerodynamic body immersed in a flow. The same phenomenon is responsible for the singing of power lines in the wind.  As astronaut Dan Burbank observes, “It’s classic aerodynamics, but on a thousands of miles scale.” (Photo credit: Dan Burbank, NASA)