Following Coastlines

(NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey.)

On April 8, 2014, Landsat 8 captured this classic example of marine stratocumulus clouds off the coast of China. The ocean is cool and, unlike the land, does not heat up much throughout a day. Cool, moist marine air commonly gives rise to dense clouds over the ocean. (Note that the image is false-color, giving the blues an unnatural tone.)

In this case, an onshore wind carries the clouds from the ocean toward the land. But the land is warmer, drier, and unfavorable for cloud growth. As a result, any marine clouds that move onshore tend to evaporate, leaving a cloud layer that traces the coastline. (Source: Earth Observatory)

Solitary Circulation

(NASA Earth Observatory image by Joshua Stevens, using MODIS data from LANCE/EOSDIS Rapid Response)

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image of a strange system off the coast of Morocco on July 10, 2016. “It looks like a hurricane, but it's not," Van Diedenhoven said. Instead, the system is very small—about 100 kilometers across—and is made up of shallow clouds. “Hurricanes have a greater vertical extent. This is really just a cute, dynamic feature in the atmosphere." (Source: Earth Observatory)

Making Waves

(NASA image by Jeff Schmaltz, using MODIS data from LANCE/EOSDIS Rapid Response.)

On November 27, 2015, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image of icebergs floating offshore of South Georgia Island, more than 1,600 kilometers (1,000 miles) east-northeast of Tierra del Fuego. Two of the larger bergs are big enough to force air masses up and over the ice. The resulting ripples in the atmosphere give rise to “wave clouds." The smaller bergs only produce a “cloud wake." Just as a ship leaves a V-shaped wake in the water, icebergs can leave behind similar wake in low-level clouds. (Source: Earth Observatory)

 

  Riding the Wave

(NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey)

On August 13, 2016, the Operational Land Imager (OLI) on Landsat 8 captured this image of clouds off the coast of Mauritania. You can't see it directly, but air masses from Africa and the Atlantic Ocean are colliding in this image. There is, however, a visibly striking outcome: The collision produces a wave structure in the atmosphere. Parts of these waves are favorable for cloud formation, while other parts are not.

The dust blowing out from Africa appears to be “riding the waves." Dust has been known to affect cloud growth, but it probably has little to do with the cloud pattern observed here.