Remote Sensing and GIS

  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)