October 4, 2010 - Clouds off Baja California

Clouds off Baja California

Cloud-watching is an enjoyable pastime, especially lying back on grass or a boat and imagining animals and familiar objects as they appear in the unique shapes formed by the clouds overhead. Satellites observe clouds from a different perspective from far above the cloud tops and over thousands of kilometers at a time - but the images they produce are as stirring to the imagination as any land-based cloud watching. Not only do shapes appear for interpretation by creative minds, but large-scale patterns that are not visible in any other way become clearly revealed, encouraging scientific study. As data accumulates, so does our knowledge of clouds and cloud forms. It is becoming abundantly clear that clouds affect climate and this has become an important and active area of research.

A very complex array of clouds were captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) perched on the Aqua satellite as it passed over the Pacific Ocean west of Baja California on September 29, 2010. The primary formation is marine layer clouds. A marine layer is an air mass that forms over a large body of water in the presence of temperature inversion. Stratus and stratocumulus clouds will form at the top of a marine layer, making a mottled pattern as seen in much of this image. The designs in the stratocumulus layer indicate some instability in the layer - possibly turbulence in the air or a change in the water temperature underlying that area of cloud.

In the upper right half of the image, west of Santa Barbara, California, white streaks can be seen in the clouds. These are ship tracks, which are bright streaks that are formed around the exhaust released by ships into the still ocean air. Water molecules collect around aerosols from exhaust, forming a cloud seed. As more water accumulates, a cloud is formed. Ship tracks are brighter (more reflective) and carry more water than the surrounding cloud layer, and may inhibit rainfall. Scientists study ship tracks to learn about how human-produced aerosols affect cloud formation and properties, including potential effects of aerosol on climate.

Image Facts
Satellite: Aqua
Date Acquired: 9/29/2010
Resolutions: 1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC