Cloud Spotting

Analysing the shape, size and altitude of clouds gives meteorologists a good indication of the atmospheric conditions, including air stability, moisture content and motion. Clouds are classified on the basis of the height and form. The three main types for types of cloud are Cumulus, Cirrus and Stratus:

1. Cumulus clouds exhibit flat bases, rising domes with bubble/globular cloud masses. These can grow from unstable air that rises vertically from low altitudes to up to 45,000 feet (in extremely unstable conditions). Cumulus clouds consist water vapour at low altitudes and ice crystals at high altitudes.
2. Cirrus clouds are white, high and have a wispy appearance. They form at high altitudes and are composed of ice crystals, dust or pollution partials.
3. Stratus cloud form at low altitudes as expansive sheets or Stratas. Low-level stratus clouds are composed of water vapour and are usually associated with precipitation.

Rain-producing clouds contain the prefix ‘nimbo’ or suffix ‘nimbus’ within their name.

Classification of clouds:

Cumulus clouds

 

Cirrus and Cirrostratus develop as a result of strong vertical shear

between two air streams. When the upper stream flows faster than

the lower stream wave-like pattern are created.  

 Bands of Altocumulus clouds form as a result of turbulence induced
 by dramatic changes in surface roughness i.e. as air masses flow over
 hills and mountains.

Noctilucent clouds are very rarely seen in the UK. They emerge so
high in the atmosphere that is illuminated by the sun even at night,
estimated to form 70-90km (44-45 miles) above sea level.

Class Exercise:

What type of atmospheric conditions produce these different types of clouds?

Some geeky websites:

http://cloudappreciationsociety.org/

http://www.stuffintheair.com/different-types-of-clouds.html

http://eo.ucar.edu/webweather/cloudmatch.html

A quick and fun match up game available at

http://eo.ucar.edu/webweather/cloudmatch.html