Clouds and Moisture

Antarctica has a climate with average temperatures well below zero degrees Fahrenheit. The annual average high temperature in Antarctica is -49 degrees Fahrenheit. Although Antarctica's atmosphere is normally below freezing, there can still be water droplets, along with ice crystals, found in the clouds. In the interior of Antarctica the temperature is much colder, causing the clouds to be made up of solely ice crystal particles. The consistency of the clouds made solely of ice crystals, are mostly thinner and fine in form. Due to the climate of Antarctica, deep convective clouds, like those found in thunderstorms, cannot be found in Antarctica’s atmosphere. Deep convective clouds are classified as cumulonimbus clouds that can be many kilometers thick, with its base near the Earth’s surface. For these cumulonimbus clouds to form there must be a warm surface to start the convection of the cloud, a characteristic not found in Antarctica.
Some common clouds found in Antarctica are lenticular clouds.

Standing Lenticular clouds over the Transarctic Mountains, common among mountain ranges.
Image courtesy of http://icestories.exploratorium.edu/dispatches/altocumulus-standing-lenticular-clouds

Lenticular clouds are often formed when mountains create an obstruction for the wind flow, creating turbulence and uplift. Lenticular clouds are often lens shape stationary clouds formed in high altitude, perpendicular in alignment to the wind direction. How can clouds be created due to the obstruction of wind flow? An offer to this explanation is when moist air flows over a mountain range, standing waves of air can form on the down side of the mountain. Then the temperature in the standing air wave must reach the dew point in order for moisture in the air to condense and form lenticular clouds. Dew point is the temperature air must be cooled, at constant air pressure, in order for saturation to occur in respect to a plane surface of water. In order to create saturation the rate of evaporation and condensation must be equal. However, just because the air temperature has reached the dew point temperature does not mean there is going to be precipitation. The process for rain or snow is more complicated than the dew point, taking into consideration the type and size of cloud condensed nuclei that water vapor can condense upon is another process.

References:
·      http://traveltips.usatoday.com/average-temperature-antarctica-13726.html

·      http://earthobservatory.nasa.gov/Features/Clouds/clouds5.php

·      http://en.wikipedia.org/wiki/Lenticular_cloud

·      http://en.wikipedia.org/wiki/Dew_point

·      http://www.antarctica.ac.uk/about_antarctica/geography/weather/clouds.php

·      http://weathersavvy.com/Q-Science_Dewpoint.html