Weather Cloud Formation May 19, 2008

Adiabatic Temperature Changes When air is allowed to expand, it cools, and when its is compressed, it warms. Do you know of any examples?

Water’s Changes of State

Adiabatic Rate Dry adiabatic rate – only applies to air that is unsaturated –10°C for every 1000 meters Wet adiabatic rate – only applies to air that is saturated –5-9°C for every 1000 meters Why do you think there is a difference between the wet and dry adiabatic rate? The latent heat absorbed or released by the water.

Processes That Lift Air Orographic Lifting Frontal Wedging Convergence Localized Convective Lifting

Orographic Lifting Orographic lifting is the lifting that occurs when elevated terrains, such as mountains, act as barriers to air flow.

Frontal Wedging Frontal wedging is what happens when a mass of warm air and a mass of cool air come together. The less dense warm air rises above the more dense cool air.

Convergence Convergence is what happens when there is a collision between contrasting air masses.

Localized Convective Lifting Localized convective lifting is caused by unequal heating of the Earth’s surface. This causes pockets of air to be warmed more than the surrounding air.

Summary What is adiabatic temperature change? Why is there a difference between the dry adiabatic rate and the wet adiabatic rate? Describe orographic lifting. Describe frontal lifting. Describe convergence. Describe localized convective lifting.