In the Winter 2014 newsletter, I talked about trade winds and briefly touched on trade wind inversions. Inversions have a big impact on the weather we see in Hawaii, and knowing more about them may be of interest to pilots.
What Is An Inversion?
Temperature normally decreases with height in the atmosphere. (The higher you go, the colder it gets.) For dry air, the temperature drops about 5.4°F for every 1000 feet, or about 9.8°C for every kilometer. An inversion is a layer where the temperature either remains the same or increases with height. It is the result of an outside force, such as a change in airmass along a front where warm air overruns cold air. The typical driving force we see in Hawaii associated with the trade winds is due to sinking air associated with high pressure systems.