Temperature Inversions An upside-down situation The ‘Normal’ Situation 105’ 38°F 105’ 38°F 64’ 40°F 64’ 40°F 32’ 40°F 32’ 40°F 16’ 41°F 8’ 41°F 16’ 41°F 8’ 41°F Temperature Inversions • These are when the ‘normal’ situations are reversed ie when warmer air overlies colder air. • This can be at low level Temperature Inversions • These are when the ‘normal’ situations are reversed ie when warmer air overlies colder air. • This can be at low level or at high level Temperature Inversions • There is a natural inversion in our atmosphere as the stratosphere is the layer that absorbs most of the ultraviolet radiation (high level) Temperature Inversions • High level inversions are also found in depressions, when the warm sector overlies the cold sector (occlusion) Temperature Inversions • Low level or ground inversions occur in anticyclonic conditions when there is a rapid loss of energy at night. • The air near the surface is cooled by conduction of heat to the cold ground. The lower layer is therefore colder than the air above it. Temperature Inversions • Low level or ground inversions occur in anticyclonic conditions when there is a rapid loss of energy at night. • The air near the surface is cooled by conduction of heat to the cold ground. The lower layer is therefore colder than the air above it. Temperature Inversions • A classic inversion is where the hot emissions given off by industrial chimneys trap in the colder air below Signs of a surface inversion in the early morning Lack of heavy cloud cover Windless or light variable wind Ground Fog Frost (or dew) Smoke from a chimney forming a layer Surface inversion - early morning