Atmospheric fronts are perhaps the most common phenomena appearing on weather maps and are commonly defined by a large temperature contrast across a narrow zone near the earth's surface. However, fronts are more than a simple division of air masses with different thermodynamic properties.
Fronts are a crossroad for interaction between the lower and upper levels of the atmosphere. They also play an important role in the energetics of weather systems, serves as a major link for the interaction between cloud-scale phenomena and the larger planetary circulation, and act as efficient vehicles for the transport of chemical tracers into the upper atmosphere and over long distances.