A depletion of air in the atmosphere , and consequent reduction in density resulting from a net outflow of air from a particular region, such as that of a trough in the upper westerly jet stream . A divergence in the upper troposphere results from an upward movement of air, which is limited by the existence of the tropopause and stratosphere.
Divergence above is associated with convergence below and an increase in cyclonic vorticity.
This encourages the development of depressions. The Penguin Dictionary of Psychology 2. A Dictionary of Geography 3. convergence A Dictionary of Earth Sciences 4. Oxford University Press 5. All rights reserved.