Rodwell–Hoskins mechanism
Climate theory / From Wikipedia, the free encyclopedia
The Rodwell–Hoskins mechanism is a hypothesis describing a climatic teleconnection between the Indian/Asian summer monsoon and the climate of the Mediterranean. It was formulated in 1996 by Brian Hoskins and Mark J. Rodwell [d]. The hypothesis stipulates that ascending air in the monsoon region induces atmospheric circulation features named Rossby waves that expand westward and interact with the mean westerly winds of the midlatitudes, eventually inducing descent of the air. Descending air warms and its humidity decreases, thus resulting in a drier climate during the summer months. The interaction of this atmospheric flow with topography (e.g the Atlas and Zagros mountains) further modifies the effect.
This hypothesis has been advanced to explain the dry climate of the eastern Mediterranean during the summer months, as other explanations involving the Hadley circulation are not plausible during that season. Together with sea and land surface feedbacks, it may also explain the existence of deserts and subtropical anticyclones elsewhere in the world, as well as changes in the Mediterranean climate that coincide with variations of the monsoon.