116th Colloquium

Title：Downslope windstorms and foehn flows around the world: a historical overview and open research questions

Speaker：Dr. Annette Miltenberger (Institute for Climate and Atmospheric Science, University of Leeds, Leeds, UK)

Date： 2017/9/26(Tue), Time: 13:30-15:30

Venue： Center for Computational Sciences, Meeting Room A

Abstract：

Foehn flows and downslope windstorms are prominent mesoscale weather phenomena in many mountain ranges across the globe. The climatology and characteristics of foehn flows in different geographic locations, ranging from the Alps to the Antarctic mountain ranges, are discussed and compared. Naturally, people living in mountainous regions have had a long standing interest in the formation and prediction of downslope windstorms and foehn flow. Accordingly, a number of mechanisms have been proposed to explain the warm nature of foehn flow and its descent into the lee side valleys. A brief historical overview on the evolution of these theories will be followed by a summary of our current understanding of the mechanisms for foehn air warming and downstream descent. Based on the discussion of the foehn flow climatologies, the relative importance of these mechanisms are investigated for different mountain ranges and various upstream conditions. The importance of regional difference will be highlighted with the example of foehn flows in the eastern and western sections of the Alpine range, which are often associated with weak and strong upstream ascent of the foehn air masses, respectively. Key open research questions regarding these aspects of foehn flow are highlighted in the discussion.