Vertical fluxes in katabatic flows

✍ Scribed by P. C. Manins

• Publisher: Springer
• Year: 1992
• Tongue: English
• Weight: 612 KB
• Volume: 60
• Category: Article
• ISSN: 0006-8314
• DOI: 10.1007/bf00122066

✦ Synopsis

Katabatic flow is a dynamical process occurring on relatively calm, clear nights above sloping terrain. Its existence is dependent on long-wave radiative transfer, particularly radiative flux divergence within the air itself, for both its generation and (it is concluded here), along with advective warming, for much of its retardation.

Utilising sounding data closely spaced in time, a discussion is presented of the importance of surface shear, interfacial shear, advective warming and radiative divergence in a strong katabatic flow. It is concluded that radiative divergence is important in generating static and dynamic instabilities in the flow. The role of radiative cooling in mixing of momentum has largely been ignored so far, and might explain why higher-order models tend to overestimate katabatic speeds on smooth slopes.