Project Summary:

Hofsjökull (1782 m) is an isolated, glacier covered mountain in Central Iceland with nearly circular shape and extremely smooth surface. At an diameter of around 30 km it rises about 1000 m above its surrounding. There are presumably only few mountains on earth of this scale whose shape comes so close to that assumed in idealized theoretical work. This makes Hofsjökull an ideal field laboratory for validation purposes. It is a central aim of FLOHOF to explore the response of mountain induced gravity waves to changes of the inflow in time. As yet, this topic received little attention from the theoreticians. We are not aware of any campaign to address this topic observationally.
During summer 2007 the FLOHOF field campaign has been conducted in the Hofsjökull area. Permanent meteorological stations have been placed around and over the mountain. In addition atmospheric profiles of temperature, humidity and wind have been taken by small umnanned remotely piloted airplanes, tethered balloons, and pilot balloon ascents. The campaign has been accompanied by extensive numerical simulations using MM5 and WRF.
There are also attempts to make progress with linear theories on the description of non-stationary gravity waves. In particular, the observations collected during FLOHOF will be used as input to linear models. Evaluation of the observations is of primary importance at the moment. It is planned to perform first a principal oscillation analysis (POP) in order to find out about main frequencies and the related pressure patterns. Corresponding enquiries into the capability of POPs to handle spatially inhomogeneous data sets are under way.

J. Reuder, H. Olafsson, S. Mayer, M. Jonassen       last modified: 13.09.2007