Atmospheric boundary layers over mountainous terrain and urban areas are far more complex
than over flat and horizontally homogeneous terrain. Orographic wind systems can result in possible
sublayers, while increased heating and turbulence lead to deeper boundary layers over and
downwind of cities. Both types of environment are associated with extreme spatial variability, hence
observing the boundary layer in these landscapes is challenging. However, remote sensing using
ground-based ceilometers offers a promising means of obtaining high resolution timeseries
information about boundary layer structure and evolution.
This project will use data from a network of ceilometers that is operated by GeoSphere Austria
(GSA) and Austro Control (ACG) to study spatial patterns in boundary layer structure in the Inn Valley,
Austria. Data are available from seven ceilometers (located at Telfs, Kematen, Innsbruck Airport,
Innsbruck City and Jenbach, Radfeld and Kufstein), providing coverage in and around the city of
Innsbruck and along the valley towards the valley exit region. Meteorologists from GSA and University
of Innsbruck will co-supervise a student, thus making a joint effort to understand the spatial and
temporal patterns of mixed layer heights as found in the ceilometer reflectivity dataset. First, the
automatic detection of boundary layer heights from ceilometers will be compared with other
methods (e.g. radiosonde, microwave radiometer). Next, the variation in boundary layer height along
the Inn Valley will be investigated through case studies in different seasons and for different weather
patterns. Finally, differences in boundary layer height over Innsbruck compared to the surroundings
will be quantified. This project brings together expertise at GSA and UIBK on boundary layer
development, mountain meteorology and urban atmospheres. Findings will support TEAMx efforts to
improve understanding of the mountain boundary layer and will be of interest to both the mountain
meteorology and urban climate communities.

 

Helen Claire Ward (Plankl)

 

Johannes Vergeiner

Alexander Hieden

Kathrin Baumann-Stanzer

GeoSphere Austria