Spatially averaged sensible heat fluxes in mountainous terrain for model evaluation (SASHIMI)

Helen Claire Ward1, Manuela Lehner1, Beth Saunders1, Clemens Wastl2 and Daniel Deacu2
1 Department of Atmospheric and Cryospheric Sciences, University of Innsbruck
2 GeoSphere Austria

One of the main challenges in mountain meteorology is the extreme spatial variability of
surface and atmosphere conditions. The substantial differences that occur from place to place
make it very difficult to obtain representative measurements and complicate the evaluation of
numerical weather prediction (NWP) models. In contrast to typical eddy covariance (EC)
measurements, scintillometry can provide area-averaged heat fluxes over larger scales which are
more comparable to the grid box size of NWP models. Studies have shown that scintillometers
can be used in heterogeneous landscapes, in gently sloping terrain and in urban areas. However,
as very few studies have taken place in mountainous terrain, it remains unknown whether
scintillometry can be used successfully in such environments.
The summer Extensive Observation Period (sEOP) of the TEAMx programme offers a perfect
opportunity to address this knowledge gap and find out (i) whether scintillometry can be used in
highly complex terrain, (ii) how scintillometer measurements compare to EC measurements, and
(iii) whether the larger-scale heat fluxes are better suited for comparison with numerical models.
This project will bring together scientists from the Department of Atmospheric and Cryospheric
Sciences, University of Innsbruck and GeoSphere Austria to tackle these research questions.
The proposed work will concentrate on the i-Box site at Kolsass, where multiple EC stations
will be used to capture spatial variability and estimate advection. This project will add a large-
aperture scintillometer to the setup, enabling derivation of sensible heat fluxes over a region
covered by several of the EC stations. The resulting dataset will enable direct comparison of
sensible heat fluxes derived from scintillometry with those from EC. Furthermore, these two
observational datasets will be compared with simulations from the AROME model, contributing
to the ongoing evaluation of AROME and helping to advance numerical modelling in complex
terrain

The proposed scintillometer path at Kolsass measuring 550 m from transmitter (Tx) to receiver
(Rx). Eddy covariance stations are marked by a cross (existing station) and circles (additional
stations). Aerial imagery from Google Earth.