## 5 Towards Enhanced Use of High Resolution EO Data in Earth System Modelling
### Satellite-Focused Field Campaign: The Concordiasi Example  
Concordiasi was a field campaign, part of the Thorpex experiment [328] dedicated to the study of the atmosphere above Antarctica as well as the land surface of the Antarctic continent and the surrounding sea-ice. In 2010, an innovative constellation of balloons, including 13 driftsondes, provided a unique set of measurements covering both a large volume and time. The balloons drifted for several months on isopycnic surfaces in the lowermost stratosphere around 18 km, circling over Antarctica in the winter vortex, performing, on command, hundreds of soundings of the troposphere. Many dropsondes were released to coincide with overpasses of the Meteorological Operation (MetOp) satellite, allowing comparison with data from the Infrared Atmospheric Sounding Interferometer (IASI). IASI is an advanced infrared sounder that has a large impact on NWP systems in general. However, there are some difficulties in its use over polar areas because the extremely cold polar environment makes it more difficult to extract temperature information from infrared spectra and makes it difficult to detect cloud properties.  
A number of results have been described in the Concordiasi workshop report [329; 330]. Although the performance of NWP analyses and forecasts have dramatically improved over the last decade, large systematic differences remain in analyses from various models for temperature over Antarctica and for winds on the surrounding oceans. A comparison between short-range forecasts and the Concordiasi data was investigated for various NWP centres. Results show that models suffer from deficiencies in representing near-surface temperature over the Antarctic high terrain. The very strong thermal inversion observed in the data is a challenge in numerical modeling because models need both a very good representation of turbulent exchanges in the atmosphere and of snow processes to be able to simulate this extreme atmospheric behavior. It has been shown that satellite retrievals also have problems representing the sharp inversions over the area.  
An example of comparison of such profiles is provided in the Figure 28 (courtesy of T August, EUMETSAT). At the surface, particular attention has been paid to observing and modeling the interaction between snow and the atmosphere. This research has led to an improvement of snow representation over Antarctica in the Integrated Forecasting System (IFS) model at ECMWF [331]. Coupled snow-atmosphere simulations performed at Meteo-France with the Crocus and Applications of Research to Operations at Mesoscale (AROME) models have been shown to realistically reproduce the internal and surface temperatures of the snow as well as boundary layer characteristics [332]. In this example of the Concordiasi campaign, datasets obtained from the field experiment over snow and sea ice have proven invaluable to document the quality and deficiencies of both satellite retrievals and NWP model fields. This has helped to provide directions in which to explore the improvement of models, which will be beneficial for weather prediction and climate monitoring. The validation and diagnostics of numerical weather modelling over snow and sea-ice with Earth observations pose challenges because of the lack of regular in situ data and because satellite observations can be difficult to interpret in those areas. Field experiments can help to provide precious information to assist scientists in this validation work.