Assimilation of water-vapour airborne lidar observations
- Author(s)
- S. Bielli, M. Grzeschik, E. Richard, C. Flamant, C. Champollion, C. Kiemle, M. Dorninger, P. Brousseau
- Abstract
The Convective and Orographically-driven Precipitation Study (COPS) carried out in summer 2007 over northeastern France and southwestern Germany provided a fairly comprehensive description of the low-troposphere water-vapour field, thanks in particular to the deployment of two airborne differential absorption lidar systems. These lidar observations were assimilated using the 3D-Var assimilation system of the Application of Research to Operations at MEsoscale (AROME) numerical weather prediction mesoscale model. The assimilation was carried out for the period 4 July-3 August by running a three-hour forward intermittent assimilation cycle. First, the impact of the lidar observations was assessed by comparing the analyses with a set of more than 200 independent soundings. The lidar observations were found to have a positive impact on the analyses by reducing the dry bias in the first 500 m above ground level and by diminishing the root-mean-square error by roughly 15% in the first km. Then the impact of the lidar observations was assessed by comparing the precipitation forecasts (obtained with and without the lidar observations for the period 15 July-2 August) with the gridded precipitation observations provided by the Vienna Enhanced Resolution Analysis. In general, the impact was found to be positive but not significant for the 24 h precipitation and positive and significant for the 6 h precipitation, with an improvement lasting up to 24 h. Some selected case studies show that the improvement was obtained through a better depiction of convection initiation or through a more accurate positioning of the precipitation systems.
- Organisation(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- Université Toulouse III Paul Sabatier, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université Paul-Valéry Montpellier 3, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Centre national de recherches météorologiques (CNRM)
- Journal
- Quarterly Journal of the Royal Meteorological Society
- Volume
- 138
- Pages
- 1652-1667
- No. of pages
- 16
- ISSN
- 0035-9009
- DOI
- https://doi.org/10.1002/qj.1864
- Publication date
- 12-2011
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105206 Meteorology
- Keywords
- ASJC Scopus subject areas
- Atmospheric Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/47354f8c-45f5-4259-8796-e3fb0303abe5