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Laboratoire d'aérologie |  |
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Laboratoire d'aérologie | |
| HAL: hal-00659497, version 1 |
| DOI: 10.1002/qj.1864 |
| Detailed view |  Export this paper |
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| Quarterly Journal of the Royal Meteorological Society 138, 667 (2012) 1652-1667 |
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| Assimilation of water-vapour airborne lidar observations: impact study on the COPS precipitation forecasts |
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| S. Bielli 1M. Grzeschik 1 |
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| (2012) |
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| 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 |
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| 1: | Laboratoire d'aérologie (LA) |
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CNRS : UMR5560 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III |
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| 2: | Institut Pierre-Simon-Laplace (IPSL) |
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CNRS : FR636 – Institut de recherche pour le développement [IRD] – CEA – CNES – INSU – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Versailles Saint-Quentin-en-Yvelines – Ecole normale supérieure de Paris - ENS Paris |
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| 3: | Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) |
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CNRS : UMR8190 – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Versailles Saint-Quentin-en-Yvelines – INSU |
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| 4: | Université Pierre et Marie Curie - Paris 6 (UPMC) |
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Université Pierre et Marie Curie [UPMC] - Paris VI |
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| 5: | Géosciences Montpellier (GM) |
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CNRS : UMR5243 – Université Montpellier II - Sciences et techniques |
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| 6: | Deutsches Zentrum für Luft- und Raumfahrt (DLR) |
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Deutsches Zentrum für Luft- und Raumfahrt (DLR) |
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| 7: | Department of Meteorology and Geophysics, University of Vienna |
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University of Vienna |
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| 8: | Groupe d'étude de l'atmosphère météorologique (CNRM-GAME) |
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CNRS : URA1357 – INSU – Météo France |
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| space |
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| Subject | : | Sciences of the Universe/Earth Sciences/Meteorology |
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| LEANDRE 2 – WALES – AROME – VERA |
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| hal-00659497, version 1 | |
| http://hal.archives-ouvertes.fr/hal-00659497 | |
| oai:hal.archives-ouvertes.fr:hal-00659497 | |
| From: Catherine Cardon | |
| Submitted on: Thursday, 12 January 2012 21:41:13 | |
| Updated on: Thursday, 6 December 2012 11:01:39 | |
