Meteorology and Atmospheric Physics

, Volume 103, Issue 1–4, pp 45–55 | Cite as

Idealized mesoscale numerical study of Mediterranean heavy precipitating convective systems

  • R. Bresson
  • D. RicardEmail author
  • V. Ducrocq


The western Mediterranean mountainous areas are prone to heavy precipitating events during the fall season. The ingredients that favour these systems are well known but it is still difficult to understand why a precipitating system can become paroxysmal or to forecast the accurate location of the system. To investigate these predictability issues, an idealized framework to simulate quasi-stationary mesoscale convective systems is set up and serves as a basis for studying the sensitivity of the location and intensity of precipitating systems to the characteristics of the low-level upstream flow over the Mediterranean Sea. High resolution simulations are performed with the non-hydrostatic MESO-NH model for an idealized moist unstable flow but using the real topography. Low-level humidity distribution, convective available potential energy and speed of the flow are varied. It is found that various lifting mechanisms are involved to explain the specific location (orographic lifting, cold pool dynamics, low-level convergence due to deflection of the flow by the Alps). When the speed of the upstream flow is increased (decreased) compared to the CTRL run, the area of precipitation moves downstream (upstream). When the mixing ratio of the environment outside of the jet is less (more) than the CRTL run, the system is located more upstream (downstream). When the instability of the upstream flow is increased (decreased) compared to the CTRL run, the convective system moves upstream (downstream). The cold pool strength increases with slower flow and/or more instability. The maximum of rainfall is obtained when the convective system is over the relief with a strong low-level flow or a weak CAPE. The area covered by heavy precipitation is maximum when CAPE is high or low-level flow is strong.


Convective System Heavy Precipitation Event Equivalent Potential Temperature Cold Pool Synthesis View 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Chen, S-H, Lin, Y-L 2005Orographic effects on a conditionally unstable flow over an idealized three-dimensional mesoscale mountainMeteorol Atmos Phys88121CrossRefGoogle Scholar
  2. Chu, C-M, Lin, Y-L 2000Effects of orography on the generation and propagation of mesoscale convective systems in a two-dimensional conditionally unstable flowJ Atmos Sci5738173837CrossRefGoogle Scholar
  3. Davolio, S, Buzzi, A, Malguzzi, P 2006Orographic influence on deep convection: case study and sensitivity experimentsMeteorologische Zeitschrift15215223CrossRefGoogle Scholar
  4. Delrieu, G, Ducrocq, V, Gaume, E, Nicol, J, Payrastre, O, Yates, E, Kirstetter, P-E, Andrieu, H, Ayral, P-A, Bouvier, C, Creutin, J-D, Livet, M, Anquetin, S, Lang, M, Neppel, L, Obled, C, Parent du Châtelet, J, Saulnier, G-M, Walpersdorf, A, Wobrock, W 2005The catastrophic flash-flood event of 89 September 2002 in the Gard region, France: a first case study for the Cévennes-Vivarais Mediterranean Hydrometeorological ObservatoryJ Hydrometeor63452CrossRefGoogle Scholar
  5. Ducrocq, V, Nuissier, O, Ricard, D, Lebeaupin, C, Thouvenin, T 2008A numerical study of three catastrophic precipitating events over western Mediterranean region (southern France). Part II: Mesoscale triggering and stationarity factorsQuart J Roy Meteor Soc34131145CrossRefGoogle Scholar
  6. Gheusi, F, Stein, J 2003Small-scale rainfall mechanisms for an idealized convective southerly flow over the AlpsQuart J Roy Meteor Soc12918191840CrossRefGoogle Scholar
  7. Lafore, J-P, Stein, J, Asencio, N, Bougeault, P, Ducrocq, V, Duron, J, Fischer, C, Héreil, P, Mascart, P, Masson, V, Pinty, J-P, Redelsperger, J-L, Richard, E, Vilà-Guerau de Arellano, J 1998The Meso-NH atmospheric simulation system. Part I: Adiabatic formulation and control simulations. Scientific objectives and experimental designAnn Geophys1690109CrossRefGoogle Scholar
  8. Lin, Y-L, Chiao, S, Wang, T-A, Kaplan, ML, Weglarz, RP 2001Some common ingredients for heavy orographic rainfallWea Forecast16633660CrossRefGoogle Scholar
  9. Miglietta, MM, Buzzi, A 2001A numerical study of moist stratified flows over isolated topographyTellus A53481499CrossRefGoogle Scholar
  10. Nuissier, O, Ducrocq, V, Ricard, D, Lebeaupin, C, Anquetin, S 2008A numerical study of three catastrophic precipitating events over western Mediterranean region (Southern France). Part I: Numerical framework and synoptic ingredientsQuart J Roy Meteor Soc134111130CrossRefGoogle Scholar
  11. Ricard, D 2005Modélisation à haute résolution des pluies intenses dans les Cévennes: Le système convectif des 13 et 14 octobre 1995La Météorologie 8e série482838Google Scholar
  12. Rotunno, R, Ferretti, R 2001Mechanisms of intense Alpine rainfallJ Atmos Sci5817321749CrossRefGoogle Scholar
  13. Rotunno, R, Klemp, JB, Weisman, ML 1988A theory for strong, long-lived squall linesJ Atmos Sci45463485CrossRefGoogle Scholar
  14. Schumacher, RS, Johnson, RH 2005Organization and environmental properties of extreme-rain-producing mesoscale convective systemsMon Wea Rev133961976CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.GAME/CNRM, Météo-France/CNRSToulouseFrance

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