Home About HyMeX
Motivations
Science questions
Observation strategy
Modelling strategy
Target areas
Key documents
Organisation
International coordination
Working groups
Task teams
National contributions
Endorsements
Resources
Database
Data policy
Publications
Education and summer schools
Drifting balloons (BAMED)
SOP web page
Google maps data visualisation
Workshops Projects
ASICS-MED
MOBICLIMEX
MUSIC
IODA-MED
REMEMBER
FLOODSCALE
EXAEDRE
Offers Links Contacts
Science & Task teams
Science teams
Task teams
Implementation plan
Coordination
International Scientific Steering Committee (ISSC)
Executive Committee for Implementation and Science Coordination (EC-ISC)
Executive Committee - France (EC-Fr)
HyMeX France
HyMeX Italy
HyMeX Spain
Archive
by Ricard, D., Ducrocq, V. and Auger, L.
Abstract:
A climatological approach is developed to characterize the mesoscale environment in which heavily precipitating events (HPEs) grow over a mountainous Mediterranean area. This climatology that is based on three-dimensional variational data assimilation (3D-Var) mesoscale analyses is performed for a 5-yr period, considering cases with daily precipitation of >150 mm occurring over southern France during autumn. Different diagnostics are used to document the time evolution of mesoscale features associated with the HPEs for initiation, mature, and dissipation stages. To underline differences according to the location of precipitation, four subdomains are also considered: Languedoc-Roussillon, Cévennes-Vivarais, South Alps, and Corsica. Composite analyses show that these events are driven by some common features (slowly evolving trough–ridge pattern and diffluent midlevel flow). Instability and moisture are transported by the low-level jet (LLJ) toward the target area from their sources, which are located upstream over the Mediterranean Sea. Strong moisture convergence is located within the left exit of the LLJ. These parameters reach a maximum during the mature stage. During the life cycle of the HPEs, the low-level winds rotate clockwise. Composite analyses also show that the synoptic and mesoscale patterns can differ greatly as a function of the location of the precipitation. Indeed, the LLJ varies from southeasterly to southwesterly. The midlevel flow varies from southerly to southwesterly. The areas of high moisture and instability are stretched in different orientations. Long-lasting events are associated with a more pronounced quasi-stationary trough–ridge pattern, higher values of CAPE, a wetter troposphere, and faster LLJ. The most-heavily precipitating events are found to be in general associated with higher values of these parameters or with a low-level inflow that is closer to perpendicular to the relief.
Reference:
Ricard, D., Ducrocq, V. and Auger, L., 2012: A Climatology of the Mesoscale Environment Associated with Heavily Precipitating Events over a Northwestern Mediterranean AreaJ. Appl. Meteor. Climatol., 51, 468-488.
Bibtex Entry:
@Article{Ricard2011,
  Title                    = {A Climatology of the Mesoscale Environment Associated with Heavily Precipitating Events over a Northwestern Mediterranean Area},
  Author                   = {Ricard, D. and Ducrocq, V. and Auger, L.},
  Journal                  = {J. Appl. Meteor. Climatol.},
  Year                     = {2012},

  Month                    = {March},
  Number                   = {3},
  Pages                    = {468-488},
  Volume                   = {51},

  Abstract                 = {A climatological approach is developed to characterize the mesoscale environment in which heavily precipitating events (HPEs) grow over a mountainous Mediterranean area. This climatology that is based on three-dimensional variational data assimilation (3D-Var) mesoscale analyses is performed for a 5-yr period, considering cases with daily precipitation of >150 mm occurring over southern France during autumn. Different diagnostics are used to document the time evolution of mesoscale features associated with the HPEs for initiation, mature, and dissipation stages. To underline differences according to the location of precipitation, four subdomains are also considered: Languedoc-Roussillon, Cévennes-Vivarais, South Alps, and Corsica. Composite analyses show that these events are driven by some common features (slowly evolving trough–ridge pattern and diffluent midlevel flow). Instability and moisture are transported by the low-level jet (LLJ) toward the target area from their sources, which are located upstream over the Mediterranean Sea. Strong moisture convergence is located within the left exit of the LLJ. These parameters reach a maximum during the mature stage. During the life cycle of the HPEs, the low-level winds rotate clockwise. Composite analyses also show that the synoptic and mesoscale patterns can differ greatly as a function of the location of the precipitation. Indeed, the LLJ varies from southeasterly to southwesterly. The midlevel flow varies from southerly to southwesterly. The areas of high moisture and instability are stretched in different orientations. Long-lasting events are associated with a more pronounced quasi-stationary trough–ridge pattern, higher values of CAPE, a wetter troposphere, and faster LLJ. The most-heavily precipitating events are found to be in general associated with higher values of these parameters or with a low-level inflow that is closer to perpendicular to the relief.},
  Booktitle                = {Journal of Applied Meteorology and Climatology},
  Copublication            = {3: 3 Fr},
  Doi                      = {10.1175/JAMC-D-11-017.1},
  ISSN                     = {1558-8424},
  Owner                    = {hymexw},
  Publisher                = {American Meteorological Society},
  Timestamp                = {2016.01.08},
  Url                      = {http://dx.doi.org/10.1175/JAMC-D-11-017.1}
}