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 Davolio, S., Volonté, A., Manzato, A., Pucillo, A., Cicogna, A. and Ferrario, M.E.
Abstract:
During the first HyMeX Special Observation Period (SOP1) field campaign, the target site of North Eastern Italy (NEI) experienced a large amount of precipitation, locally exceeding the climatological values and distributed among several heavy rainfall episodes. In particular, two events that occurred during the last period of the campaign drew our attention. These events had common large-scale patterns and a similar mesoscale setting, characterised by southerly low-level flow interacting with the Alpine orography, but the precipitation distribution was very different. During IOP18 (31 October – 1 November 2012), convective systems were responsible for intense rainfall mainly located over a flat area of the eastern Po Valley, well upstream of the orography. Conversely, during IOP19 (4 – 5 November 2012), heavy precipitation affected only the Alpine area. In addition to IOP18 and IOP19, the present study analyses other heavy-precipitation episodes that display similar characteristics and which occurred over NEI during the autumn of recent years. A high-resolution (2-km grid spacing) non-hydrostatic NWP model and available observations are used for this purpose. The two different observed precipitation patterns are explained in terms of interaction between the impinging flow and the Alps. Depending on the thermodynamic profile, convection can be triggered when the impinging flow is forced to rise over a pre-existing cold-air layer at the base of the orography. In this situation persisting blocked-flow condition and upstream convergence are responsible for heavy rain localized over the plain. Conversely, if convection does not develop, flow-over conditions establish and heavy rain affects the Alps. Numerical parameters proposed in the literature are used to support the analysis. Finally, the role of evaporative cooling beneath the convective systems is evaluated. It turns out that the stationarity of the systems upstream of the Alps is mainly attributable to persisting blocked-flow conditions, while convective outflow slightly modifies the location of precipitation.
Reference:
Davolio, S., Volonté, A., Manzato, A., Pucillo, A., Cicogna, A. and Ferrario, M.E., 2016: Mechanisms producing different precipitation patterns over north-eastern Italy: insights from HyMeX-SOP1 and previous eventsQuarterly Journal of the Royal Meteorological Society, 142, 188-205.
Bibtex Entry:
@Article{Davolio2016,
  Title                    = {Mechanisms producing different precipitation patterns over north-eastern Italy: insights from HyMeX-SOP1 and previous events},
  Author                   = {Davolio, S. and Volont\'{e}, A. and Manzato, A., and Pucillo, A., and Cicogna, A. and Ferrario, M.E.},
  Journal                  = {Quarterly Journal of the Royal Meteorological Society},
  Year                     = {2016},

  Month                    = {August},
  Number                   = {S1},
  Pages                    = {188-205},
  Volume                   = {142},

  Abstract                 = {During the first HyMeX Special Observation Period (SOP1) field campaign, the target site of North Eastern Italy (NEI) experienced a large amount of precipitation, locally exceeding the climatological values and distributed among several heavy rainfall episodes. In particular, two events that occurred during the last period of the campaign drew our attention. These events had common large-scale patterns and a similar mesoscale setting, characterised by southerly low-level flow interacting with the Alpine orography, but the precipitation distribution was very different. During IOP18 (31 October – 1 November 2012), convective systems were responsible for intense rainfall mainly located over a flat area of the eastern Po Valley, well upstream of the orography. Conversely, during IOP19 (4 – 5 November 2012), heavy precipitation affected only the Alpine area. In addition to IOP18 and IOP19, the present study analyses other heavy-precipitation episodes that display similar characteristics and which occurred over NEI during the autumn of recent years. A high-resolution (2-km grid spacing) non-hydrostatic NWP model and available observations are used for this purpose.
The two different observed precipitation patterns are explained in terms of interaction between the impinging flow and the Alps. Depending on the thermodynamic profile, convection can be triggered when the impinging flow is forced to rise over a pre-existing cold-air layer at the base of the orography. In this situation persisting blocked-flow condition and upstream convergence are responsible for heavy rain localized over the plain. Conversely, if convection does not develop, flow-over conditions establish and heavy rain affects the Alps. Numerical parameters proposed in the literature are used to support the analysis.
Finally, the role of evaporative cooling beneath the convective systems is evaluated. It turns out that the stationarity of the systems upstream of the Alps is mainly attributable to persisting blocked-flow conditions, while convective outflow slightly modifies the location of precipitation.},
  Copublication            = {6: 6 It},
  Doi                      = {10.1002/qj.2731},
  Owner                    = {hymexw},
  Timestamp                = {2016.08.26},
  Url                      = {http://onlinelibrary.wiley.com/doi/10.1002/qj.2731/abstract}
}