First results from the HyMeX-SOP1 field campaign dedicated to Mediterranean heavy precipitation and flash-floods Véronique Ducrocq (CNRM-GAME, Météo-France, Toulouse, France) with contributions from: F. Bouttier, F. Duffourg, O. Nuissier, B.Vié, B. Vincendon (CNRM-GAME) S. Davolio (CNR-ISAC), J. Delanoë (IPSL/LATMOS), R. Ferretti (Univ. D’Aquilla), C. Flamant(IPSL/LATMOS), V. Homar (UIB), J.P. Pinty (LA) WWOSC2014, Montréal, August 2014

Introduction  HyMex is a 10-y program devoted to the water cycle in Mediterranean, with emphases on the predictability and evolution of hydrometeorological risks  Within the long-term observation period started in 2010, several special observation periods (SOP= research field campaigns) are performed for improving our knowledge about high-impact weather events in order to better understanding, modelling and forecasting them.  The first SOP series in Northwestern Mediterranean: -Heavy precipitation event (HPE) and flash-flooding for SOP1 (5 Sept.-6 Nov. 2012) -Regional winds, air-sea fluxes and ocean convection for SOP2 (1 Feb.-15 March 2013) France Spain Italy Mediterranean Sea

V. Ducrocq On large scale and mesoscale environment: Nuissier, O., Joly, B., Joly, A., Ducrocq, V. and Arbogast, Ph., 2011 (QJRMS); Ricard, D., V. Ducrocq, L. Auger, 2012 (JAMC) On triggering mechanisms: Ducrocq, V., O. Nuissier, D. Ricard, C. Lebeaupin, T. Thouvenin, 2008 (QJRMS); Bresson, E., V. Ducrocq, O. Nuissier, D. Ricard, C. de Saint-Aubin, 2012 (QJRMS) On water vapour origin and transport: Duffourg, F. and Ducrocq, V., 2011 (NHESS); Duffourg, F., and V. Ducrocq, 2013 (ASL) Heavy precipitation A multiscale phenomenom

SOP1 objectives 25 oct SOP1 aimed to obtain detailed information on four key components: The distributed hydrological response of the Mediterranean watersheds the microphysics and dynamics of precipitating systems leading to HPE the air-sea exchanges and ocean mixed layer prior and during HPE the upstream marine flows and their interaction with complex terrain

A large field campaign over the whole Northwestern Mediterranean Mobile or on-alert instrumented plaforms (atmosphere, ocean, soils and rivers) SOP1 experimental set-up ~200 instruments deployed for the field campaign, including airborne and seaborne instruments, radars, lidars, wind profilers, boundary layer balloons, etc – (~ 250 flight hours with SAFIRE/F20 & ATR42, KIT/DO128, ~850 RS) ~300 scientists involved in the field campaign Ducrocq et al, 2014 (BAMS)

Maximum of daily precipitation at each raingauge during SOP1 (5 Sep.-6 Nov. 2012) Ducrocq et al, 2014 (BAMS) SOP1 Intense Observation Periods (IOP) 20 days with at least one raingauge with more than 100mmm/24h 16 IOPs dedicated to Heavy precipitation Flood in Spain 13 fatalities Tornado in Marseille, Nice airport closed IOP13 IOP8 IOP16a Flood in France 2 Vergeiner Squall Lines in Italy IOP6 Ducrocq et al, 2014 (BAMS)

HyMeX SOP1 data exploitation HyMeX SOP1 data and more generally HyMeX observations provide the framework to :  Progress on the understanding of heavy precipitation events and on the hydrological processes during flash-floods.  Improve Convection-Permitting NWP, including physical (microphysics, turbulence) parameterizations, air-sea coupling, EPS and data assimilation systems.  Develop and evaluate the coupling of the new convection-permitting EPS with hydrological models for ensemble forecasting of flash-floods over the small-to- medium watersheds.  Evaluate and improve existing operational observation networks and associated products and of new observation systems and allow preparation for future satellite missions such the NASA GPM mission.  Evaluate coupled ocean-atmosphere-rivers regional climate modeling systems used in the joint HyMeX and WCRP/(MED-)CORDEX CMIP5 downscaling exercise over the Mediterranean domain.  Investigate the social and economical responses to extreme precipitation and associated hydrological events using among other approaches, an interdisciplinary post-flood methodology.

HyMeX SOP1 data exploitation HyMeX SOP1 data and more generally HyMeX observations provide the framework to :  Progress on the understanding of heavy precipitation events and on the hydrological processes during flash-floods.  Improve Convection-Permitting NWP, including physical (microphysics, turbulence) parameterizations, air-sea coupling, EPS and data assimilation systems.  Develop and evaluate the coupling of the new convection-permitting EPS with hydrological models for ensemble forecasting of flash-floods over the small-to- medium watersheds.  Evaluate and improve existing operational observation networks and associated products and of new observation systems and allow preparation for future satellite missions such the NASA GPM mission.  Evaluate coupled ocean-atmosphere-rivers regional climate modeling systems used in the joint HyMeX and WCRP/(MED-)CORDEX CMIP5 downscaling exercise over the Mediterranean domain.  Investigate the social and economical responses to extreme precipitation and associated hydrological events using among other approaches, an interdisciplinary post-flood methodology.

HyMeX SOP1 provides obs. to characterize the upstream flow over the sea where routine obs. are scare e.g. to investigate both the misrepresentation of Po Valley convection and over the sea by WRF (3km) evidenced over some IOPs. E. Pichelli, R. Rotunno, R. Ferretti, 2014 (in preparation) IOP6 – 24 Sept 2012 KIT/DO128 aircraft Low and mid-level specific humidity over the sea 23:50-03:00 UTC12:00-15:00 UTC Boundary layer pressurized balloon Use of HyMeX observations for understanding model deficiences Qv (g/kg) Qv (g/kg) Obs. WRF

MESO-NH – 2.5km model RASTA Radar reflectivities (dBZ) time (h) Composite radar reflectivities (dBZ) observed at 13:45 UTC and F20 trajectory Radar reflectivities (dBZ) simulated at 2000m at 12:45 UTC and F20 trajectory Stratiform part Convective part Images of hydrometeors F. Duffourg, O. Nuissier, J. Delanoë, A. Schwarzenbock2014 (in preparation) Use of HyMeX observations for validating and improving model parameterizations HyMeX SOP1 provides in-situ microphysical observations and radar onboard SAFIRE/F20, aerosols observations onboard SAFIRE/ATR42 in and near MCS e.g. in order to validate and improve microphysical parameterizations IOP16a – 26 Oct 2012 SAFIRE/F20 Aircraft

MESO-NH – 2.5km model RASTA Radar reflectivities (dBZ) time (h) Composite radar reflectivities (dBZ) observed at 13:45 UTC and F20 trajectory Radar reflectivities (dBZ) simulated at 2000m at 12:45 UTC and F20 trajectory F. Duffourg, O. Nuissier, J. Delanoë, A. Schwarzenbock2014 (in preparation) Use of HyMeX observations for validating and improving model parameterizations HyMeX SOP1 provides in-situ microphysical observations and radar onboard SAFIRE/F20, aerosols observations onboard SAFIRE/ATR42 in and near MCS e.g. in order to validate and improve microphysical parameterizations SAFIRE/F20 Aircraft Ice water content (g/m 3 )

12 Southeastern France, 12-h accumulated precipitation (mm), 2012/09/24, 12 UTC Raingauge observations Default aerosol populationMACC aerosols as IC and BC Use of HyMeX observations for validating and improving model parameterizations IOP6 – 24 Sept 2012 Validation of the LIMA 2-moment, mixed-phase microphysical scheme (Meso-NH)

Improved observation coverage from HyMeX SOP1 nb of obs per day per 1°x1° routine 3h-precip obs at Meteo-France HyMeX SOP1 obs density Use of HyMeX observations for convection-permitting EPS evaluation eg evaluate the future Météo-France AROME EPS (2.5 km, operational in 2015)

Reliability of the AROME-2.5km ensemble for high precipitation (rr3>20mm) suffers less from sampling error if verified against HyMeX SOP1 obs (thanks to 4x more high- precip obs in HyMeX than in routine dataset)  HyMeX allows optimisation of EPS for high precip events Reliability diagnosis using routine Météo-France obs using HyMeX SOP1 obs Use of HyMeX observations for convection-permitting EPS evaluation Bouttier et al, 2014 (in preparation) AROME EPS : perturbations of initial, lateral boundary conditions, surface, physics tendencies / 12 members, 1x/day during SOP1

25 oct. 26 oct. 27 oct. 28 oct. MF AROME EPS ARPA-EMR COSMO_H2 EPS  Discharge from ISBA-TOP hydrological model for the Ardèche catchment (South France) Obs. Using radar QPE Q25%-Q75% Mean IOP16a  Cumulative hourly area average precipitation over the Gualentin catchment (SE Spain) WRF EPS: Dynamical downscaling of ECMWF-EPS - 50 members IOP8 Obs. Probability-matched Mean Hydrological evaluation of convection-permitting EPS

More about HyMeX studies at WWOSC2014: Monday - SCI-PS137.03: AROME-WMED, a real-time mesoscale model designed for the HyMeX Special Observation Periods, N. Fourrié et al - SCI-PS144.02: Sensitivity study of a heavy precipitating event to the sea state using convection- permitting model simulations, O. Thévenot et al Tuesday - SCI-PS155.03: Western Mediterranean Sea air-sea exchanges from the AROME-WMED model during the HyMeX campaign, R. Rainaud et al - SCI-PS180.03: Mediterranean moisture supply during an extreme precipitation event in the north-western Mediterranean, J. Campa - SCI-PS180.04: Model studies of heavy precipitation events in the western Mediterranean during the HyMeX campaign (2012), L. Röhner Wednesday - SCI-PS228.01: An ensemble study of HyMeX IOP6 and IOP7a, E. Richard et al - SCI-PS228.03: Amplification of high precipitation in the Western Mediterranean by Corsica island flow and convection, U. Corsmeier et al - SCI-PS218.04: Large-scale surface wind extremes in the Mediterranean, S.Raveh-Rubin et al - SCI-POW1173: Moisture transport between Atlantic and Mediterranean regions leading to extreme precipitation and flooding event, J.Campa et al - UAS-PS330.03: Flash flooding and the global environmental change perspective: Toward an integrated strategy for disaster reduction, I. Ruin et al … and on Other examples of HyMeX dataset use

 The observations collected by more than 200 research instruments during SOP constitute an unprecedented dataset and unique relative to previous field experiments in the region as the atmosphere, ocean, river and soils were sampled together that are currently exploited in many on-going studies.  More than 350 datasets archived in the HyMeX database to support research on process understanding and model evaluation and improvement:  Measurements over the instrumented watersheds and social and hydrological post-event survey continue during the HyMeX Enhanced Observation Period (EOP) through the end of 2015 to capture additional flood events. Conclusion

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