Relationships between total lightning activity, microphysics, and kinematics during the 24 September 2012 HyMeX MCS system J.-F. Ribaud, O. Bousquet and S. Coquillat Ribaud, J.-F., O. Bousquet, S. Coquillat, H. Al-Sakka, D. Lambert, V. Ducrocq, E. Fontaine, Evaluation and application of hydrometeor classification algorithm outputs inferred from multi-frequency dual-polarimetric radar observations collected during HyMeX. Q.J.R. Meteorol. Soc., 2015, Ribaud, J.-F., O. Bousquet, S. Coquillat, Relationships between total lightning activity, microphysics, and kinematics during the 24 September 2012 HyMeX bow echo system. Submitted to Q.J.R. Meteorol. Soc., April th HyMeX Workshop Mykonos, September /13

1)Influence of cloud microphysics and dynamics on lightning propagation and initiation? 2)Impact of the topography on lightning activity ? Objectives Reflectivity compositeHyLMA 200 km Studied area 9th HyMeX Workshop Mykonos, September /13

Lightning observation  EUCLID-Météorage CG network  12 LMA stations (Ø 100 km) 3D mapping of lightning (Ø 600 km) MHz VHF sources 80 µs resolution (x, y, z, t) by TOA technique 9th HyMeX Workshop Mykonos, September /13 VHF sources density Domain corresponding to the resolution of interpolated radar data

3-dimensional reflectivity and wind composite  Météo France operational Doppler radars  MUSCAT (Bousquet & Chong,1998)  Horizontal reflectivity (Z H )  Wind components (u,v,w)  Available every 15 minutes  Resolution 1km x 1km x 0.5km 4/13 9th HyMeX Workshop Mykonos, September 2015

Z = 2 km Ribaud et al, dimensional hydrometeor composite  Dual polarimetric radars of Météo France  Available every 15 minutes  Resolution 1km x 1km x 0.5km  Fuzzy logic hydrometeor classification  6 microphysical species: Stratiform Rain Wet Snow Dry Snow Ice 9th HyMeX Workshop Mykonos, September 2015 Convective Rain Graupel Hail Ice 5/13 Horizontal reflectivityDifferential reflectivity Differential phaseCorrelation coefficient

9th HyMeX Workshop Mykonos, September /13 Lightning activity during 24 September 2012 Weak activity Strong IC activity 00:3001:3002:3003:30Time UTC

9th HyMeX Workshop Mykonos, September /13 1 st period 2 nd period 3 rd period Z h at 5 kmVHF sources Z h, wind, VHF sourcesMicrophysics, VHF sources

9th HyMeX Workshop Mykonos, September /13 1 st period 2 nd period 3 rd period Z h at 5 kmVHF sources Z h, wind, VHF sourcesMicrophysics, VHF sources

9th HyMeX Workshop Mykonos, September /13  Ice particules transport in the stratiform region  Branching of lightning on those charged ice particles  VHF signature of this transport  Dynamical evidence of ice particles transport in the stratiform region  VHF signature of charged particles away from the convective updraft  Lessening of the electric charge in the convective updraft  Decrease in local electric field (triggering of lightning less favourable)  Decrease in lightning activity Z h, wind, VHF sourcesMicrophysics, VHF sources Carey et al., 2005, JGR Ely et al., 2008, JGR 2 nd period VHF sources density 2 nd period

km AMSL 2 nd period 3 rd period 9th HyMeX Workshop Mykonos, September 2015  Strong hail concentration increase during 2 nd and 3 rd periods  Large lightning holes at 5 km AMSL during 2 nd period  Wet growth of hail could lessen the electrification processes  Consistent with Payne et al. (2010) and Emersic et al. (2011)  Could contribute to the low lightning activity of the 2 nd period 10/13

9th HyMeX Workshop Mykonos, September /13 Lightning activity within the most active cell Strong IC activity 02h45 – 03h00

9th HyMeX Workshop Mykonos, September /13  Highest updraft speed  Ice particles and graupel at high altitude  Numerous VHF sources at high altitude 15 minutes after the passage over the hill Evidence for orographic forcing 02h45 – 03h00

Conclusion  Analyzing this event by means of lightning observation allows detecting dynamical and microphysical processes inside the cloud  The use of modeling could confirm the hypothesis put forward in this case  Important part played by dynamics and microphysics inside the storm for controlling the electrical activity  Influence of topography on convection and consequently on lightning activity (small hill highly influences the lightning activity within the convective core)  Microphysics associated with lightning propagation and initiation are mainly graupel and ice particles (consistent with the non inductive charging mechanism)  Lightning most often initiated in graupel regions 13/13 9th HyMeX Workshop Mykonos, September 2015  Evaluate the performance of explicit numerical lightning scheme such as CELLS (Barthe et al. 2012, Pinty et al. 2013)  Improve the performance of hydrometeor classification algorithm from dual-polarization radar. Potential of VHF sources location for graupel and ice particles? Work to be done

VHF sources vs microphysics: first quantification VHF source Initial breakdown Grid box 9th HyMeX Workshop Mykonos, September 2015 Lightning propagation takes place mainly in graupel (58%) and ice (33%) regions  Lightning is most often initiated in graupel (70%) and a less extent in ice (22%) regions 

- Electrification preferentially in convective regions - Discharge favoured by reduced pressure - Better detection of upper negative leaders Z h at 5 km VHF sources 1 st period 2 nd period 3 rd period 9th HyMeX Workshop Mykonos, September 2015 Particles involved in lightning propagation, and more especially in lightning initiation, are the "highest" of all particles in each category

Jean-François RIBAUD Météo-FranceLMA / Microphysique / Dynamique / HyMeX Les radars à double diversité de polarisation Z H et Z V → indication sur la taille des hydrométéores Z DR → indication sur la forme des hydrométéores Φ DP → estimation de l’atténuation K DP → indication sur la densité d’hydrométéores ρ HV → indication sur le type d’hydrométéore Il est donc possible de retrouver le type dominant dans une porte radar 12/32 IntroductionMéthodologieRésultatsConclusionsContexteInstruments Radar

Jean-François RIBAUD Météo-FranceLMA / Microphysique / Dynamique / HyMeX Le typage d’hydrométéores à partir des radars DPol 13/32 IntroductionMéthodologieRésultatsConclusionsContexteInstruments