and NM Tech team & many HyMeX participants Explicit simulations in a mesoscale model of electrified clouds observed by a LMA during HyMeX-SOP1 experiment J.-P. Pinty(1), C. Bovalo(1), E. Defer(2), E. Richard(1), P. Krehbiel(3), W. Rison(3), R. Thomas(3) and NM Tech team & many HyMeX participants (1) Lab. Aérologie, Toulouse,, France (2) LERMA, Observatoire de Paris France (3) New Mexico Tech., Socorro, USA Motivations: High-quality observations of the cloud electrical activity with a LMA(*) during the HyMeX SOP1 field experiment (Fall 2012) Simulation of real cases to evaluate the explicit «electrical» module of MesoNH by comparison with LMA lightning data (*) LMA: Lightning Mapping Array is manufactured by the New Mexico Tech., Socorro, NM 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

9th HyMeX workshop, Mykonos, Greece, Sept, 2015 Outlines of the presentation Short overview of the electrical scheme used to simulate real electrified clouds with MesoNH: focus on the links between cloud physics and cloud electricity Simulations of meteorological «HyMeX» cases: Sept, 5th (isolated convection) and Sept, 26th, (moderate precip event) over the Cévennes area in the South of France and sensitivity experiments for the Sept, 24th case (IOP6). Ref: Barthe et al., GMD, 2012; Pinty et al., AR, 2012; Defer et al., AMT, 2015 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical scheme of MesoNH 3 CRM (Mansell et al., 2002; Barthe et Pinty, 2007; Fierro et al., 2013) with a complete explicit 3D electrical scheme. electrical charges + electric field + lightning flashes ||E||>Etrig Numerical method Coupling with cloud μphysics (NI charging process TAKAH/SAUND) and physics of the ions Conceptual model leaders & branches  Partial charge neutralization (Eq. is solved for with I and BC) Continuous charging (μphysics) Discrete discharging (flashes) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical charging rate vs Mass growth rate (1) r: mixing ratio, q: electrical charge (bulk quantities) Transfer terms, i.e. riming, melting  parametric model Sedimentation  analytical integration is provided by physics where Vx is the fall speed  Charge separation at cloud scale (at the origin of E) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical charging rate vs Mass growth (2)  Charge separation at micro-scale (at the origin of qx) Non-Inductive charging  physical model with 3 types of «ice-ice» interactions (ICE3 scheme) where Kxy is the collision kernel 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical charging rate vs Mass growth (2) Jayaratne et al. (1983) Takahashi (1978) Saunders & Peck (1998) Saunders et al. (1991)  Charge separation at micro-scale (at the origin of qx) Non-inductive charging  physical model with 3 types of «ice-ice» interactions (ICE3 scheme) Look-up tables or Expressions (LWC,T) where Kxy is the collision kernel 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical charging rate vs Mass growth (2) Jayaratne et al. (1983) Takahashi (1978) Saunders & Peck (1998) Saunders et al. (1991)  Charge separation at micro-scale (at the origin of qx) Non-inductive charging  physical model with 3 types of «ice-ice» interactions (ICE3 scheme) Look-up tables or Expressions (LWC,T) where Kxy is the collision kernel Exy: collection efficiency  r 1-Exy: rebounding efficiency  q 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Electrical charging rate vs Mass growth (2) Jayaratne et al. (1983) Takahashi (1978) Saunders & Peck (1998) Saunders et al. (1991)  Charge separation at micro-scale (at the origin of qx) Non-inductive charging  physical model with 3 types of «ice-ice» interactions (ICE3 scheme) Look-up tables or Expressions (LWC,T) where Kxy is the collision kernel Exy: collection efficiency  r 1-Exy: rebounding efficiency  q NO Non-Inductive charging when hail is involved explicitly (4 types of ice particles: ICE4 scheme) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

Known uncertainties when simulating explicitly the electrical state of the clouds CHARGING PHASE Tuning of the parent microphysical scheme : 3-4 ice particle types and amount of supercooled water Choice of the adequate charge separation diagram qxy as several diagrams are available from lab. experiments DISCHARGING PROCESS Choice of the fractal dimension to represent the spread of the flashes (in our electrical scheme CELLS) Selection of IntraCloud vs Cloud-to-Ground flashes  HyMeX LMA dataset to test the electrical scheme 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 05 Sept. 2012 Case Synoptic situation (Low-level situation at 15 UTC, after 9 h run from 20120905_06UTC AROME analysis) Grid-nested simulation: 192x192 gridpoints @ 4km and 384x384 gridpoints @ 1km 950 hPa equiv. Pot. Temp. and Wind Radar (dBZ) at z=2000m Massif Central (4 km horiz. resolution) Alps Reflectivity composite Pyrenees 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 5 Sept. 2012 Case: 15:00-21:00 RADAR Observation 6 hour RESTART with ELEC scheme 15:00 16:00 17:00 18:00 19:00 RADAR Grid-nested simulation: 192x192 gridpoints @ 4km and 384x384 gridpoints @ 1km Observation Simulation: 384x384 gridpoints @1km FLASHES « Montpellier » storm Spurious cells LMA flashes (color) and EUCLID impacts (black) IC cover (color) and CG impacts (black) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 5 Sept. 2012 Case Close view of “Montpellier” storm Data Simulation LMA & EUCLID data IC density & IC trig. locations Simulation: + accurate location and duration of the storm + flash rate (SAUN2 & SAP98) - lack of CG 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 5 Sept. 2012 Case Electrical charges : 05 Sept 17:45 +2nC/kg Pristine ice High & Low level flashes -2nC/kg +2nC/kg Snow-Aggr.  Tripole charge structure -2nC/kg Total charge & ||E|| Graupel +2nC/kg -2nC/kg +2nC/kg Rain ||E|| max ~ 100 kV/m -2nC/kg LMA & EUCLID data 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 5 Sept. 2012 Case Electrical state at ground level Charge of the raindrops +2nC/kg -2nC/kg Electric field: Ez +10kV/m +1kV/m -1kV/m -10kV/m Ground Level LMA & EUCLID data 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 26 Sept. 2012 Case Synoptic situation (Low-level situation at 04 UTC, after 4 h run from 20120926_00UTC AROME analysis) Grid-nested simulation: 192x192 gridpoints @ 4km and 384x384 gridpoints @ 1km 950 hPa equiv. Pot. Temp. and Wind Radar (dBZ) at z=2000m Alps Massif Central (4 km horiz. resolution) Precip rate (mm/h) at GL Pyrenees (4 km horiz. resolution) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 26 Sept. 2012 Case Rainfall (log scale) 8 hours RESTART with ELEC scheme {26 Sept 04:00}-{26 Sept 12:00} Max=89 mm (Ardèche) MesoNH: Max=76 mm 8 h grid-nested run with explicit «Electricity» module Initial state = 4 h model run from 20120926:00UTC «Arome» analysis 4-km 3-h External Lateral forcing with «Arome» analyses (at 2.5 km) 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 26 Sept. 2012 Case ELEC results MesoNH: 00-04 then 04-12 with ELEC Grid-nested simulations: 192x192 gridpoints @ 4km and 384x384 gridpoints @ 1km 05:30 07:00 08:30 10:00 11:30 LMA data 04-12 26 Sept. 2012 CASE MesoNH: 00-04 then 04-12 with ELEC TAKAH: 5734 IC, 1093 CGN SAUND: 2893 IC 396 CGP SAP98 : 506 IC 241 CGP 3030 fl. EUCLID 2178 fl. 04:00 - 12:00 TRIG. Loc. 04:00 - 12:00 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 26 Sept. 2012 Case ELEC results MesoNH: 00-04 then 04-12 with ELEC Grid-nested simulations: 192x192 gridpoints @ 4km and 384x384 gridpoints @ 1km 05:30 07:00 08:30 10:00 11:30 LMA data 04-12 26 Sept. 2012 CASE MesoNH: 00-04 then 04-12 with ELEC TAKAH: 5734 IC, 1093 CGN SAUND: 2893 IC 396 CGP SAP98 : 506 IC 241 CGP Red color means CGP 3030 fl. EUCLID 2178 fl. 04:00 - 12:00 TRIG. Loc. 04:00 - 12:00 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

The 24 Sept. 2012 Case a sensitivity study (6 hours) ICE3 Precip Reference simulation ICE3 Additional simulations: ICE4 : 4 categories of ice (hail) and flash fractal dimension 2.0<<2.5 Flash observation: 13,138 (LMA) and 20,917 (Euclid) 6h Precip Number of flashes Simulation TAKAH SAUND SAP98 ICE3 13,748 ICE4 12,293 7,861 3,801 =2.0 20,122 =2.5 11,788 ICE4 Precip  Less flashes when hail is considered explicitly and when the flash fractal dimension is increased 9th HyMeX workshop, Mykonos, Greece, Sept, 2015

9th HyMeX workshop, Mykonos, Greece, Sept, 2015 Conclusion The electrical module CELLS of the Cloud-Resolving Mesoscale Model MesoNH is able to simulate explicitly 3D electrified clouds on multiprocessor computers over complex terrain at km scale for several hours The meteorological «HyMeX» simulations are encouraging for an evaluation of the scheme against LMA data (and other lightning detection networks). The accuracy of the convective cells location is a first limitation but simulations with Saunders et al., (1991) separation rate seem to perform the best LMA data: total flash count, flash horizontal extension, polarity of the cloud layers, triggering & propagation altitudes, etc. are useful features to check in the model Perspectives of the modeling work in cloud electricity: The electrical scheme was run intensively for many «HyMeX» cases encompassing the LMA network for data comparison  work to do: to check carefully the 3D electrical state of the simulated clouds to improve the IC/CG flash selection criteria for better results 9th HyMeX workshop, Mykonos, Greece, Sept, 2015