Impact of the backscatter kinetic energy on the perturbation of ensemble members for strong convective event Jakub Guzikowski Jakub Guzikowski meteoweb.pl

Introduction Global scale Mesoscale Synoptic scale Flow of energy in the atmosphere Microscale dissipation downscale upscale 2Jakub Guzikowski

Impact of simplified flow of the energy between mesoscale and microscale of-turbulence/#sthash.vBlAt9OP.vQqL7Zod.dpbs Vincent Van Gogh Starry Night - Kolmogorov scale (Petros Vrellis) Problems Convection Mountain drag Subgrid processes are smoothed n -5/3 inertial range power spectrum for wavelengths of less than 400 km (Durran and Gingrich, 2014) 3Jakub Guzikowski

Backscatter kinetic energy (SKEB) The crucial idea of SKEB is that energy is associated with sub – grid processes and is injected back onto the grid using a stochastic pattern generator. Generate temperature, u and v wind vector perturbations are added to the prognostic equation, at end of the dynamical time step, before being passed to the physical routines. Temperature U wind vector V wind vector x - zonal i y - meridional direction in physical space, t – time, Ψ’ - energy spectrum k=K+1 and l=L+1 wavenumber components - Fourier modes Details: Shutts, 2005; Berner et al. 2009; 2011; 2012; Berocal et al., ,Jakub Guzikowski

Configuration of the Ensemble Members WRF PhysicsSchemas MicrophysicsNew Thompson (Thompson et al., 2004) Boundary Layer MYJ (Janjic, 1994) Surface LayerNoah land surface model (Chen and Dudhia, 2001) Longwave Radiation Rapid radiative transfer model (Mlawer et al., 1997) Shortwave RadiationDudhia (Dudhia, 1989) Cumulus Parameterization Kain-Fritsch (Kain, 2004) for d01 i d02, lack of in d03 Horizontal resolution d01: ∆x = ∆y = 50 km; d02: ∆x = ∆y = 10 km; d03: ∆x = ∆y = 2 km Vertical resolution35 levels Main aspects: Perturbations by SKEB 9 members 5Jakub Guzikowski

Case study 23 – 31 July 2013 Heat wave (HW) in Poland from 23th to 29th July (Tropical dry stable air masses), in 29th advection of Tropical moist air masses, and occurrence of Mesoscale Convective System (MCS). 6 Verification 2m temperature data from 74 surface meteorology stations localized in Poland area, 3 h time resolution (points analysis) ERAINTERIM 0.75 x 0.75 degree horizontal resolution, 6 h time resolution (spatial analysis) NCEP FNL 1.0 x 1.0 degree horizontal resolution, 6 h time resolution (spatial analysis) Jakub Guzikowski

Results MAE and RMSE error statistics for individual ensemble members verifying by observations (OBS), Erainterim reanalysis data (ERA), NCEP FNL analysis (FNL) and control not perturbed model. 7Jakub Guzikowski

MAE and RMSE error statistics for raw ensemble system, verifying by observation (OBS), Erainterim reanalysis data (ERA), NCEP FNL analysis (FNL) and control not perturbed model. 8Jakub Guzikowski

Spatial localization of MAE and RMSE error statistics for first quantile verifying by observations, Erainterim reanalysis data NCEP FNL analysis and control not perturbed model. 9Jakub Guzikowski

Conclusion Implementation of the kinetic energy backscatter has positive impact on the perturbation of the 2m temperature data from the ensemble members. 10Jakub Guzikowski

Thank you 11Jakub Guzikowski Comments and questions are welcome

Grant IGF PAN No ; „Calculations have been carried out using resources provided by Wroclaw Centre for Networking and Supercomputing (wcss.pl), grant No. 170”. 12Jakub Guzikowski