Jakub Guzikowski

Impact of the backscatter kinetic energy on the perturbation of ensemble members for strong

convective event

Jakub Guzikowski(jguzikowski@igf.edu.pl)

meteoweb.pl

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Introduction

Global scale

Mesoscale

Synoptic scale

Flow of energy in the atmosphere

Microscaledissipation

downscale

upscale

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Impact of simplified flow of the energy between mesoscale and microscale

http://thegrumpyowl.com/2012/02/22/van-gogh-painted-deep-math-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)

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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 spectrumk=K+1 and l=L+1 wavenumber components - Fourier modes

Details: Shutts, 2005; Berner et al. 2009; 2011; 2012; Berocal et al., 2011,Jakub Guzikowski

Jakub Guzikowski

Configuration of the Ensemble Members

WRF Physics SchemasMicrophysics New Thompson (Thompson et al., 2004)

Boundary Layer MYJ (Janjic, 1994)

Surface Layer Noah land surface model (Chen and Dudhia, 2001)

Longwave Radiation Rapid radiative transfer model (Mlawer et al., 1997)

Shortwave Radiation Dudhia (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 resolution 35 levels

Main aspects:• Perturbations by SKEB• 9 members

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Jakub 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).

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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)

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ResultsMAE 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.

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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.

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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.

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Conclusion

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

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Thank you

Comments and questions are welcome

Jakub Guzikowski

• Grant IGF PAN No 500-10-9;

• „Calculations have been carried out using resources provided by Wroclaw Centre for Networking and Supercomputing (wcss.pl), grant No. 170”.

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