Research at ECMWF concerning the simulation of the Madden - Julian Oscillation Adrian Tompkins Peter Bechtold, Judith Berner, Laura Ferranti, Thomas Jung, Frederic Vitart, Nils Wedi. Diagnosing the MJO in the ECMWF forecast system Research and model changes to improve the MJO prediction
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Research at ECMWF concerning the simulation of the Madden - Julian OscillationAdrian TompkinsPeter Bechtold, Judith Berner, Laura Ferranti, Thomas Jung, Frederic Vitart, Nils Wedi
850hPA Zonal Wind
NCEP reanalysis ECMWF operational Analysis
Signal visible in unfiltered data
Operations 24hr forecast
Tomorrow will see scattered showers in the north… and in the south there will be some MJO
200 hPa Velocity Potential anomaly
Vitart et al. 2003:
MJO variance decreases during the first 10d by as much as 50%
Spectral Analysis of 40 Winter Integrations
Model: IFS CY28R3
Q: Is there a crucial physically process (feedback) missing in the model or are waves being damped?
Develop of a multi-scale cellular automaton (MSCA) for organized convection that captures the subgrid-scale forcing not represented by conventional parameterizations.
Stochastic super clusters (SSC) as part of organized convection (super-gridscale)
Cartoon of idealized forcing pattern
200hPA Velocity Potential for 6 month Forecast
Work in Progress: But clear impact on propagating signals
Average for Ensemble of forecasts
mean wind oscillation
enforced in the tropics
Control: No 50 day peak.
Also Work in Progress
Amalgation of 10day forecasts: Velocity potential at 200 hPa
30r1 Current operations
30r2 Summer 2006
Impact on monthly forecast less dramatic
Velocity Potential at 200 hPa.Forecast starting on 31 December 1992
Increase entrainment into convection parametrized updraughts
Instead of enhancing parametrized convection in moist areas and supressing in dry areas..
…the scheme is supressed and the grid-scale takes over!!!
Increasing gridscale activity
Increasing power in convectively coupled mode
Normalized Peak Power of 200 hPa Vel Pot
Large Scale Circulation
Large Scale Circulation
Linking the convective parametrization mass-flux closure to mid-tropospheric motion as well as CAPE strengthens propagating modes
200 hPa Velocity Potential Anomaly
Grid-scale rainfall anomaly
Parametrization rainfall anomaly
That’s all, thank you!
T159 versus T95