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
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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 Julian Oscillation
NCEP reanalysis ECMWF operational AnalysisMJO previous work
Signal visible in unfiltered data
GPCP Precipitation Julian Oscillation
Operations 24hr forecast
Tomorrow will see scattered showers in the north… and in the south there will be some MJO
1 Julian Oscillationst FebAnd the latest forecast from 2nd March 2006 is…
200 hPa Velocity Potential anomaly
1 Julian Oscillationst FebWell, a bit of an anticlimax to be honest…
1 Julian Oscillationst Feb850 hPa Zonal Wind Anomaly
Vitart et al. 2003:
MJO variance decreases during the first 10d by as much as 50%
ERA40-Reanalysis Julian Oscillation
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.
Cartoon of idealized forcing pattern
200hPA Velocity Potential for 6 month Forecast convection (super-gridscale)
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
Era 40 mean flow, influenced by the extra-tropics?2(c): Changes for 30R2 (summer 2006)
Amalgation of 10day forecasts: Velocity potential at 200 hPa mean flow, influenced by the extra-tropics?
30r1 Current operations
30r2 Summer 2006
Impact on monthly forecast less dramatic mean flow, influenced by the extra-tropics?
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 mean flow, influenced by the extra-tropics?Increasing Large-scale activity increases peak power (K=1,2,3 15 days<p<120 days)
Increasing power in convectively coupled mode
Normalized Peak Power of 200 hPa Vel Pot
Large Scale Circulation
Large Scale Circulation
EOF1 mean flow, influenced by the extra-tropics?
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!
Coupling mean flow, influenced by the extra-tropics?
T159 versus T95