shadowing in the atmosphere ross lieb-lappen chris danforth
Post on 19-Dec-2015
219 views
TRANSCRIPT
Forecasting Challenges
• Uncertainty in the initial state
• Chaos: sensitive dependence on initial conditions
• Model error
Forecasting Methodology
• Ensemble forecasting
• Lorenz ‘96 Model
• Define new ensemble members
• Inflation of forecast ellipsoid
FXXXXdtdX jj jjj 121 )(/
advection dissipation
external forcing
Controlled Inflation• Only in contracting directions • Within climatological span of particular variable
• Maintain appropriate ratio with neighboring values
Model Success
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
Time
Err
orDifference between Truth and Forecast