R - University of Wisconsin MM5 Real Time Forecast and Forecast ...

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Impact studies or “what if?” experiments• Impact studies involve studying the effects a specificinitial and/or boundary perturbation (x 0 ) to an NWPmodel has on some aspect of a forecast.• While these perturbations are often chosen based on“synoptic intuition”, typically the precise choice of thelocation and structure of the imposed initialperturbations is not known.• The chosen perturbations may have very little impacton the weather system of interest.• As these studies are performed to assess theimportance of a particular synoptic feature, manyintegrations are needed to yield useful results.
Modeling System Used• MM5 Adjoint Modeling System (Zou et al. 1997)with non-linear model state vector:x = ( u,v,w,T,p', qv)• All sensitivities were calculated by integrating theadjoint model “backwards” using dry dynamics,about a moist basic state.• The corresponding adjoint model state vector is:∂R∂x∂R= (∂u∂R∂R∂R∂R, , , , )∂v∂w∂T∂p'
Page 1 and 2: Application and interpretation ofad
Page 3 and 4: Goals• Describe what an adjoint m
Page 5 and 6: Relationship between the nonlinear
Page 7: Application #1: Synoptic case studi
Page 11 and 12: Mean sea level pressure and tempera
Page 13: 36h temperature sensitivity evoluti
Page 17 and 18: ∂R∂u∂R∂v700 hPa sensitiviti
Page 19 and 20: 700 hPa sensitivity gradients valid
Page 21 and 22: Impact study of McTaggart-Cowan (20
Page 23 and 24: Initial state (250:300 hPa PV)
Page 25 and 26: Final state
Page 27 and 28: Application #2: Identification of
Page 29 and 30: Control and perturbed analyses
Page 31 and 32: VERIFYING ANALYSISDAY-5 FORECAST“
Page 33 and 34: Application #3: 4DVAR data assimila
Page 35 and 36: La CASsE STUDY1200 UTC 13 February
Page 37 and 38: Assimilation in sensitive regions12
Page 39: Questions?Real-time forecast sensit

R - University of Wisconsin MM5 Real Time Forecast and Forecast ...

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