Forecast sensitivity to Observation Carla Cardinali

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Forecast sensitivity to ObservationCarla
Cardinali
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Outline Part 2 Forecast Sensitivity

• Forecast Sensitivity to Observation
• Sensitivity gradient
• A-TReC campaigns
• Comparing Observation Analysis Influence and
  Observation Forecast Impact
• Results and Conclusion

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Forecast Sensitivity to Observation
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Define Forecast Sensitivity
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Change of Variable
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Computation
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Forecast Sensitivity to Observations
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Sensitivity Gradients
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Fc Sensitivity to Aircraft Temperature 500 hPa
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Fc Sensitivity to Surface Pressure
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Observation Campaign 5 Dec 18 UTC---Verification
7 Dec 12 UTC
TargetIN/NOTargetIN AMDAR 2.5 SONDE 5.5
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Observations Contribution to Forecast
Total Contribution
Mean Contribution
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Forecast and Analysis Sensitivity to Targeted
Observations
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200-300 hPa Targeted Aircraft Temperature
Forecast Error
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Aircraft Observation U-Comp 200-300 hPa
Observation Influence in Analysis
Background Influence 1-Observation Influence
Forecast Impact
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TEMP Observation Temperature 850-1000 hPa
Observation Influence in Analysis
Background Influence 1-Observation Influence
Forecast Impact
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Total Forecast Error 5 Dec 2003
TargetIN/NOTargetIN 8
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Observation Campaign 8 Dec 18 UTC---Verification
11 Dec 00 UTC
TargetIN/NOTargetIN AMDAR 2.6 SONDE 0.9
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200-300 hPa Targeted Aircraft U Forecast Error
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Total Forecast Error 8 Dec 2003
TargetIN/NOTargetIN 3.5
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Conclusions

• Forecast sensitivity to observations has been
  computed for the campaigns showing an impact
  (ATreC-Cntr)/Cntr 10
• 13 cases out of 38 9 positive and 4 negative
• Two campaigns have been shown
• 5 Dec at 18 UTC - Targeted observations improved
  the forecast of a cyclone moving along the east
  coast of North America for which severe weather
  impact was forecast
• 8 Dec at 18 UTC Targeted observations deployed
  to clarify the models uncertainties for the
  remnants of the east cost storm, degraded the
  forecast over Northern Europe UK
• However, differences in forecast impact between
  ATreC and Cntr come also from the continuous
  assimilation cycling that provides different
  model trajectories
• Forecast Impact computed for the cancelled
  campaigns gives on average 10 in term of RMSE
  in the verification area

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END
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Singular vectors brief definition

• Singular vectors was one of technique used in
  AtreC-TOST campaign to find sensitivity areas
  where releasing additional observations
• Singular vectors (SVs) define perturbations with
  fastest growth during a finite time interval
  (optimization time interval). They are defined
  by
• The model characteristics TL95L60, dry, with
  simplified physics
• The norm used to measure growth localized total
  energy
• The optimization time interval 42-54 hours
• Diagnostic Singular vectors have been computed to
  investigate the observation impact in the
  forecast

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