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Atmosphere C oupling and Implications for Upper A tmosphere Predictability Han-Li Liu High Altitude Observatory National Center for Atmospheric Research. Talk partly based on:

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Talk partly based on:

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  1. Atmosphere Coupling and Implications for Upper Atmosphere PredictabilityHan-Li LiuHigh Altitude ObservatoryNational Center for Atmospheric Research Talk partly based on: Liu, H.-L., F. Sassi, and R. R. Garcia, Error growth in a whole atmosphere climate model, J. Atmos. Sci., 66, 173-186, 2009. Liu, H.-L. W. Wang, A.D. Richmond, and R.G. Roble, Ionospheric variability due to planetary waves and tides for solar minimum conditions, J. Geophys. Res., 115, A00G01, doi:10.1029/2009JA015188, 2010. 26-29 April, 2011 Space Weather Workshop

  2. Overview • Large-scale impact of lower atmosphere perturbations on the ionosphere/thermosphere • Interaction between planetary waves and tides. • Predictability of the upper atmosphere perturbations.

  3. ?

  4. Liu et al (2007)

  5. Wind Changes Due to A Quasi-Stationary Planetary Wave 250 250 200 200 150 150 Alt (km) Alt (km) 100 100 50 50 Stationary planetary wave 1 Migrating diurnal tide Migrating semi-diurnal tide Semi-diurnal westward wave 1 50 50 -50 -50 0 0 Lat. Lat. Liu et al., 2010

  6. Comparing Vertical Ion Drift (Solar Min)

  7. Temporal-Spatial Variability

  8. E and F Region Dynamo

  9. Observational Evidence of Ionospheric Response During SSW Goncharenko et al, 2010 Yue et al, 2010 afternoon morning

  10. Error Growth of WACCM Solid: Stratosphere Dashed: troposphere Dotted: MLT RMS difference (m/s) m/s Liu et al., 2009

  11. Scale Dependence of Error Growth

  12. Control of Error Growth • Error growth in the upper atmosphere is likely closely tied to decreasing skills in forecasting atmospheric waves. • We should be able to control error growth in the upper atmosphere if we have good knowledge of the wave sources. • WACCM Experiments: • “B” case: Base case (“truth”) • “A” case: Error in initial condition • “A(B,ps,DT)” case: A corrected with perfect knowledge of B at level ps every DT time.

  13. Control of Error Growth in the Upper Atmosphere A-B A(B,50hPa,20d)-B A(B,50hPa,5d)-B A(B,700hPa,24hr)-B A(B,500hPa,24hr)-B A(B,50hPa,24hr)-B Liu et al., 2009.

  14. Summary • Two related reasons why we should get the lower atmosphere waves right: • Planetary waves/tides from the lower atmosphere can affect the ionospheric variability. • The loss of forecasting skills of these waves is a major cause of error growth in the middle and upper atmosphere (in the absence of magnetic storms). • Accurate specification of the lower atmosphere state helps control the error growth of the middle and upper atmosphere.

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