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Impacts of Lower Atmosphere Perturbations on Upper Atmosphere Predictability

This presentation explores the significant influence of lower atmosphere perturbations on the predictability of the upper atmosphere. It discusses the complex interactions between planetary waves, tides, and their effects on the ionosphere and thermosphere, highlighting key findings from research conducted by Liu et al. (2007, 2009, 2010). The study emphasizes the importance of accurate lower atmosphere forecasting to control error growth in the upper atmosphere, suggesting that improved understanding of wave sources is essential for enhancing prediction skills.

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Impacts of Lower Atmosphere Perturbations on Upper Atmosphere Predictability

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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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