Simulating the extratropical response to the Madden-Julian Oscillation

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Simulating the extratropical response to the Madden-Julian Oscillation. Hai Lin RPN-A, Environment Canada International S2S Conference, College Park February 10-13, 2014. Introduction. MJO Global impact (boreal winter): NAO (Lin et al 2009); PNA (Mori and Watanabe 2008) - PowerPoint PPT Presentation

Text of Simulating the extratropical response to the Madden-Julian Oscillation

  • Simulating the extratropical response to the Madden-Julian OscillationHai LinRPN-A, Environment Canada

    International S2S Conference, College Park February 10-13, 2014

  • IntroductionMJO Global impact (boreal winter): NAO (Lin et al 2009); PNA (Mori and Watanabe 2008) AO (LHeureux and Higgins 2008) Canadian temperature (Lin and Brunet 2010) Canadian precipitation (Lin et al 2010) Atmospheric response to MJO forcing: Matthews et al. (2004) Lin et al. (2010) Seo and Son (2012)

  • OutlinesIntroductionNumerical experiments: Dependence on heating location Nonlinearity Dependence on initial condition Summary

  • Correlation when PC2 leads PC1 by 2 pentads: 0.66Lin et al. (2010)

  • Normalized Z500 regression to PC2Lin et al. (2010)

  • Model and experimentPrimitive equation AGCM (Hall 2000) similar configuration of model forcing as the Marshall-Molteni model, but not Q-G.T31, 10 levelsTime-independent forcing to maintain the winter climateLinear integration, winter basic state

  • Thermal forcingExp1 forcingExp2 forcingLin et al. (2010)

  • Z500 responseExp1Exp2Lin et al. (2010)

  • Linear integration, winter basic statewith a single center heating source Heating at different longitudes along the equator from 60E to 150W at a 10 degree interval, 16 experiments Z500 response at day 10

    Why the response to a dipole heating is the strongest ?

  • Day 10 Z500 linear response80E110E150ESimilar pattern for heating 60-100ESimilar pattern for heating 120-150W

  • Are the responses to opposite signs of MJO forcing mirror images? (nonlinearity)Which response is less sensitive to initial condition and background flow? with less spread?How does the response depend on extratropical jet initial condition? Questions:

  • 3 sets of experiments: 1) Control 2) +MJO forcing 3) MJO forcingFrom 360 different initial conditions30-day nonlinear integrations

    Nonlinearity

  • Thermal forcingExp1 forcingExp2 forcingLin et al. (2010)+MJO thermal forcing

  • NonlinearityZ500 response

  • spread+MJO response has less spread, less sensitive to initial condition

  • EOFDownstream shiftIntensifyof 360 Z500 day 6-10 responses to the same +MJO

  • Dependence on initial condition U200Jet intensifiesJet moves southward

  • Summary

    There is significant nonlinearity in response in mean response and spreadResponse to MJO is more sensitive to initial condition (when the heating is over central Pacific)Response sensitive to the strength and position of East Asian jetImplication to subseasonal forecasting: MJO phase and jet initial condition

  • *To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO****To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO**To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO*To assess the contribution of moisture and convections to LFV, especially the MJO.Does tropical intraseasonal variability (TIV) exist in a dry model? Global view of the intraseasonal variability.Implication to the MJO