1. Teleconnections and the MJO: intraseasonal and interannual variability Steven Feldstein June 25, 2012 University of Hawaii

2. Climate Prediction Center The dominant Northern Hemisphere teleconnection patterns North Atlantic Oscillation Pacific/North American pattern

3. NORTH ATLANTIC OSCILLATION University of Hamburg

4. Earliest NAO observations Norse (Viking) settlers arrived in Greenland in CE 985. The Norse, who appeared to be very interested observers of the weather, also seemed to be aware of teleconnection patterns in the North Atlantic basin. There was an anonymous Norwegian book (approx. CE 1230), entitled the `King's Mirror'. This book, in the form of a discussion between father and son, wrote that severe weather in Greenland coincides with warmer weather at distant locations, and vice versa.

5. Danish missionary Hans Egede (1745) wrote: “In Greenland, all winters are severe, yet they are not alike. The Danes have noticed that when the winter in Denmark was severe, as we perceive it, the winter in Greenland in its manner was mild, and conversely.” Hans Egede map in “History of Greenland” Walker (1932) used correlation analysis to find the dominant teleconnection patterns, including the NAO.

6. SEASONAL ROTATED EOFS DAILY ROTATED EOFS seasonal NAO daily NAO seasonal PNA daily PNA Feldstein (2000) Corr=0.98Corr=0.97

7. NAOPNA Period (years) Power Period (years) Power POWER SPECTRA An AR(1) process Power spectral density function Feldstein (2000)  = 9.5 days  = 7.7 days

8. DAILY NAO INDEX & FORECAST (since ~2002) Climate Prediction Center

9. Implication for interannual variability? Feldstein (2002)

10. Climate Noise: relationship between daily & interannual NAO variability Feldstein (2002) Most interannual NAO variability is from Climate Noise

11. Physical processes of the NAO Projections Streamfunction tendency equation NAO Feldstein (2003)

12. NAO AMPLITUDE Nonlinear Linear High-frequency eddies Low-frequency eddies Divergence Vorticity Advection LinearNonlinear + NAO DRIVING MECHANISMS Feldstein (2003)

13. Benedict et al. (2004) Day 1 Day 4 Day 7 Day 10

14. MODEL SIMULATION NAO -NAO + Franzke et al. (2004) Initial perturbation Area of small potential vorticity gradient

15. Physical processes for the PNA  In contrast to the NAO, the PNA is dominated by linear processes: stationary eddy advection. Both phases of the PNA are excited by tropical convection  Tropical convection excites a small amplitude Rossby wave train via linear dispersion  Synoptic-scale eddies (remote pos phase; local neg phase) amplify PNA

16. OLR anomalies associated with the PNA

17. 300-hPa streamfunction anomalies associated with OLR

18. PA PNA PNA Life Cycle

19. Summary of Physical Processes Prominent Northern Hemisphere teleconnection patterns have a timescale of 7-10 days Interannual variability of most teleconnection patterns arises primarily from climate noise The NAO is comprised of the remnants of breaking synoptic-scale waves; nonlinear process The PNA wavetrain is excited by tropical convection and then amplified by breaking synoptic-scale waves; primarily a linear process

20. Tropical Convection Associated with the Madden-Julian Oscillation (MJO) Phase 1 Phase 2 Phase 3 Phase 4 Phase 5 Phase 6 Phase 7 Phase 8 Time between Phases ~ 6 days 180۫° 60۫°W 20۫°E Dominant intraseaonal oscillation in the tropics MJO cycle: 30-60 days Shading OLR Time between phases ~ 6 days From Wheeler and Hendon (2004)

21. Does the MJO affect Arctic surface air temperature? MJO Phase 1 (neg PNA)MJO Phase 5 (pos PNA)

22. Zonal-mean zonal wind and temperature MJO Phase 1 (neg PNA) MJO Phase 5 (pos PNA)

23. Eliassen-Palm Fluxes associated with the MJO MJO Phase 1 (Phase 5) associated with a reduced (increased) poleward heat and wave activity flux Planetary-scale (k-1,3) Synoptic-scale (k=4,8)

24. Summary of physical processes (projections onto 7-10 day SAT) MJO Phase 5 (pos PNA)MJO Phase 1 (neg PNA)

25. Mean Meridional Circulation Negative PNAPositive PNA

26. Multi-level primitive equation model calculation of MJO- induced Arctic SAT change (GFDL dynamical core)  Use MJO-like steady heating profiles for MJO phases 1 and 5 (100 randomly selected ensemble members): Initial value problem MJO phase 1 MJO phase 5

27. MJO-induced poleward tracer (H 2 0) transport Composite evolution of anomalous tracer concentration MJO phase 1MJO phase 5 Tracer (H 2 0) transported equatorward (poleward) during MJO phase 1 (phase 5) (Perhaps can explain observed downward IR associated with MJO)

28. Sensitivity of midlatitude response to initial conditions Projections onto 7-13 day SAT Response to MJO convection very sensitive to intial conditions MJO Phase 1 (neg PNA)MJO Phase 5 (pos PNA)

29. Concluding remarks Most of the major teleconnection patterns have a time scale of less than 10 days Most of the interannual variability of the major teleconnection patterns arises from climate noise The NAO and arises from synoptic-scale wave breaking and the PNA as a Rossby wave train response to MJO convection followed by amplification by synoptic-scale wave breaking MJO impacts Arctic SAT through changes in the excitation of poleward Rossby wave propagation (poleward heat flux and eddy-induced adiabatic warming/cooling) : Poleward Rossby wave propagation is weakened (strengthened) in MJO phase 1 (phase 5) and is associated with less (more) localized tropical convection Downward IR (surface sensible and latent heat flux) enhances (weakens) the impact of the MJO on Arctic SAT Anomalous downward IR may be associated with changes in poleward moisture transport associated with MJO