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Mike Groenke (Atmospheric Sciences Major)

MICHAEL A. ALEXANDER , ILEANA BLADE, MATTHEW NEWMAN, JOHN R. LANZANTE AND NGAR-CHEUNG LAU, JAMES D. SCOTT. The Atmospheric Bridge: The Influence of ENSO Teleconnections on Air–Sea Interaction over the Global Oceans. Mike Groenke (Atmospheric Sciences Major).

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Mike Groenke (Atmospheric Sciences Major)

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  1. MICHAEL A. ALEXANDER, ILEANA BLADE, MATTHEW NEWMAN, JOHN R. LANZANTE AND NGAR-CHEUNG LAU, JAMES D. SCOTT The Atmospheric Bridge: The Influence of ENSO Teleconnections on Air–Sea Interaction over the Global Oceans Mike Groenke (Atmospheric Sciences Major)

  2. El Nino-Southern Oscillation (ENSO) • Tropical Pacific region • Associated sea surface temperature (SST) anomalies • Warm=El Nino…Cold=La Nina • ENSO events drive ocean SST anomalies around globe • “Atmospheric bridge” because connects the world’s oceans

  3. Better explanation • http://www.youtube.com/watch?v=IvmeUStFvz8

  4. Q-net: net surface heat flux • We=entrainment heat flux • Vek=Ekman transport

  5. Wait, why do we care? • Essential for prediction of SSTs in tropical Atlantic • Contributes to leading patterns of SSTs on many times scales around globe • Tests ability to simulate global atmospheric response to ENSO • Separate between atmospheric forcing and ocean feedbacks • Influence on marine ecosystems

  6. ENSO Really Matters

  7. Questions that remain • Ocean-atmosphere interactions via changes in solar radiation, precipitation, and boundary layer processes. • Indian Ocean response to ENSO • Feedback from SST anomalies beyond equatorial East Pacific

  8. Purpose of this study • Review of how well we understand the “atmospheric bridge” • Present new data/observations • Focus on Pacific North America (PNA) region

  9. Modeling Used • 3 major models were used • “Control model” • “MLM” or mixed layer model • “NP-MLM” or North Pacific mixed layer model • NCEP-NCAR re-analysis project data also used

  10. Methods • Look at observations from past • Interpret data and form hypotheses and assumptions • Run models and look for reproduction of observed data • Interpret results

  11. Main Focus • Global precipitation influences from ENSO • Related SST anomalies on different times scales around the globe • Relationship between SST and SLP

  12. Effects On Global Precip • Changes in jet stream speeds from ENSO • Anomalous clockwise flow=higher precip

  13. ENSO Felt Around the World SST Anomalies • North Pacific • Opposite sign of ENSO • Pacific Decadal Oscillation influenced by tropical and extra-tropical forcing • Far north near “sub arctic front” not correlated

  14. Current Example

  15. ENSO Felt Around the World • Tropical Atlantic: • Warm waters just north of equatorial Atlantic found with El Nino in spring after ENSO peak • Southern Atlantic only weak links plus 3-6 months lag time • Indian Ocean • Warms with El Nino • Lag time of 3-6 months, but earlier than Atlantic • Often during summer/fall also

  16. Relationship in SLP & SST’s • Stronger Aleutian low (by 9mb) during Nino vs. Nina • Causes increased westerlies in north Pacific • Advects cold air into northern waters and warm air along west coast of North America • Consistent with previous SST map • Model differences likely due to error and missing ocean dynamics Figure on next slide!!

  17. Check out the pressure! Observed MLM Simulation

  18. Shaded areas indicated a 95% statistical significance in difference between taking local coupling effects into account or not

  19. Other ENSO Induced Effects • MLD (Mixed Layer Depth) • The depth at which the temperature is 1 degree C cooler than the surface • Salinity • Reemergence of SST anomalies • Fades during summer, but effects next winter

  20. Summary • Atmospheric response to changes in SST’s due to ENSO influences conditions across the rest of the globe • This connection is called the “Atmospheric Bridge” • Clear link in ENSO SST anomalies and other anomalies in Northern Pacific, north tropical Atlantic, and Indian Oceans • Atmospheric response affects SLP and jet stream patterns across the globe including deep trough near Alaska

  21. Summary (cont’d) • Other impacts include effects on MLD, salinity, and the reemergence of anomalies during the following year • Changes in net heat flux are the leading driver of SST anomalies in the ENSO region • Ocean-air coupling modifies effects on pressure fields in the North Pacific

  22. My Thoughts • Good review of impacts from El Nino/La Nina events • Too many assumptions that reader knows extremely technical processes • Further research in this field could improve seasonal forecasting • Lacked significant mention of effects from climate change

  23. Questions?

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