El Niño and La Niña Heather Price Science Seminar January 7, 2011 SNL

1. El Niño and La Niña Heather Price Science Seminar January 7, 2011 SNL

2. “Australia blames 'La Niña' for epic floods” (Sydney, Jan 6, 2011) “Who's to blame for lack of snow? La Niña or Boulder City Council?” (Boulder , Colorado, Jan 6, 2011) “Tough little girl. La Niña proves as disruptive as her better-known brother” (The Economist, Jan 6, 2011) “La Niña Snows Make Skiers Smile” (Mt. Bachelor, Oregon , Jan 3, 2010)

4. Asia South America Normal Conditions upwelling • Strong winds from east to west over Pacific • Water piled up in western Pacific (~1/2 meter) • SST sea surface temperature in west (red=30C) and • cold in east (blue=22C) • Rainy over SE Asia, dry over S. America. • Upwelling off South American coast • Good anchovy fishing off Peru

5. La Niña Conditions • Stronger winds from east to west over Pacific • Water piled up in western Pacific (>1/2 meter) • SST sea surface temperature in west (red=30C) and cold in east (blue=22C) • Rainy over SE Asia, Australia dry over S. America. • Good anchovy fishing off Peru, from increased upwelling • North America (US) Forecasts • Heavier precipitation in Pacific Northwest, Northern Rockies, Great Lakes, Ohio valley • Below average precipitation in Southwest and south east states • Upwelling off South American coast

6. El Niño Conditions No upwelling • Weak or even reversed winds from east to west over Pacific • Water no longer piled up in western Pacific • Warm water pool in west (30C) moves east • Rainy over central Pacific, flooding in Peru • Upwelling off South American weakens or stops • Really poor or no anchovy fishing off S. America, Peru • Positive feedback loop helps El Nino grow: • weaker winds warmer ocean weaker winds

7. Sea Level and Sea Surface Temperature (SST) http://www.cdc.noaa.gov/~jjb/anim.html

8. El Nino La Nina

10. La Niño El Niño

11. El Niño La Niña impacts ocean productivity Normal Conditions and La Nina = more productive Nutrients El Nino Conditions = less productive

12. How does El Niño impact weather? Normal/La Nina El Nino • Jet stream (~12km) shifts North • during El Nino years (thin arrows) • A ridge of high pressure over North America's west coast during El Nino winters steers storms that would otherwise pass through Washington and Oregon northward toward the coast of Alaska as indicated by the big red arrow. • More storms develop in the Gulf of Mexico, bringing heavy rains to much of the southern United States during El Nino. • Strengthening of the westerlies in the Southern Hemisphere during its winter season brings heavy precipitation to parts of southern Brazil and northern Chile and Argentina.

13. Typical January to March Weather Anomalies El Nino La Nina

14. Fires in the Amazon El Niño plays havoc with world weather Worsening drought in Sahel • Weakens Indian Monsoon. • Pushes mid-latitude storms poleward. • Causes drought in central North America.

15. 1983 El Niño caused severe drought, heat waves and Bushfires in Australia. Flames devour farmland in Victoria, Australia. El Niño triggered prolonged drought of 1983 made fire a constant hazard. In 1983, winds whipped fires from Adelaide to Melbourne, destroying seven towns and several thousand homes.

16. Apparently La Niño also plays havoc with world weather “Australia blames 'La Niña' for epic floods” (Sydney, Jan 6, 2011) “Who's to blame for lack of snow? La Niña or Boulder City Council?” (Boulder , Colorado, Jan 6, 2011) “Tough little girl. La Niña proves as disruptive as her better-known brother” (The Economist, Jan 6, 2011) “La Niña Snows Make Skiers Smile” (Mt. Bachelor, Oregon , Jan 3, 2010)

17. SST = Sea Surface Temperature

18. What’s happening with now Sea Surface Temperature (SST)? http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.html

20. El Niño Observing System used to predict and monitor • Long term operational support for Pacific Ocean observations that are the foundation of accurate El Nino forecasts: • Moored buoysDrifting buoysVolunteer ship temperature probesSea level measurements • Total cost of these ocean observations is $4.9 million per year

21. November 4, 2010 ENSO Alert System Status:La Niña is expected to last at least into the Northern Hemisphere spring 2011. Consistent with nearly all ENSO forecast models, La Niña is expected to last at least into the Northern Hemisphere spring 2011. A large majority of models also predict La Niña to become a strong episode (defined by a 3-month average Niño-3.4 index of –1.5oC or colder) by the November-January season before gradually weakening. A few of the models, including the NCEP Climate Forecast System (CFS), suggest that La Niña could persist into the Northern Hemisphere summer 2011. However, no particular outcome is favored beyond the Northern Hemisphere spring due to large model disagreement and lower model skill during the period. Likely La Niña impacts during November 2010-January 2011 include suppressed convection over the central tropical Pacific Ocean, and enhanced convection over Indonesia. Expected impacts in the United States include an enhanced chance of above-average precipitation in the Pacific Northwest, Northern Rockies (along with a concomitant increase in snowfall), and Ohio Valley, while below-average precipitation is most likely across the south-central and southeastern states. Climate Prediction Center web page: http://www.cpc.ncep.noaa.gov

25. In recent years El Niño events have occurred more frequently as the global temperature anomalies associated with each El Niño increase. • Extreme regional weather and climate anomalies associated with El Niño are being exacerbated by increasingly higher temperatures. • The warmer conditions are linked to higher concentrations of atmospheric greenhouse gases. National Climatic Data Center, Asheville, NC

26. Bleached Coral El Niño impacts on Coral Reefs Healthy Coral During El Nino years ocean temperatures rise causing coral bleaching. • Coral Bleaching • Occurs when coral polyps expel their colorful symbiotic zooxantheallae algae. • Warmer ocean temperatures just 2 degree C above average cause bleaching. • The algae photosynthesize organics for the coral polyps while the polyps provide nutrients for the algae. • Coral polyps die within weeks if the algae does not return.

27. Healthy Coral What’s so special about Coral Reefs? • Coral reefs are Rainforests of the Ocean • Reefs cover only 0.2% of ocean’s area but are: • some of the Earth’s most diverse living ecosystems; • habitat for 1/3 of marine fish and tens of thousands of other species (turtles, eel, marine mammals, etc); • nurseries for non-reef dwelling species; • support local economies, fisheries and tourism; • protect shorelines and coastal communities from • storms, wave damage and erosion; • generate beach sand; • Full of new and undiscovered biomedical resources that we've only just begun to explore.

28. Coral Bleaching past 15 years Source: ReefBase 2008 "It's a scary picture from what we've seen. Over the last 15 years, the Northern Hemisphere tropical temperatures have gone up by ½ degree Fahrenheit.” “The problem is if we have another few episodes (of bleaching) like we did a few years ago, when the temperatures get too high for too long, we're limited to what we can do.“ Alan Strong of NOAA

29. Coral Reefs provide valuable clues • record of El Nino events for past 130,000 yrs • most intense El Nino events occurred in past 100 yrs • two strongest El Nino were 1982 & 1997 • bleaching is considered “canary in coal mine” for • climate change How do we study Corals? Corals record changes in local rainfall and temperature in the ratio of two isotopes of oxygen incorporated in their calcium carbonate skeletons. Cores are drilled through boulder-size corals and successive thin slices reveal the change in oxygen composition - and climate - back in time.