Will 2015 be a year of La Niña El Niño

or neither?

Heather Price March, 14 2015

Normal Conditions In the Pacific Ocean

•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

Asia

South America

upwelling

Normal Conditions

La Niña Conditions

• Higher pressure over Tahiti, lower pressure over Darwin• 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

• Lower pressure over Tahiti, higher pressure over Darwin• 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

No upwelling

El Niño Conditions

Normal Conditions

El Nino Conditions

SST = Sea Surface Temperature

http://www.cdc.noaa.gov/~jjb/anim.html

Sea Level and Sea Surface Temperature (SST)

El Nino Southern Oscillation Index:Low Pressure over Tahiti vs High over Darwin

•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

El Niño Observing System used to predict El Niño

• 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, including California.

•Strengthening of the westerly's in the Southern Hemisphere during its winter season brings heavy precipitation to parts of southern Brazil and northern Chile and Argentina.

Normal

El Nino

El Niño impacts weather

Typical January to March Weather Anomalies

El Nino

La Nina

What’s happening now?La Nina, El Nino, or Normal? Pacific Sea Surface Temperature

(SST)

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.html

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/gsstanim.shtml

Global Sea Surface Temperatures (SST)

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml#current

What can we expect in 2015 La Nina, Normal, or El Nino??

NOAA Model Precipitation for October to December 2015

EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION

14 May 2015  

ENSO Alert System Status: El Niño Advisory

Synopsis: There is an approximately 90% chance that El Niño will continue through Northern Hemisphere summer 2015, and a greater than 80% chance it will last through 2015.

By early May 2015, weak to moderate El Niño conditions were reflected by above-average sea surface temperatures (SST) across the equatorial Pacific, and by the corroborating tropical atmospheric response. The latest weekly Niño indices were +1.2oC in the Niño-4 region, +1.0oC in the Niño-3.4 region, and +1.2oC and +2.3oC in the Niño-3 and Niño-1+2 regions, respectively. Subsurface temperature anomalies remained substantially above average, partly in response to a downwelling oceanic Kelvin wave, which resulted in strong positive subsurface anomalies across the central and eastern Pacific. This anomalous warmth has subsequently persisted in association with El Niño-related ocean-atmosphere coupling. This coupling includes enhanced convection over the central equatorial Pacific, along with persistent low-level westerly wind anomalies over the western and central equatorial Pacific and persistent upper-level easterly wind anomalies over the central Pacific. Also, the equatorial Southern Oscillation Index (EQSOI) remained negative during the month. Collectively, these features reflect weak to moderate strength El Niño conditions.And Cliff Mass says so!

http://cliffmass.blogspot.com/2015/04/is-strong-el-nino-finally-coming.html

                                                           

Nutrients

Normal Conditions and La Nina = more productive

El Nino Conditions = less productive

El Niño La Niña impacts ocean productivity

• Weakens Indian Monsoon. • Pushes mid-latitude storms poleward. • Causes drought in central North America.

El Niño wreaks havoc on world weather

Fires in the Amazon

Worsening drought in Sahel

1983 El Niño causedsevere 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.

http://www.cpc.ncep.noaa.gov/

http://www.cpc.ncep.noaa.gov/

               

• In recent years El Niño events have occurred more frequently as the global temperature anomalies associated with each El Niño increase in intensity.

• 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

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.

El Niño impacts on Coral Reefs

During El Nino years ocean temperatures rise causing coral bleaching.

Bleached Coral

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.

Healthy Coral

Coral Bleaching past 15 years

"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

Source: ReefBase 2008

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.

El Niño / La Niña is Predictable

•Potential for billions of dollars in benefits to the US economy in:

AgricultureEnergy generationWater resourcesForestry

•Computer models show skill in forecasting tropical Pacific Ocean temperatures one to two years in advance

•El Nino forecasts improve the accuracy of seasonal and longer forecasts over the US

FisheriesTransportationCommercePublic health

Pacific Decadal Oscillation (PDO)

Warm Phase Cool Phase

SST

http://tao.atmos.washington.edu/pdo/

Warm Phase

Enhanced coastal ocean biological productivity in Alaska and inhibited productivity off the west coast of the contiguous United States

Dominated from:

• 1925-1946

• 1977 through (at least) the mid-1990's.

http://tao.atmos.washington.edu/pdo/

Cool Phase

Inhibited coastal ocean biological productivity in Alaska and enhanced productivity off the west coast of the contiguous United States (opposite warm phase)

Dominated from:

• 1890-1924

• 1947-1976

http://tao.atmos.washington.edu/pdo/