What weather phenomena has the largest impact on our weather in Texas?

El Niño and La Niña

Definitions: El Niño - Unusually warm surface water temperatures in the Pacific ocean caused by weak or reversed direction trade winds. La Niña - Unusually cold surface water temperatures in the Pacific ocean caused by strong easterly trade winds.

Strange phenomenon occur during an El Niño and La Niña like...

Brush fires caused by drought in Texas (La Niña) From the decline of anchovy populations to the increase of drought and tropical storms. All of these phenomenon have been linked to El Niño and La Niña events.

Increased Tropical Storms (La Niña)

Hurricane Floyd was HUGE! (1999 - La Niña)

Causing devastating floods in Australia (2010-2011 La Niña)

Peruvian anchovy populations declined (El Niño) Cooler, nutrient rich waters associated with El Niño drop along with the thermocline, driving the anchovy population down with it, or killing off a large portion.

More tornadoes through tornado alley? NO!!! Scientists have found no significant correlation between El Niño and La Niña weather patterns and increased tornadoes.

Movement of Ocean Water Surface currents Deep ocean currents Upwelling

Surface Ocean Currents Currents that are controlled by the wind. ~¼ mile depth, 10%

Currents controlled by water density: temperature and salinity Deep Ocean Currents Currents controlled by water density: temperature and salinity 90% of the ocean water moves in deep ocean currents

Upwelling upwelling brings up cold, nutrient-rich waters to the surface, which encourage seaweed growth and support blooms of phytoplankton.

What causes the patterns? Normal

What causes an El Niño? Weak trade winds and weak upwelling cause warm water off the coast of S. America

What causes a La Niña? Strong trade winds blow surface water towards east, creating colder surface temperatures off South American coast.

Sea surface anomalies associated with El Niño

SST differences between El Niño and La Niña Under normal conditions, warm surface water is pushed away from the coasts of Peru by the trade winds. The relaxed trade winds associated with El Niño in the central and western Pacific leads to a depression of the thermocline (the buffer zone between the upper layer of water and the frigid ocean below) in the eastern Pacific, and an elevation of the thermocline in the west. During La Niña episodes, the equatorial sea surface temperatures (SST) are abnormally cold from the date line eastward to the west coast of South America, and tropical rainfall and convection tends to be focused over the western equatorial Pacific and Indonesia.

QUIZ! Which is which… Normal, El Niño, La Niña? B C

Were you’re predictions correct?

How can we predict an El Niño or La Niña event?

Need measurements to make predictions

NOAA drifting buoys Measures... temperature currents winds Observations of conditions in the tropical Pacific are considered essential for the prediction of short term (a few months to 1 year) climate variations. To provide necessary data, NOAA operates a network of buoys which measure temperature, currents and winds in the equatorial band. These buoys daily transmit data which are available to researchers and forecasters around the world in real time. But what about the rest of the ocean outside the equatorial band? Since oceans cover about 70% of the earth’s surface, our ships, buoys and other in situ (at the collection site) instruments can’t possible cover that much space. Thanks to advanced space technology, we can now use satellites to help us collect large amounts of ocean data.

Satellites Instruments on satellites measure wind, waves, temperature of the sea surface, ocean color, ocean surface currents, and tides. Satellites have revolutionized the ocean sciences. They have advanced our knowledge about the weather and ocean processes more than any other tool. Instruments on satellites measure wind, waves, temperature of the sea surface, ocean color, ocean surface currents, and tides. Oceanographers can use these satellite measurements for numerical modeling to predict what is happening in the deep ocean.

Where they monitor… The TOPEX/Poseidon (T/P) was launched in 1992 and has since mapped the ocean's surface topography. T/P covers the entire planet every 10 days--an impossibility for a ship. Radar altimeters on TOPEX/Poseidon (T/P) accurately measures the satellite's distance from the ocean's surface and tells us about the ocean's surface currents, winds, and wave heights. TOPEX/Poseidon data are used to predict the position of swift currents that appear to be connected with eddies. Eddies are spinning water currents--like a giant whirlpools and are considered to be the "weather of the oceans." Knowing the locations of eddies can increase the safety of workers on oil production platforms and other ocean going vessels. It is helpful in ship routing, commercial fishing, sailing, hurricane prediction, studying ocean circulation, and climate forecasting.

Videos http://www.youtube.com/watch?v=SR5VPAqVQBw    El Nino explanation video  3min   http://www.youtube.com/watch?v=jEAv-9TZktY   La Nina explanation video  3.5min http://www.youtube.com/watch?v=iWTucpsClLc  Austin newscast in January talking about Australia flooding  2min http://www.youtube.com/watch?v=l5x8dJ57xkk  Texas weatherman predictions for this year from July 2010.   about 3min http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html    All three animations