3 “normal” or “neutral” Equatorial trade winds blow westward Water “piles up” in western Pacific OceanWater is warmer in western Pacific OceanUpwelling of colder water in eastern Pacific OceanNormal precip patterns
6 What is the jet stream? Current of air flowing 150 to 300 mph High in troposphere (about 10 km)Over the boundary between 2 air masses.Usually blows from west to east.Aircraft can use or avoid a jet stream.
9 What causes the jet stream? The temperature difference between 2 air masses.The greater the temp. diff., the faster the jet stream.Seasons (temp. diff.) can cause jet stream to shift position. Also the ENSO.
12 El Nino Tradewinds slow and/or stop Warm water covers more of equator No upwelling in eastern Pacific Ocean (collapse of fishing industry in Peru)Global change in weather patterns
23 How to forecast the ENSO cycle? Need info about SST, ocean temperatures at depth and winds.
24 Array of TAO/TRITON Approx 70 moorings w/ about 400 buoys Completed Dec 1994 after 10 years17 ships on 83 cruises from 6 countries (multi-national)In Oct 1999, Japan assumed responsibility for western Pacific moorings (TRITON)
25 TAO/TRITON Tropical Atmosphere & Ocean Motivated by El Nino event
34 Put the TAO/TRITON data into a computer model Now can forecast path of storm track
35 Note that the location of the jetstream is influenced by the location of the convection, e.g. the main mean jetstream for La Niña starts to the left of the normal scenario. These are the teleconnections to our mid-latitude weather.
36 Benefits of accurate ENSO forecasts (hopefully, with predictions up to one year)
37 Drought forecasts Preparation for wildfires Cultivation of drought-tolerant cropsPlan food distribution in developing countries
38 Forecast of Excessive Precipitation Preparation for extremes: hurricanes, tornadoes, etcPreparation for local flooding: mudslidesMosquito control in malarial zonesPlanting of wet-tolerant crops
39 Forecast of change in ocean temperatures Predict profitable fishery sitesMonitor health of coral reef ecosystems
40 Economic benefits from forecasts Adjust the production of weather-related goods: vehicles, clothing, shelterAdapt use of recreational facilities: skiing, snowboarding, boatingPrepare for fluctuations in consumption of home-heating fuels
42 ENSO The El Nino-Southern Oscillation Cycle During normal years, equatorial trades blow westOcean is 0.5 m higher & warmer in western PacificUpwelling currents in eastern Pacific20 – 30 cm annual precip in San Diego(8 to 12 inches)
51 Note that the location of the jetstream is influenced by the location of the convection, e.g. the main mean jetstream for La Niña starts to the left of the normal scenario. These are the teleconnections to our mid-latitude weather.
52 For more info about ENSO search NOAAFor more info about ENSO
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