Understanding El Nino and La Nina

Understanding El Nino and Understanding El Nino and La Nina La Nina

Aim: To understand the what this Aim: To understand the what this weather phenomena is and what weather phenomena is and what

conditions it brings (A.K.A – To conditions it brings (A.K.A – To understand a bloody difficult part of understand a bloody difficult part of

atmospheric physics!!)atmospheric physics!!)

3 Steps to success 3 Steps to success 1.1. Define the terms La Nina and El Define the terms La Nina and El

Nino and be able to distinguish Nino and be able to distinguish between them bothbetween them both

2.2. To describe the phenomena with To describe the phenomena with reference to atmospheric dynamicsreference to atmospheric dynamics

3.3. To explain the impacts of the To explain the impacts of the phenomena phenomena

Aim: To understand the what this weather phenomena is Aim: To understand the what this weather phenomena is and what conditions it bringsand what conditions it brings

Brain Warm-UpBrain Warm-Up

• What are El Nino and La NinaWhat are El Nino and La Nina

• What types of conditions do they What types of conditions do they bring?bring?

• What are the impacts of this weather What are the impacts of this weather phenomena?phenomena?


Step 1 – La NinaStep 1 – La Nina• A cooling of the surface water of the eastern A cooling of the surface water of the eastern

and central Pacific Ocean, occurring and central Pacific Ocean, occurring somewhat less frequently than El Niño events somewhat less frequently than El Niño events but causing similar, generally opposite but causing similar, generally opposite disruptions to global weather patterns. La disruptions to global weather patterns. La Niña conditions occur when the Pacific trade Niña conditions occur when the Pacific trade winds blow more strongly than usual, pushing winds blow more strongly than usual, pushing the sun-warmed surface water farther west the sun-warmed surface water farther west and increasing the upwelling of cold water in and increasing the upwelling of cold water in the eastern regions. Together with the the eastern regions. Together with the atmospheric effects of the related atmospheric effects of the related southern southern oscillationoscillation, the cooler water brings drought , the cooler water brings drought to western South America and heavy rains to to western South America and heavy rains to eastern Australia and Indonesia. eastern Australia and Indonesia.


Step 1 – El NinoStep 1 – El Nino• A warming of the surface water of the eastern and A warming of the surface water of the eastern and

central Pacific Ocean, occurring every 4 to 12 years central Pacific Ocean, occurring every 4 to 12 years and causing unusual global weather patterns. An El and causing unusual global weather patterns. An El Niño is said to occur when the trade winds that Niño is said to occur when the trade winds that usually push warm surface water westward weaken, usually push warm surface water westward weaken, allowing the warm water to pool as far eastward as allowing the warm water to pool as far eastward as the western coast of South America. When this the western coast of South America. When this happens, the typical pattern of coastal upwelling happens, the typical pattern of coastal upwelling that carries nutrients from the cold depths to the that carries nutrients from the cold depths to the ocean surface is disrupted, and fish and plankton die ocean surface is disrupted, and fish and plankton die off in large numbers. El Niño warming is associated off in large numbers. El Niño warming is associated with the atmospheric phenomenon known as the with the atmospheric phenomenon known as the southern oscillationsouthern oscillation, and their combined effect , and their combined effect brings heavy rain to western South American and brings heavy rain to western South American and drought to eastern Australia and Indonesia. El Niño drought to eastern Australia and Indonesia. El Niño also affects the weather in the United States, but not also affects the weather in the United States, but not as predictably. as predictably.


El Nino – Typical surface ocean El Nino – Typical surface ocean circulationcirculation

El Niño El Niño conditionsconditions

• Normal Normal

• El Niño – strong El Niño – strong counter-currentcounter-current

El Niño El Niño conditionsconditions

• NormalNormal

• El nino – El nino – strong strong countercurrentcountercurrent

• http://esminfo.prenhall.com/science/http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNigeoanimations/animations/26_NinoNina.htmlna.html

http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html



Prediction of El NinoPrediction of El Nino• SatellitesSatellites

– provide data on tropical rainfall, wind, and provide data on tropical rainfall, wind, and ocean temperature patterns, as well as changes ocean temperature patterns, as well as changes in conditions for hurricane formation.in conditions for hurricane formation.

• Ocean buoys Ocean buoys – help to monitor sea-surface and upper ocean help to monitor sea-surface and upper ocean

temperatures.temperatures.

• Radiosondes Radiosondes – balloon-borne instrument platforms with radio balloon-borne instrument platforms with radio

transmitting capabilities, help to monitor global transmitting capabilities, help to monitor global weather and climate patternsweather and climate patterns

• Super computers Super computers – gather all of the weather data around the world gather all of the weather data around the world

and put it into useful formats used by scientists.and put it into useful formats used by scientists.– Run models for future changeRun models for future change

Understanding El Nino and La Nina

Documents

weather phenomena

ocean surface

weather data

warm surface water

warmed surface water

warm water

nia conditions

nio warming