In a normal year....
Trade winds blow towards the equator and the warmer water of the western pacific.
The trade winds patterns are disrupted
Here the warmer water heats the air above causing convectional uplift, creatng low pressure weather conditions and rainfall over south east asia
In the East Pacific off the coast of Peru, the conditions are dry as the air returns and sinks here, creating the walker loop.
The trade winds either die or blow in the opposite direction
The pressure of the trade winds results in sea levels in Australasia being 50cm higher than in peru and sea temps 8C higher
The air movement also enables the winds to pull up water along the east coast of south america
the air circulation loop is reversed
On the east coast of south america there is a shallow warm upper layer overlying the deep cold layer of the ocean the boundary between these layers is the thermocline
The thermocline causes an upwelling of cold water bringing nutrients from the ocean bottom and producing optimum fishing conditions off the coast of peru
Facts about el nino
Trade winds in the western pacific die or blow in the opposite direction
it's like an exxagerated normal year
the water that is normally piled up in the west moves back to the east so that the sea level on the peruvian coast rises 30m and conditions are calmer across the whole pacific ocean.
The air circulation loop is reversed so that air sinks in the western pacific bringing drought to countries in that region
extremely strong trade winds
Air rises in the eastern pacific causing convectional rainfall- sometimes flooding in coastal areas in south america
The change in location of air distorts the jet streams causing world wide teleconnections
facts about la nina
An exaggerated normal year with a very strong walker loop
There are extremely strong trade winds pushing warmer water westwards and raising the sea level by up to a meter higher in indonesia and the phillipines
causes landslides in south america
Deep low pressure develops over south east asia causing heavy rain on account of the pacific there is a strong upwelling of cold water off the coast of peru
The higher than average pressure that occurs heer causes severe drought in the semi-arid areas of peru and northern chile
heavy rainfall in europe and flooding
The see sawing of atmospheric pressure between the easterm pacific and the indo australian area is called the southern oscillation
The effects of el nino on the west and east.
Drought in indonesia, australia and malaysia - west
many people die of extreme heat caused =east
mild winters in n.usa and w.canada -west
demise of pevurian fish catches - east
reduced hurricane season -west
increased rain in southern usa states
Increased galapago iguana mortality rate -west
lots of hurricanes in n america - west
heavy rainfall in europe in the spring causing flooding-east
high rain in s america leading to landslides in the andes - east
