How long does ENSO last? El Niño typically lasts 9–12 months, and La Niña typically lasts 1–3 years. Both tend to develop during March–June, reach peak intensity during December–April, and then weaken during May–July. However, prolonged El Niño episodes have lasted 2 years, and even as long as 3-4 years.
What is the time scale of the El Niño-Southern Oscillation?
The net result is that the tropical Pacific combined ocean/atmosphere system naturally oscillates with a characteristic timescale of roughly 2-7 years. During the El Niño phase of the oscillation, the eastern/central tropical Pacific is warmer than usual.
What is El Nino Southern Oscillation quizlet?
-El Niño-Southern Oscillation (ENSO) is an irregularly periodical variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting much of the tropics and subtropics. -El Niño is accompanied with high, and La Niña with low air surface pressure in the tropical western Pacific.
Does El Niño cause Southern Oscillation?
El Niño and the Southern Oscillation, also known as ENSO is a periodic fluctuation in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean.
What happens during El Nino Southern Oscillation quizlet?
El Nino Southern Oscillation, trade winds weaken & warm surface water moves toward South America. Diminished fisheries off South America, drought in western Pacific, increased precipitation in southwestern North America, fewer Atlantic hurricanes.
What exactly does the oscillation in Southern Oscillation refer to?
Southern Oscillation, in oceanography and climatology, a coherent interannual fluctuation of atmospheric pressure over the tropical Indo-Pacific region. The Southern Oscillation is the atmospheric component of a single large-scale coupled interaction called the El Niño/Southern Oscillation (ENSO).
What causes Southern Oscillation?
These motions – rising in the west, sinking in the east – are connected through easterly trade winds near the surface and a westerly wind aloft, forming the Walker Circulation. Fluctuations in the position and intensity of the Walker Circulation cause the Southern Oscillation.
What happens during El Nino Southern Oscillation?
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.
What is the difference between the El Nino and La Nina?
El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific. It represents the warm phase of the ENSO cycle. La Niña refers to the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific.
How can El Nino La Niña Southern Oscillation affect weather quizlet?
-High pressure and sinking air dominates the coastal region of South America, which produces clear, fair, and dry weather. -On the other side of the pacific, a low-pressure region and rising air creates cloudy conditions and lots of rain in Indonesia, New Guinea and Northern Australia.
Is La Niña year 2020?
The La Niña climate pattern is forecast to return this fall and last through the winter of 2021-22, federal forecasters reported Thursday. The prediction center said this year’s La Niña (translated from Spanish as “little girl”) is likely to persist through the winter.
What are 2 effects of El Niño?
Severe drought and associated food insecurity, flooding, rains, and temperature rises due to El Niño are causing a wide range of health problems, including disease outbreaks, malnutrition, heat stress and respiratory diseases.
Is La Niña wet or dry?
“Typically speaking, La Niñas turn out dry for Southern California, and El Niños turn out wet. But not always,” Patzert said. La Niña is the cool phase of a climate phenomenon called the El Niño-Southern Oscillation, often referred to as ENSO.
What is an El Nino effect?
El Nino is a climate pattern that describes the unusual warming of surface waters in the eastern Pacific Ocean. El Niño has an impact on ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather from Australia to South America and beyond.
What happens during La Niña?
During La Niña events, trade winds are even stronger than usual, pushing more warm water toward Asia. Off the west coast of the Americas, upwelling increases, bringing cold, nutrient-rich water to the surface. These cold waters in the Pacific push the jet stream northward.
What causes La Niña?
La Niña is caused by a build-up of cooler-than-normal waters in the tropical Pacific, the area of the Pacific Ocean between the Tropic of Cancer and the Tropic of Capricorn. Unusually strong, eastward-moving trade winds and ocean currents bring this cold water to the surface, a process known as upwelling.
What happens to the surface pressure at opposite ends of the Pacific Ocean during the southern oscillation?
What happens to the surface pressure at opposite ends of the Pacific Ocean during the southern oscillation? This constituent swings in surface air pressure between the tropical eastern ocean waters and the western Pacific Ocean waters.
Who discovered the Southern Oscillation?
Two giants of 20th-century meteorology, Gilbert Walker and Jacob Bjerknes, are usually given credit for discovering the El Niño-Southern Oscillation phenomenon.
What does the Southern Oscillation Index measure?
The Southern Oscillation Index or SOI represents the difference in average air pressure measured at Tahiti and Darwin, Australia. More specifically, the SOI is calculated as the difference in monthly averages of standardized mean sea level pressure at each station.
Where does El Niño occur?
The Short Answer: El Niño is a weather pattern that occurs in the Pacific Ocean. During this time, unusual winds cause warm surface water from the equator to move east, toward Central and South America.
Is 2020 an El Nino or La Niña year?
But forecasters at NOAA’s Climate Prediction Center have issued a La Niña Watch, which means they see La Niña likely emerging (~55%) during the September-November period and lasting through winter. June 2021 sea surface temperature departure from the 1991-2020 average. Image from Data Snapshots on Climate.gov.
Does El Nino cause more hurricanes?
In general, warm El Niño events are characterized by more tropical storms and hurricanes in the eastern Pacific and a decrease in the Atlantic, Gulf of Mexico and the Caribbean Sea. The increased wind shear helps to prevent tropical disturbances from developing into hurricanes.
When was the last La Niña?
Recent years when La Niña Modoki events occurred include 1973–1974, 1975–1976, 1983–1984, 1988–1989, 1998–1999, 2000–2001, 2008–2009, 2010–2011, and 2016–2017. The recent discovery of ENSO Modoki has some scientists believing it to be linked to global warming. However, comprehensive satellite data go back only to 1979.