Where is the EQSOI?
How to stretch a graph in either direction?
What's the Southern Oscillation Index?
The Southern Oscillation Index (SOI) tracks the atmospheric part of the El Niño–La Niña climate pattern by comparing surface air pressure anomalies at Darwin, Australia, to pressure anomalies at Tahiti. The anomalies—departures from average conditions—indicate the strength of the Walker Circulation.
What is the Southern Oscillation Index and how is it measured?
The Southern Oscillation Index, or SOI, gives an indication of the development and intensity of El Niño or La Niña events in the Pacific Ocean. The SOI is calculated using the pressure differences between Tahiti and Darwin. Sustained negative values of the SOI below −7 often indicate El Niño episodes.
What is Southern Oscillation in simple terms?
Definition of Southern Oscillation climatology. : a periodic seesaw fluctuation in sea-level atmospheric pressures over the southern Pacific and Indian oceans that is believed to be linked to El Niño and La Niña events — compare arctic oscillation, north atlantic oscillation.
What is the difference between El Niño and Southern Oscillation?
El Niño and La Niña are the extreme phases of the ENSO cycle; between these two phases is a third phase called ENSO-neutral. El Niño: A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean.
Why is it called Southern Oscillation?
Unaware of any connection to El Niño, he discovered that atmospheric pressure fluctuated over the tropical Indo-Pacific region, which he termed the Southern Oscillation.
What does a negative Southern Oscillation Index mean?
The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. Prolonged periods of negative (positive) SOI values coincide with abnormally warm (cold) ocean waters across the eastern tropical Pacific typical of El Niño (La Niña) episodes.
Why is El Nino called 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.
Are we in La Niña or El Nino?
Based on all the available data, an official La Nina watch is still in effect, released by the NOAA's Climate Prediction Center: “La Niña is likely to continue into the Northern Hemisphere spring (77% chance during March-May 2022) and then transition to ENSO-neutral (56% chance during May-July 2022).
How does Southern Oscillation affect the climate of India?
As those conditions change, with the monsoon being linked to El Nino-Southern Oscillation phenomena, summer temperatures over much of India may rise to as high as 45 degrees Celsius, while the Indian Ocean is much cooler.
Is El Niño or La Niña worse?
Overall, El Niño contributes to more eastern and central Pacific hurricanes and fewer Atlantic hurricanes while, conversely, La Niña contributes to fewer eastern and central Pacific hurricanes and more Atlantic hurricanes..
How is El Niño connected to Southern Oscillation?
The Southern Oscillation is a change in air pressure over the tropical Pacific Ocean. When coastal waters become warmer in the eastern tropical Pacific (El Niño), the atmospheric pressure above the ocean decreases. Climatologists define these linked phenomena as El Niño-Southern Oscillation (ENSO).
What is meant by Southern Oscillation state an important feature of it?
Southern oscillation refers to shifting the surface air pressure between the tropical eastern Pacific and eastern Indian oceans. An important feature connected with the Southern Oscillation (SO) is the El Nino.
Southern Oscillation Index (SOI) data
File format (SOI with 3 decimal places) for year = 1866 to endyear format(i5,12f8.3,f8.3) year, 12 * monthly value, annual value NOTE THIS FORMAT WAS CHANGED ON 21 JULY 2017
ENSO Indices - National Weather Service
ENSO Indices . Southern Oscillation Index (SOI) standardized anomaly of the mean sea level pressure difference between Tahiti and Darwin. traditional ENSO index
Southern Oscillation Index (SOI) history
Use buttons to zoom time or, in graph area, hold Shift key, click and drag. in graph area, pinch in or out to zoom, drag to pan ...
Southern Oscillation Index | Earth science | Britannica
Other articles where Southern Oscillation Index is discussed: Australia: Climate: Monitoring the Southern Oscillation Index (SOI) is now considered essential to seasonal weather forecasting. The SOI is strongly negative when weak Pacific winds bring less moisture than usual to Australia. Prolonged negative phases are related to El Niño episodes in the South Pacific, and most of Australia’s…
What is the Southern Oscillation Index?
The Southern Oscillation Index (SOI) is one measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e. , the state of the Southern Oscillation) during El Niño and La Niña episodes.
How long is the ENSO cycle?
The time series of the SOI and sea surface temperatures in the eastern equatorial Pacific indicates that the ENSO cycle has an average period of about four years, although in the historical record the period has varied between two and seven years.
Southern Oscillation Index
This figure displays a time series, in the form of vertical color bars, of the monthly standardized Southern Oscillation Index (SOI) from January 1951 to present.
Dataset Documentation
Standardized difference of standardized Tahiti minus standardized Darwin sea level pressure anomalies
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Download Climate Timeseries
Note: file updated Feb 14 2017. Some old values were corrected. See the CRU webiste for more information.
Southern Oscillation Index (SOI)
The SOI is defined as the normalized pressure difference between Tahiti and Darwin. There are several slight variations in the SOI values calculated at various centres. Here we supply the SOI (from CRU) which is based on the method given by Ropelewski and Jones (1987).
What Is ENSO
El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific—the El Niño-Southern Oscillation, or “ENSO” for short. The pattern shifts back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation.
U.S. Impacts
El Niño is anchored in the tropical Pacific, but it affects climate "downstream" in the United States. In the summer, El Niño's primary influence on U.S. climate is on the hurricane season in both the eastern Pacific and the Atlantic. In winter, it influences the jet stream and the path of storms that move from the Pacific over the United States.
Global Impacts
El Niño and La Niña have their strongest influence on global climate during the Northern Hemisphere winter. During La Niña winters, the southern tier of the United States is often drier than normal. Northern Australia, Indonesia, and the Philippines are often wetter than normal.
Understanding the ENSO Alert System
On the second Thursday of each month, scientists with NOAA’s Climate Prediction Center in collaboration with forecasters at the International Research Institute for Climate and Society (IRI) release an official update on the status of the El Niño-Southern Oscillation (ENSO). Here is a description of the categories and criteria they use.
Where is the EQSOI?
The EQSOI is calculated as the difference in standardized mean sea level pressure over a swath of the eastern equatorial Pacific Ocean (5°N-5°S, 80°W-130°W, labeled EPAC above) and another swath that spans Indonesia (5°N-5°S, 90°E-140°E, labeled INDO).
How to stretch a graph in either direction?
To squeeze or stretch the graph in either direction, hold your Shift key down, then click and drag. Additionally, a third index is used to characterize the phase of ENSO: the Equatorial Southern Oscillation Index or EQSOI represents the difference in air pressure measured over the eastern and western Pacific.