Data Library Maproom
Maproom ENSO Monitoring

El Niño, La Niña and the Southern Oscillation

"ENSO" refers to the El Niño/Southern Oscillation, the interaction between the atmosphere and ocean in the tropical Pacific that results in a somewhat periodic variation between between below-normal and above-normal sea surface temperatures and dry and wet conditions over the course of a few years.

This year-to-year or multi-year variability in oceanic and atmospheric conditions in the tropical Pacific has far-reaching impacts, called "teleconnections", on seasonal precipitation and temperature patterns in many areas of the globe. This Maproom includes maps and analyses useful for monitoring ENSO and its wide-ranging impact on climate.

Climate Impacts
Historical Probability of Seasonal Precipitation Tercile Conditioned on ENSO
This figure shows the historical probability (given as a percentage) of seasonal (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec) station precipitation totals falling within the upper (wet) one-third, middle (near-normal) one-third, or bottom (dry) one-third of the historical (1901-1990) distribution given the state of ENSO (ElNino, Neutral, LaNina) during that same season.
ENSO and All-India Rainfall
The quintessential ENSO-rainfall correlation is the connection between India rainfall and ENSO.
La Niña and Precipitation Terciles
For a given 3-month season of the calendar year (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec), this animated map indicates which precipitation tercile from the 1901-1990 distribution the median value of seasonal station precipitation in La Niña years would belong to. This is one way of showing how seasonal precipitation tends to increase or decrease in some locations during La Niña conditions.
El Niño and Precipitation Terciles
For a given 3-month season of the calendar year (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec), this animated map indicates which precipitation tercile from the 1901-1990 distribution the median value of seasonal station precipitation in El Niño years would belong to. This is one way of showing how seasonal precipitation tends to increase or decrease in some locations during El Niño conditions.
Bulletins
ENSO Update (IRI)
Monthly discussion of the current state of the El Niño-Southern Oscillation (ENSO) from the IRI.
El Niño Wrap-Up (BOM)
A regular commentary on the El Niño-Southern Oscillation, from the Australian Bureau of Meteorology (BOM).
Weekly Tropical Climate Note (BOM)
A weekly discussion of the state of the climate in the tropics, from the Australian Bureau of Meteorology (BOM).
ENSO Diagnostic Discussion (CPC)
A monthly analysis and summary of current ENSO conditions, from the Climate Prediction Center (CPC)
Longitude x Time
Equatorial Pacific/Indian Ocean Five-Day Running Average 925 hPa Zonal Wind Anomaly Hovmoller
This is a Hovmoller diagram (Longitude x Time) showing five-day running average zonal wind anomalies at 925 hPa averaged over 5°S to 5°N, for the past 120 days, across the equatorial Indian and Pacific Oceans.
Pentad Outgoing Longwave Radiation Anomaly
This is a Hovmoller diagram (Longitude x Time) showing five-day average outgoing longwave radiation (OLR) anomalies averaged over 5°S to 5°N, for the past year across the equatorial Pacific Ocean.
Monthly OLR and SST Anomaly
This is a Hovmoller diagram (Longitude x Time) showing monthly outgoing longwave radiation (OLR) anomalies and sea surface temperature (SST) anomalies averaged over 5°S to 5°N, for the past 36 months across the equatorial Pacific Ocean.
Monthly OLR and SST Climatology
This is a Hovmoller diagram (Longitude x Time) showing the outgoing longwave radiation (OLR) monthly climatology and sea surface temperature (SST) monthly climatology averaged over 5°S to 5°N across the equatorial Pacific Ocean.
Seasonal OLR and SST Anomaly
This is a Hovmoller diagram (Longitude x Time) showing seasonal (three-month average) outgoing longwave radiation (OLR) anomalies and sea surface temperature (SST) anomalies averaged over 5°S to 5°N, for the past 36 months across the equatorial Pacific Ocean.
Seasonal OLR and SST Climatology
This is a Hovmoller diagram (Longitude x Time) showing the outgoing longwave radiation (OLR) seasonal (three-month) climatology and sea surface temperature (SST) seasonal climatology averaged over 5°S to 5°N across the equatorial Pacific Ocean.
Weekly Sea Surface Temperature Anomaly
This is a Hovmoller diagram (Longitude x Time) showing weekly average sea surface temperature (SST) anomalies averaged over 5°S to 5°N, for the past year across the equatorial Pacific Ocean.
Monthly Sub-Surface Temperature Anomaly
This is a Hovmoller diagram (Longitude x Time) showing monthly potential temperature anomalies at depths of 55 and 155 meters, averaged over 5°S to 5°N, for the past year across the equatorial Pacific Ocean.
Equatorial Indian & Pacific Ocean 200 hPa Velocity Potential Anomaly
This is a Hovmoller diagram (Longitude x Time) showing pentad (five-day) running average velocity potential anomalies at 200 hPa averaged over 5°S to 5°N, for the past 180 days across the equatorial Indian and Pacific Oceans.
925 hPa Pentad Zonal Wind Anomaly
This is a Hovmoller diagram (Longitude x Time) showing pentad (five-day) average zonal wind anomalies at 925 hPa averaged over 5°S to 5°N, for the past year across the equatorial Pacific Ocean.
925 hPa Pentad Observed Zonal Wind
This is a Hovmoller diagram (Longitude x Time) showing pentad (five-day) average zonal winds at 925 hPa averaged over 5°S to 5°N, for the past year across the equatorial Pacific Ocean.
SST Plots
Monthly Sea Surface Temperature Greater Than 28°C
This map displays the extent of monthly sea surface temperatures for the globe that are 28°C or above for the month indicated, compared to the mean extent for the 1971-2000 base period for the same month of the year.
Change in Sea Surface Temperature Anomaly from Previous Month
This map displays the difference in sea surface temperature anomaly from the previous month for the Pacific Ocean.
Monthly Sea Surface Temperature Anomaly
This map displays monthly sea surface temperature anomalies for the Pacific Ocean.
Three-Month Standardized Monthly SST Anomaly Persistence
This map shows the number of months out of the three months indicated in which the standardized sea surface temperature anomaly in the Pacific Ocean exceeded +1 standard deviation or fell below -1 standard deviation of the 1971-2000 mean.
Six-Month Standardized Monthly SST Anomaly Persistence
This map shows the number of months out of the six months indicated in which the standardized sea surface temperature anomaly in the Pacific Ocean exceeded +1 standard deviation or fell below -1 standard deviation of the 1971-2000 mean.
Seasonal Sea Surface Temperature Anomaly
This map displays seasonal (three-month) sea surface temperature anomalies for the Pacific Ocean.
Monthly Standardized Sea Surface Temperature Anomaly
This map displays monthly standardized sea surface temperature anomalies for the Pacific Ocean for the month indicated.
Standardized Change in Sea Surface Temperature Anomaly from Previous Month
This map displays the change in sea surface temperature anomaly from the previous month divided by the standard deviation of the month-to-month change for the given month over the 1950-present base period centered on the tropical Pacific Ocean.
Weekly Sea Surface Temperature Anomaly
This map displays weekly sea surface temperature anomalies for the tropical Pacific Ocean.
Weekly Sea Surface Temperature Anomaly Animation
This map displays an animation of weekly sea surface temperature anomalies for the tropical Pacific Ocean over a 20-week period.
Surface Wind
925 hPa Monthly Wind Vector Anomaly
This map displays monthly vector wind anomalies at the 925hPa pressure level over the tropical Pacific Ocean.
Pentad Zonal Wind Component - Niño1+2 Region
This plot displays a time series of pentad (5-day average) zonal wind at the 925 hPa pressure level averaged over the Niño1+2 region, and the 1981-2010 climatology of the same, over the past year.
Pentad Zonal Wind Component - Niño3.4 Region
This plot displays a time series of pentad (5-day average) zonal wind at the 925 hPa pressure level averaged over the Niño3.4 region, and the 1981-2010 climatology of the same, over the past year.
Pentad Zonal Wind Component - Niño3 Region
This plot displays a time series of pentad (5-day average) zonal wind at the 925 hPa pressure level averaged over the Niño3 region, and the 1981-2010 climatology of the same, over the past year.
Pentad Zonal Wind Component - Niño4 Region
This plot displays a time series of pentad (5-day average) zonal wind at the 925 hPa pressure level averaged over the Niño4 region, and the 1981-2010 climatology of the same, over the past year.
Thermocline
Equatorial Pacific Monthly Thermocline Animation
This is a monthly animation over the past year of the equatorial Pacific thermocline, shown as a longitude x depth plot of GODAS potential temperature averaged over 5°S to 5°N, and spanning the Pacific from 121°E to 79°W from the surface to a depth of 350 meters.
Latitude-Depth Section of Equatorial Pacific Thermocline at 150°W
This figure is a latitude-depth section of oceanic potential temperature monthly anomalies along the tropical Pacific thermocline at 150°W.
Change in Equatorial Pacific Temperature Anomaly from Previous Month
This figure is a longitude-depth section of the difference of oceanic potential temperature monthly anomalies from one month to the next along the equatorial Pacific thermocline.
Longitude-Depth Section of Potential Temperature Anomaly Along the Equatorial Pacific Thermocline
This figure is a longitude-depth section of oceanic potential temperature monthly anomalies averaged from 5°S to 5°N along the equatorial Pacific thermocline.
Animation of Longitude-Depth Section of Potential Temperature Anomaly Along the Equatorial Pacific Thermocline
This figure displays an animation of a longitude-depth section of oceanic potential temperature monthly anomalies averaged from 5°S to 5°N along the equatorial Pacific thermocline.
Standardized Anomaly of the Depth of the 20°C Isotherm
This figure is a longitude-time Hovmoller diagram of the monthly standardized anomaly of the depth of the 20°C isotherm in the equatorial Pacific Ocean.
Central Equatorial Pacific Heat Storage and Niño 3.4 SST
This figure displays time series plots of percentiles of oceanic heat storage seasonal anomalies in the top 300 meters of the central equatorial Pacific Ocean, and percentiles of Niño 3.4 SST monthly anomalies from 1982 to the present.
Time Series
Fraction of Area of Equatorial Pacific with SST Greater than or Equal to 28°C
This figure displays a time series, in the form of vertical color bars, of the fraction of the area in the equatorial Pacific Ocean from 10°S to 10°N latitude and 85°W to 180°W longitude in which weekly sea surface temperatures are 28°C or greater.
Central Equatorial Indian Ocean Index
This is a time series of the three-month running average of the standardized Central Equatorial Indian Ocean Index (CEI) -- monthly mean sea surface temperature anomalies averaged over the region 0° to 15°S latitude and 50°E to 80°E longitude.
Equatorial Pacific Weekly Sea Surface Temperature Hovmoller
This is a time-longitude Hovmoller diagram of weekly sea surface temperature, averaged from 10°S to 10°N latitude, across the equatorial Pacific Ocean from 135°E to 85°W, and with time extending from November 1981 to the present.
Anomalous Depth of the Equatorial Pacific Thermocline: East-Central Pacific
This plot displays three-month running average time series of warm water volume across the east-central equatorial Pacific Ocean based upon the standardized anomalous depth of the equatorial Pacific thermocline, and the standardized NINO3.4 sea surface temperature anomaly from 1982 to present.
Anomalous Depth of the Equatorial Pacific Thermocline: Full Pacific
This plot displays three-month running average time series of warm water volume across the equatorial Pacific Ocean based upon the standardized anomalous depth of the equatorial Pacific thermocline, and the standardized NINO3.4 sea surface temperature anomaly from 1982 to present.
Anomalous Depth of the Equatorial Pacific Thermocline: Western Pacific
This plot displays three-month running average time series of warm water volume across the western equatorial Pacific Ocean based upon the standardized anomalous depth of the equatorial Pacific thermocline, and the standardized NINO3.4 sea surface temperature anomaly from 1982 to present.
North Tropical Atlantic Index
This is a time series of the three-month running average of the standardized North Tropical Atlantic Index (NATL) -- monthly mean sea surface temperature anomalies averaged over the region 10°N to 20°N latitude and 79°W to 20°W longitude.
North Tropical Atlantic Index and NINO3 Index
On this plot are time series of the three-month running average of the standardized North Tropical Atlantic Index (NATL) (dotted line; monthly mean sea surface temperature anomalies averaged over the region 10°N to 20°N latitude and 79°W to 20°W longitude), the three-month running average of the standardized NINO3 index (dashed line; monthly mean SST anomalies averaged over the region 5°S to 5°N latitude, 150°W to 90°W longitude), and the standardized difference between NATL and NINO3 (solid red line; NATL minus NINO3).
Niño 3.4 SST Anomaly and Equatorial Central/Eastern Pacific 925 hPa Zonal Wind Anomaly
These are time series of the three-month running average of standardized anomalies of the monthly zonal wind at 925 hPa averaged over the equatorial Pacific Ocean (5°S to 5°N latitude and 150°E to 90°W longitude) and the three-month running average of standardized anomalies of monthly sea surface temperature anomalies averaged over the NINO3.4 region in the equatorial Pacific (5°S to 5°N latitude and 170°W to 120°W longitude) over the past 25 years.
Southern Oscillation Index (SOI) and Equatorial SOI
This plot shows time series of the three-month running average of the Equatorial Southern Oscillation Index (EQ_SOI; in red) and the three-month running average of the Southern Oscillation Index (SOI; in blue) for the past 20 years.
Five-Month Running Average Southern Oscillation Index
This figure displays a time series of the five-month running average of the standardized Southern Oscillation Index (SOI) from January 1951 to present.
Equatorial Pacific Monthly Standardized Sea Level Pressure Anomaly Hovmoller
This is a longitude-time Hovmoller diagram of standardized sea level pressure anomaly, averaged from 5°S to 5°N latitude, across Indonesia and the equatorial Pacific Ocean from 90°E to 80°W, over the past two years.
Column-Average Tropospheric Temperature Anomaly over the Tropics
This is a map of monthly tropospheric temperature anomaly in the global tropics, averaged from 850 hPa to 200 hPa.
Standardized Anomalies of Average Tropical Tropospheric Temperature and Niño 3.4 SST
This plot displays time series of the three-month running average of standardized tropical tropospheric temperature anomalies (in blue) and the three-month running average of standardized Niño 3.4 sea surface temperature anomalies (in red).
Average Tropical Tropospheric Temperature Anomaly
This is a longitude-pressure section of monthly tropospheric temperature anomaly, averaged from 25°S to 25°N latitude, plotted across all longitudes, and from 850 hPa to 200 hPa.
Tropical Atmospheric Circulation
Seasonal Precipitation and Standardized Streamfunction Anomalies
This is a map of seasonal (3-month) CAMS-OPI precipitation anomaly from the long-term mean, and seasonal-average standardized streamfunction anomaly (select from 925 hPa and 200 hPa pressure levels) over the tropical Indian and Pacific Oceans.
Seasonal Precipitation and Standardized Velocity Potential Anomalies and Divergent Wind
This is a map of seasonal (3-month) CAMS-OPI precipitation anomaly from the long-term mean, and seasonal-average standardized velocity potential anomaly (select from 925 hPa and 200 hPa pressure levels), and the divergent part of the wind (vectors) over the tropical Indian and Pacific Oceans.