El Niño Southern Oscillation (ENSO)

ENSO's effect on climate

*Plot effects on seasonal climate extremes of temperature and precipitation over the United States ("Risk Plots")

Given an El Nino or La Nina condition, what are the odds of getting a warm versus a cold season? A wet versus a dry season?

*Plot global composites of temperature and precipitation throughout a El Nino and La Nina cycle.

Plot composite signals based on historical data of global surface temperature and precipitation
How do the precipitation and geopotential heights for a particular year/month compare to those one would expect from ENSO (assuming a linear ENSO effect)?

*Monthly composites of atmospheric variables for El Niño and La Niña.

What does the seasonal cycle of different variables during an average (composite) El Nino and La Nina look like?

*Animation of Global Surface Temperature During a Warm Event

Posters

These "posters" show the comparison of actual climate throughout the year during a El Nino and La Nina Event to those expected from a risk analysis of the historical climate record for the last 100 years. Surface temperature and precipitation are plotted. Note that these posters are large.

Effects on global temperature and precipitation:

Select temperature or precipitation composite based on season and phase of ENSO:
Type of Event: Warm Cold

Variable: Temperature Precipitation

ENSO Phase (Year corresponds to MIDDLE month in seasonal average):
Year preceding start of event (starts Mar-May)
Year event begins (composite events start in autumn; 82-83 El Niño starts in 1982 for example)
Year after event begins (for 1982-83 event, would be 83)ends Aug-Oct)
Months:
Animate all maps

Temperature and precipitation anomalies have been composited for El Niño and La Niña years (from Kiladis and Diaz). Composites were done for overlapping seasons from the year preceding a peak event to the year following the peak event. The dataset used was the GHCN 5°° dataset available at NCDC (1857-1994). Anomalies were computed by removing the monthly means from 1951 to 1980 but were not standardized. Units are millimeters/month for precipitation and ° for temperature
You can use these plots in publications, though we ask that you acknowledge the Physical Sciences Laboratory in the publication. For example, "Image provided by the NOAA/ESRL Physical Sciences Laboratory, Boulder Colorado from their Web site at http://www.cdc.noaa.gov/."