Skip Navigation Links 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center

HOME > Monitoring and Data > Monitoring Weather & Climate > Blocking > Background > Blocking Stratified By ENSO Cycle
Using the blocking index of Tibaldi and Molteni (1990) we can consider the frequency of DJF "blocked days" for Neutral, Warm and Cold episodes as defined by the magnitude of the SST anomalies in the tropical Pacific. Cold episodes are defined as [C+,C], warm episodes [W+,W], and neutral episodes as [W-,C-,N]. For each panel the number of DJF seasons is shown in square brackets. We have also included in the middle panel on the right-hand side a plot of the neutral episodes defined simply as [N]. This can be compared with the middle left-hand side panel where neutral episodes have been defined as [W-,C-,N]. In each panel the DJF 51 year average has been plotted in red for ease of comparison.
Frequency of December-January-February blocked day for Neutral, Warm and Cold ENSO episodes

NOAA/ National Weather Service
NOAA Center for Weather and Climate Prediction
Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740
Page Author: Climate Prediction Center Internet Team
Page last modified: January 5, 2006
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities