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Northern and Southern Hemisphere Blocking Index from NOAA/Climate Prediction Center

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Abstract: [Source: NOAA Climate Prediction Center, ]

The blocking index of Tibaldi and Molteni (1990) was modified from that of Lejenas and Okland (1983). The index is local and instantaneous, ideally suited for real-time atmospheric monitoring, isolating regions of easterly flow at 500 hPa associated with high-latitude blocks.

This dataset uses the blocking index calculation for the northern hemisphere, however the index can be easily modified to examine blocking in the southern hemisphere. Blocking in the southern hemisphere typically occurs at lower latitudes when compared with the northern hemisphere. The index follows Tibaldi et al. (1994).
Related URL
Description: Access to blocking index data, documentation, and graphs.
Geographic Coverage
Spatial coordinates   
  N: 90.0   S: 0.0   E: 180.0   W: -180.0
Min Altitude: 0 HPA Max Altitude: 500 HPA
  N: -0.0   S: -90.0   E: 180.0   W: -180.0
Min Altitude: 0 HPA Max Altitude: 500 HPA

Data Set Citation
Dataset Originator/Creator: Tibaldi, S., and F. Molteni
Dataset Title: Blocking Index
Dataset Series Name: NOAA/NWS/CPC Indices and Forecasts
Dataset Release Date: ongoing
Dataset Release Place: Camp Springs, MD
Dataset Publisher: NOAA National Weather Service, Center for Climate Prediction
Online Resource:
Temporal Coverage
Start Date: 2002-01-01
Data Resolution
Temporal Resolution: daily
Data Set Progress
Originating Center
Distribution Media: online www
Distribution Format: ascii
Fees: none
Email: Ed.Olenic at
Lejenas, H., and H. Okland (1983), Characteristics of Northern Hemisphere blocking as determined from a long time series of observational data, Tellus, 35A, 350-362
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Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2003-02-11
Last DIF Revision Date: 2017-08-24