Pacific Fisheries Environmental Laboratory

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Why the NOI?

The SOI is a good indicator of tropical variations related to El Niño and La Niña, but it may not be the best way to represent global interannual to decadal variability, particularly at extratropical latitudes. Here are two main reasons why:

  • The extratropical impacts of El Niño/La Niña are poorly understood and more correlative than mechanistically linked

  • The SOI does not have a direct physical link to the northeast Pacific region.

It is more straightforward and intuitive to use an index that complements the SOI, but also has a physical connection to the extratropics. Alternatives and supplements to the SOI should be considered, both for extratropical diagnosis of interannual/decadal variability and to better understand the processes responsible for global-scale shifts in atmospheric and oceanic conditions.

NOI definitions diagram

The NOI ia a reliable indicator for monitoring and predicting climate fluctuations, and their physical and biological consequences in the Northeast Pacific.

NOI homepage NOI Computation red arrowWhy a new index? NOI background
View/Download NOI,SOI,SOI* timeseries Citing the NOI ERD home page

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