NGAO Index

The Northern Gulf of Alaska Oscillation index (NGAO) describes the strength of the cyclonic circulation in the Gulf of Alaska and therefore the intensity of the offshore upwelling in the Alaskan gyre and coastal downwelling (Hauri et al., 2021). 

Northern Gulf of Alaska Oscillation Index (NGAO) derived from satellite-observed Absolute Dynamic Topography. Generated using E.U. Copernicus Marine Service Information https://doi.org/10.48670/moi-00149 and https://doi.org/10.48670/moi-00148.

A negative NGAO phase is characterized by a strong cyclonic circulation leading to a strong offshore upwelling and nearshore downwelling.  

A positive NGAO phase is characterized by a weak cyclonic circulation leading to a weak offshore upwelling and nearshore downwelling.

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Cite the NGAO index :

Hauri, C., Pagès, R., McDonnell, A. M. P., Stuecker, M. F., Danielson, S. L., Hedstrom, K., Irving, B., Schultz, C., & Doney, S. C. (2021). Modulation of ocean acidification by decadal climate variability in the Gulf of Alaska. Communications Earth & Environment, 2(1), 191. https://doi.org/10.1038/s43247-021-00254-z