North Pacific (NP) Index by Trenberth and Hurrell; Monthly and Winter

The North Pacific Index (NP index or NPI) is the area-weighted sea level pressure over the region 30°N-65°N, 160°E-140°W. The NP index is defined to measure interannual to decadal variations in the atmospheric circulation. The dominant atmosphere-ocean relation in the North Pacific is one where atmospheric changes lead changes in sea surface temperatures by one to two months. However, strong ties exist with events in the tropical Pacific, with changes in tropical Pacific SSTs leading SSTs in the north Pacific by three months.

To Access Resource:

Questions? Email Resource Support Contact:

  • Phillips, Adam
    asphilli@ucar.edu
    UCAR/NCAR - Climate and Global Dynamics Laboratory

Temporal Range

  • Begin:  1899-01-01
    End:  2017-08-31

Keywords

Resource Type dataset
Temporal Range Begin 1899-01-01
Temporal Range End 2017-08-31
Temporal Resolution Monthly; Seasonal
Bounding Box North Lat 65
Bounding Box South Lat 30
Bounding Box West Long 160
Bounding Box East Long -140
Spatial Representation N/A
Spatial Resolution N/A
Related Links N/A
Additional Information N/A
Resource Format NETCDF
Standardized Resource Format NetCDF
Asset Size N/A
Legal Constraints

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Access Constraints NP Index Data provided by the Climate Analysis Section, NCAR, Boulder, USA, Trenberth and Hurrell (1994). Updated Regularly. Accessed DD Month YYYY [list date you accessed the data].
Software Implementation Language N/A

Resource Support Name Phillips, Adam
Resource Support Email asphilli@ucar.edu
Resource Support Organization UCAR/NCAR - Climate and Global Dynamics Laboratory
Distributor N/A
Metadata Contact Name Phillips, Adam
Metadata Contact Email asphilli@ucar.edu
Metadata Contact Organization UCAR/NCAR - Climate and Global Dynamics Laboratory

Author Hurrell, James
Publisher UCAR/NCAR - Climate and Global Dynamics Laboratory
Publication Date 1995-01-01
Digital Object Identifier (DOI) Not Assigned
Alternate Identifier N/A
Resource Version N/A
Topic Category climatologyMeteorologyAtmosphere
Progress onGoing
Metadata Date 2023-11-12T10:05:02
Metadata Record Identifier climatedataguide.ucar.edu::node.660
Metadata Language eng
Suggested Citation Hurrell, James. (1995). North Pacific (NP) Index by Trenberth and Hurrell; Monthly and Winter. UCAR/NCAR - Climate and Global Dynamics Laboratory. https://climatedataguide.ucar.edu/node/660. Accessed 25 October 2025.

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