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20CR Climate Indices:NP

The North Pacific (NP) Index is the area-weighted sea level pressure over the region 30N-65N, 160E-140W. 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(from NCAR climate data guide).
Spatial pattern of the 20CRV2 NP. Correlation uses January 1948-2011 monthly SLP from the NCEP/NCAR R1 dataset.
Calculation Method:
Index is the area-weighted sea level pressure over the region 30N-65N, 160E-140W.
Time Interval: Monthly
Time Coverage: 1871 to 2012
Update Status: none

Get Data:
NP index: Standard PSD Format (What is standard format?)
NP index: Standard PSD Format (1948 onwards version)(What is standard format?)
Data is calculated at PSD using method above.
  1. The Twentieth Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center managed by Lawrence Berkeley National Laboratory and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively. Papers using the Twentieth Century Reanalysis Project dataset are requested to include the following text in their acknowledgments: "Support for the Twentieth Century Reanalysis Project dataset is provided by the U.S. Department of Energy, Office of Science Innovative and Novel Computational Impact on Theory and Experiment (DOE INCITE) program, and Office of Biological and Environmental Research (BER), and by the National Oceanic and Atmospheric Administration Climate Program Office."
  2. Trenberth and Hurrell (1994) Decadal atmosphere-ocean variations in the Pacific. Climate Dynamics, Vol. 9, p 303-319.
Other Links
  1. NCAR Climate Data Guide on the NP.