20CR Climate Indices: North Pacific Index (NP)
This mode describes variability of the north pacific atmosphere.
Correlation of 20CRV3 January SLP with the NP 20CR Index. Created with the Atmospheric WRIT Correlation Tool.
Times-series from the WRIT Time-series Plotting Tool
Description
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.Temporal Coverage
- Monthly values: 1851/01 to 2011 (V2c)
- Monthly values: 1871 to 2012 (V2)
- Update Status:Static: Static
Data Notes
- Units: mb
- Missing data value: -99.0
Time-series List
-
NP index: 20CRV2c Standard PSL Format (What is standard format?)
- NP index: 20CRV2 Standard PSL Format (What is standard format?)
- NP index 20CRV2c: Standard PSL Format (1948 onwards version)(What is standard format?)
Mli>NP index 20CRV2: Standard PSL Format (1948 onwards version)(What is standard format?)
Usage Restrictions
- None
Caveats
- None
Related Time-series
Links
- AAO from the 20th Century Reanalysis.
- AAO/NP from JISAO
- NOAA/NCEP Climate Prediction Center (CPC) AAO monitoring page
Original Source
- Time-series was calculated at NOAA/PSL.
Time-series source dataset(s)
- Input data for the mode calculation is the 20CR Datasets.
Citation
- Cite PSL
References
- 20CR citations
- Thompson D. W.J. and J.M. Wallace:2000: Annular Modes in the Extratropical Circulation. Part I: Month-to-Month Variability:
J. of Climate , 13, 1000-1016.