Climate data guide content with tag Phillips, Adam
Hurrell North Atlantic Oscillation (NAO) Index (PC-based)
Years of record
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The principal component (PC)-based indices of the North Atlantic Oscillation (NAO) are the time series of the leading Empirical Orthogonal Function (EOF) of SLP anomalies over the Atlantic sector, 20°-80°N, 90°W-40°E. These indices are used to measure the NAO throughout the year, tracking the seasonal movements of the Icelandic low and Azores high. These movements…
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Formats
- ascii
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Timestep
- Monthly, Seasonal, Annual
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Domain
- Atlantic Ocean
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James, Phillips, Adam
Hurrell North Atlantic Oscillation (NAO) Index (station-based)
Years of record
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The winter (December thru March) station-based index of the NAO is based on the difference of normalized sea level pressure (SLP) between Lisbon, Portugal and Stykkisholmur/Reykjavik, Iceland since 1864. Positive values of the NAO index are typically associated with stronger-than-average westerlies over the middle latitudes, more intense weather systems over…
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Formats
- ascii
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Timestep
- Monthly, Seasonal, Annual
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Domain
- Atlantic Ocean
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James, Phillips, Adam
Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index
Years of record
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The NAM (or Arctic Oscillation) is defined as the first EOF of NH (20°-90°N) winter SLP data. It explains 23% of the extended winter mean (December-March) variance, and it is clearly dominated by the NAO structure in the Atlantic sector. Although there are some subtle differences from the NAO regional pattern over the Atlantic and Arctic (see Figure 1 below), the main…
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Formats
- ascii
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Timestep
- Seasonal
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Collections
- N/A
Experts contributing reviews
- Phillips, Adam
North Pacific (NP) Index by Trenberth and Hurrell; monthly and winter
Years of record
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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…
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Formats
- ascii
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Timestep
- Monthly, Seasonal
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James, Phillips, Adam