NCAR Climate Data Guide Content with Tag: Circulation

Hurrell North Atlantic Oscillation (NAO) Index (station-based)
Years of Record: 1865/01 to 2017/06
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...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly,Seasonal,Annual Domain: Atlantic Ocean
Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index
Years of Record: 1899/01 to 2018/03
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...
Main variables and Earth System components:
Formats: ascii Timestep: Seasonal Domain: Atlantic Ocean, NH - Northern Hemisphere, Pacific Ocean
Marshall Southern Annular Mode (SAM) Index (Station-based)
Years of Record: 1957/01 to 2015/09
The station-based index of the Southern Annular Mode (SAM) is based on the zonal pressure difference between the latitudes of 40S and 65S.  As such, the SAM index measures a "see-saw" of atmospheric mass between the middle and high latitudes of the Southern Hemisphere.  Positive values of...
Main variables and Earth System components:
Formats: ascii Domain: Antarctic, SH - Southern Hemisphere, Southern Ocean
See Expert Guidance by Marshall, Gareth
MJO: Madden-Julian Oscillation Diagnostics
"The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection.[1][2] Rather than being a standing pattern (like ENSO) it is a traveling...
North Pacific (NP) Index by Trenberth and Hurrell; monthly and winter
Years of Record: 1899/01 to 2018/03
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...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly,Seasonal Domain: NH - Northern Hemisphere, Pacific Ocean
Climate Data Guide Image: QBO
QBO: Quasi-Biennial Oscillation
Years of Record: 1953/01 to 2012/09
The quasi-biennial oscillation (QBO) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly Domain: Tropics
Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)
Years of Record: 1866/01 to 2016/01
The Southern Oscillation Index (SOI) is a time series used to characterize the large scale sea level pressure (SLP) patterns in the tropical Pacific. Monthly mean SLP at Tahiti [T] and Darwin [D] are used. An optimal SOI can be constructed. It consists of  [T-D] which is a measure of the large...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Monthly Domain: Australia, Pacific Ocean, Tropics
See Expert Guidance by Trenberth, Kevin
Subscribe to Recent Climate Data Guide content with Tag: Circulation