climatedataguide.ucar.edu::node.658 eng dataset Phillips, Adam UCAR/NCAR - Climate and Global Dynamics Laboratory asphilli@ucar.edu pointOfContact 2023-11-12T10:05:02 ISO 19115 ISO19115:2003/Cor 1 2006 https://climatedataguide.ucar.edu/node/658 http://climatedataguide.ucar.edu/node/652 Hurrell North Atlantic Oscillation (NAO) Index (Station-Based) The NAO Index, and alternative to the NAM. information Hurrell Wintertime SLP-based Northern Annular Mode (NAM) Index 1995-01-01 publication Hurrell, James UCAR/NCAR - Climate and Global Dynamics Laboratory author UCAR/NCAR - Climate and Global Dynamics Laboratory publisher 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, the main difference is larger amplitude anomalies over the North Pacific of the same sign as those over the Atlantic. This feature gives the NAM a more annular (or zonally-symmetric) structure. Positive values of the NAM are associated with lower-than-normal sea level pressures over the Arctic and westerly wind anomalies along ~55º-60ºN. onGoing Phillips, Adam UCAR/NCAR - Climate and Global Dynamics Laboratory Associate Scientist asphilli@ucar.edu pointOfContact NETCDF Dataset theme Resource Type 2017-05-10 publication DataCite originator EARTH SCIENCE > CLIMATE INDICATORS > ATMOSPHERIC/OCEAN INDICATORS > TELECONNECTIONS > ARCTIC OSCILLATION > AO GCMD 2017-07-18 revision GCMD originator Dash and its services comply with policies set by UCAR and NCAR. citation: NAM Index Data provided by the Climate Analysis Section, NCAR, Boulder, USA. Updated regularly. Accessed DD Month YYYY [list date you accessed the data]. eng climatologyMeteorologyAtmosphere Seasonal true -180 180 20 90 1899-01-01 2016-03-31 TXT asNeeded