Premium
Effect of geomagnetic activity on the northern annular mode: QBO dependence and the Holton‐Tan relationship
Author(s) -
Maliniemi V.,
Asikainen T.,
Mursula K.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd024460
Subject(s) - earth's magnetic field , climatology , quasi biennial oscillation , atmospheric sciences , mode (computer interface) , oscillation (cell signaling) , environmental science , physics , geology , stratosphere , chemistry , magnetic field , quantum mechanics , computer science , operating system , biochemistry
Mutually conflicting results have been presented in earlier studies on the long‐term relation of geomagnetic activity (GA) and the winter northern annular mode (NAM) and its modulation by quasi‐biennial oscillation (QBO). Some studies have found a stronger positive relation in the easterly phase of the QBO, while in other studies a stronger positive relation was found in the westerly phase of the QBO. Using QBO reconstruction from the beginning of the twentieth century we find that the QBO modulation of the GA‐NAM relation is temporally variable, which explains the earlier, seemingly differing results. Positive relation is found to be valid in the easterly QBO phase at 30 hPa for the whole twentieth century. We also find that the QBO at 30 hPa better represents the Holton‐Tan relation for the surface circulation and that the Holton‐Tan relation is only observed during early/mid winter, while an anti‐Holton‐Tan relation is found in the late winter for strong geomagnetic activity. These results emphasize the systematic response of NAM to particle precipitation during the entire twentieth century and underline the importance of considering the preconditioning of the atmosphere when studying the solar‐related effects upon climate.