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| Titel |
The interplanetary magnetic field influences middle-latitude surface atmospheric pressure |
| VerfasserIn |
Mai Mai Lam, Gareth Chisham, Mervyn Freeman |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074179
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| Zusammenfassung |
| Results have been published over several decades that indicate a meteorological response in
the polar regions to fluctuations in the east-west component of the interplanetary magnetic
field (IMF), By. There is evidence that this Sun-weather coupling occurs via the global
atmospheric electric field. It has been assumed that the effect maximises at high latitudes and
is negligible at low and mid latitudes because the IMF-induced convection electric
field is concentrated in the polar ionospheres. However, the spatial variation of the
IMF-weather coupling has not previously been investigated in detail, neither have the
global consequences of such forcing on the atmosphere. Here we demonstrate a
previously unrecognised influence of IMF By on mid-latitude surface pressure. The
difference between the mean surface pressure for high positive and high negative
values of IMF By possesses a statistically-significant mid-latitude wave structure,
similar in location and form to the cyclones and anti-cyclones produced by the action
of atmospheric Rossby waves on the jet stream. Thus our results indicate that a
mechanism that is known to produce atmospheric responses to the IMF in the polar
regions is also able to modulate pre-existing weather patterns at mid-latitudes. A
relatively localised and small amplitude solar influence on the upper atmosphere
could therefore have an important effect, via the nonlinear evolution of storm tracks,
on critical processes such as European climate and the breakup of Arctic sea ice. |
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