substormn.
/ˈsʌbstɔːm/, U.S. /ˈsəbˌstɔrm/ 1. Meteorology. A minor or subsidiary storm. Now rare.In quot. 1875 figurative.
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1867 A. Buchan Handy Bk. Meteorol. xi. 175 These storms may thus be regarded as secondary storms or sub-storms within the area of the more general storm passing over Europe at the time.
1875 Harper's New Monthly Mag. Oct. 696 There arose a wild chorus of groaning, mingled with a sub-storm of hissing.
1892 I. P. Noyes Meteorology 11 They are termed ‘locals’, for the reason that they are little sub-storms taking place here and there quite a distance from..the centre of the ‘low’.
1996 Jrnl. N. Amer. Benthol. Soc. 15 24/1 This 6-d period was a sequence of three small storms spaced 6–24 hours apart, which could be treated as three separate sub-storms.
2. Atmospheric Physics. A localized disturbance of the earth's magnetic field in high latitudes, typically lasting a few hours and causing increased auroral activity and other upper atmospheric phenomena. Cf. geomagnetic storm n. at geomagnetic adj. Compounds.
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the world > the earth > weather and the atmosphere > weather > bad weather > [noun] > a disturbance of the elements > magnetic, in polar regions
substorm1961
1961 S.-I. Akasofu & S. Chapman in Jrnl. Geophysical Res. 66 1339/2 Each such event, which Birkeland..called a polar elementary storm, is here called a DP substorm.
1969 New Scientist 25 Sept. 669/3 These are the ‘substorms’ which manifest themselves as aurorae and associated magnetic disturbances.
1994 Q. Jrnl. Royal Astron. Soc. 35 481 A possible mechanism for the increase is the injection of plasma from the magnetotail into the auroral ionosphere during magnetospheric substorms.
2007 Guardian 15 Feb. 9/1 Most of the time, the northern lights make up a steady band stretching from east to west but every few hours the energy released by the magnetic field intensifies into a substorm.
This entry has been updated (OED Third Edition, June 2012; most recently modified version published online March 2022).
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