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Q burstAn electromagnetic transient launched by a lightning discharge of large amplitude within the earth–ionosphere cavity. Originally named by Toshio Ogawa (1967), the “Q” connotes “quiet” and characterizes a transient in which the fundamental 8-Hz mode of the Schumann resonances is the dominant contributor. In general, a mix of Schumann modes makes up a Q burst.
Ogawa, T., et al., 1967: Worldwide simultaneity of occurrence of a Q-type ELF burst in the Schumann resonance frequency range. J. Geomag. Geoelectr., 19, 377, 384.
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Q noiseQuasi-continuous sequences of VHF (very high frequency) radiation emanating from lightning that is associated with high-speed K-change activity along pre-ionized lightning channels. The process was named by David Proctor (1974).
Proctor, D., 1974: VHF radio pictures of lightning. CSIR Special Report, No. TEL 120, Pretoria, South Africa.
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Q vectorA horizontal vector, arising in quasigeostrophic and semigeostrophic theory, the divergence of which appears on the right-hand side of the omega equation. In the context of f-plane (i.e., the Coriolis parameter f is assumed constant) quasigeostrophic theory, the Q vector is defined as  where g is the acceleration of gravity, θ0 a constant reference value of the potential temperature, vg the horizontal geostrophic wind, ∇p the horizontal gradient operator on a constant-pressure surface, and θ the potential temperature. In the context of f-plane semigeostrophic theory, the definition of the Q vector is identical except that the physical coordinates (x, y) are replaced by the geostrophic coordinates (X, Y). The Q vector tends to point in the direction of rising air. If Q points toward warm air, the geostrophic flow is frontogenetic. If Q points toward cold air, the geostrophic flow is frontolytic.
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