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Advection fog

A type of fog formed when warm, moist, stable air moves over a far cooler surface. It is most commonly found over cool sea areas in spring and summer, but does occasionally form over land in the winter, especially when the ground is frozen or covered by snow.

Aurora

Taking its name from the Latin for dawn, aurora is the phenomenon of visible light being emitted by the high atmosphere, caused when charged particles emitted by the sun are deflected by the Earth’s permanent magnetic field. In Britain, aurora usually appears as a grey-white glow on the northern horizon. The terms ‘aurora borealis’ (or northern lights) and ‘aurora australis’ (or southern lights) are applied to the occurrence of aurora in the northern and southern hemispheres respectively.