Magnetic Variation

Magnetic Variation: The angle variation between magnetic north and true north.
Mare's Tail: A name given to wispy cirrus clouds.
Mammatus Cloud: A puffy ominous looking but harmless cloud which forms underneath the cloudbase from decending air.

Sq - The solar daily magnetic variations on quiet days. It is determined from the records at geomagnetic stations for days that are believed free of noncyclic disturbances.

See also: Meteor, Mixing, Meteorology, Period, Ocean