Secular variation

Secular variation

The secular variation (or secular trend) of a time series is its long-term non-periodic variation, as opposed to its periodic variation. Of course, whether something is perceived as a secular variation or not depends on the available timescale: what appears to be a secular variation over a time scale of centuries can turn out to be a periodic variation over a time scale of millions of years. Natural quantities often have both periodic and secular variations.

The term "secular variation" is used wherever time series are applicable such as in economics, operations research, astronomy ( particularly celestial mechanics), etc.

Jack McCormac states in Surveying, 5th ed.:"The angle of declination [the angle by which astronomic north varies with magnetic north] at a particular location is not constant but varies with time. For periods of approximately 150 years, there is a gradual unexplainable shift in the earth's magnetic fields in one direction after which a gradual drift occurs in the other direction to complete the cycle in the next 150-year period. This variation, called "secular variation", can be large. There is no known method of accurately predicting the secular change and all that can be done is to make observations of its magnitude at various places around the world. Records kept in London for several centuries show a range of magnetic declination from 11oE in 1580 to 24oW in 1820. The time period between extreme eastern and western declinations varies with locality. It can be as short as 50 years or even less and as long as 180 years or more."

For example, in the business operating cycle, revenue might fluctuate during the fiscal year. Experienced management could ignore the cyclical fluctuation in revenue and concentrate instead on the larger trend from year to year, hoping to see a secular trend upward.

ee also

*Market trends


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  • secular variation — šimtmetinis svyravimas statusas T sritis fizika atitikmenys: angl. secular variation vok. säkulare Schwankung, f rus. вековое колебание, n; вековой ход, m pranc. marche séculaire, f; variation progressive, f; variation séculaire, f …   Fizikos terminų žodynas

  • secular — adj. & n. adj. 1 concerned with the affairs of this world; not spiritual or sacred. 2 (of education etc.) not concerned with religion or religious belief. 3 a not ecclesiastical or monastic. b (of clergy) not bound by a religious rule. 4… …   Useful english dictionary

  • variation progressive — šimtmetinis svyravimas statusas T sritis fizika atitikmenys: angl. secular variation vok. säkulare Schwankung, f rus. вековое колебание, n; вековой ход, m pranc. marche séculaire, f; variation progressive, f; variation séculaire, f …   Fizikos terminų žodynas

  • variation séculaire — šimtmetinis svyravimas statusas T sritis fizika atitikmenys: angl. secular variation vok. säkulare Schwankung, f rus. вековое колебание, n; вековой ход, m pranc. marche séculaire, f; variation progressive, f; variation séculaire, f …   Fizikos terminų žodynas

  • Secular variations of the planetary orbits — The Secular Variations of the Planetary Orbits (French: Variations Séculaires des Orbites Planétaires, abbreviated as VSOP) is a semi analytic theory describing the long term changes (secular variation) in the orbits of the planets Mercury to… …   Wikipedia

  • secular change — šimtmetinis kitimas statusas T sritis fizika atitikmenys: angl. secular change vok. sekuläre Änderung, f rus. вековая вариация, f; вековое изменение, n pranc. changement séculaire, m; variation séculaire, f …   Fizikos terminų žodynas

  • variation séculaire — šimtmetinis kitimas statusas T sritis fizika atitikmenys: angl. secular change vok. sekuläre Änderung, f rus. вековая вариация, f; вековое изменение, n pranc. changement séculaire, m; variation séculaire, f …   Fizikos terminų žodynas

  • Solar variation — Solar variations are changes in the amount of solar radiation emitted by the Sun. There are periodic components to these variations, the principal one being the 11 year solar cycle (or sunspot cycle), as well as aperiodic fluctuations. Solar… …   Wikipedia

  • geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… …   Universalium

  • Earth's magnetic field — Computer simulation of the Earth s field in a normal period between reversals.[1] The tubes represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and… …   Wikipedia

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