secular variation


Also found in: Wikipedia.

secular variation

[′sek·yə·lər ‚ver·ē′ā·shən]
(astronomy)
A perturbation of the moon's motion caused by variations in the effect of the sun's gravitational attraction on the earth and moon as their relative distances from the sun vary during the synodic month.
(geophysics)
The changes, measured in hundreds of years, in the magnetic field of the earth. Also known as geomagnetic secular variation.
References in periodicals archive ?
2011, Polynomial Modelling of Southern African Secular Variation Observations Since 2005.
Brief reminder of the "solar system astrometric anomalies" will be in order here: (a) Anomalous secular increase of the eccentricity of the orbit of the moon [3-7] (b) the fly-by-anomaly [8-10] (c) precession of Saturn [11-12], (d) secular variation of the gravitational-parameter GM (i.
Two cases are considered: constant dietary cholesterol (at the granularity of observation) and secular variation in dietary habits.
Geomagnetic Secular Variation in the Canary Islands: paleomagnetic data, models and application to paleomagnetic dating
They include recurrence quantification analysis of bipolar disorder performed using a Van der Pol oscillator model, detecting low-dimensional chaos in small noisy sample sets, Alan Turing meets the Sphinx, fractal geometry in computer graphics and in virtual reality, buyer decisions in the US housing industry, secular variation in the climatic memory of five Italian deep lakes, and in everyday action notes for a mindscape of bioethics.
Although small in comparison with the main dipole field, secular variation can be difficult to predict with effects substantial enough to prompt a revision of the International Geomagnetic Reference Field every five years.
1997 Pictorial remanent magnetization as an indicator of secular variation of the Earth's magnetic field.
Due to proudly aloof tone, composite effect isn't as satisfying as a good bank heist or other secular variation on cops and robbers.
A theme that pervaded the discussion concerned secular variation of orogenic processes.
In addition to the outbreak surveillance reports, the preliminary reports of isolates are consistent with minimal changes in the occurrence of SE infection in 1989 and 1990; this pattern could reflect either secular variation in the epidemic or the possible effects of control measures.
The core-spot movement toward thepoles, he says, shows that "the old notion of westward drift as an explanation of secular variation [changes in the magnetic field over time] is on the way out and may be replaced with something more like the sunspot descriptions used for the solar field.
There has been a dramatic increase in the number of archaeomagnetic studies in Iberia during the last two decades, which has enabled the proposal of a first reference secular variation curve for the region (Gomez-Paccard et al.