annual variation


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Related to annual variation: seasonal variation

annual variation

[′an·yə·wəl ver·ē′ā·shən]
(astronomy)
The change in the right ascension and declination of a star during one year, due to the combined effect of the star's proper motion and the precession of the equinoxes.
(geophysics)
A component in the change with time in the earth's magnetic field at a specified location that has a period of 1 year.

annual variation

The quantum of yearly change in variation at a place. This is normally indicated on the bottom of a map or chart and must be added/subtracted to/from the figure given on the map after taking into consideration the number of years elapsed since the last survey for the map. Variation is the angular difference between the direction of true north and magnetic north at any given point.
References in periodicals archive ?
Figure 3d shows the annual variation for Chechon, representing the erosivity variation in Region IV in the inland mountainous area of South Korea.
When data from all years at Prairie Creek were compared, significant annual variation was present for the big brown bat ([[chi].sup.2] = 10.627, p = 0.031), little brown myotis ([[chi].sup.2] = 12.612, p = 0.013), northern myotis ([[chi].sup.2] = 10.351,p = 0.035), and Indiana myotis ([[chi].sup.2] = 18.687, p = 0.001).
This provides justification for focusing only on this fraction of the autumn-winter period to document patterns of annual variation in the interactions of birds and fruits.
Annual variation of litter size and offspring size in a viviparous skink.
Semi-annual variations were found to be approximately an order of magnitude smaller than annual variations. Results for the semi-annual variations yielded to inconsistent results both in scale and phase shift, as the notably larger mass content of the annual frequency overwhelms the runoff characteristics.
The annual variation rates of the temperature and precipitation were calculated using the annual mean temperature and precipitation of each pixel for China and different regions during 1998-2013 (Figures 4 and 5).
The interaction sex*bi-month was significant (F [.sub.5/263] = 4.87; p < 0.001), the annual variation of body mass was highly different between sexes (Fig.
2001), but have not described the annual variation in diet or food resources.
Up to September 2011, the average inflation rate, measured by annual variation in the Consumer Price Index (CPI), stood higher at 4.2 per cent compared to three per cent a year ago.
The fact that the highest observed population rate was [approximately equal to] 50% greater than the lowest rate suggests that annual variation in norovirus activity may account for a considerable proportion of what otherwise seems to be unspecified.
Another potential mechanism that could account for annual variation in size of litters is residual effects of reproduction in prior years (Lourdais et al., 2002).
Gareth Jones, ASCL secretary, said he had been "receiving a stream of comment about the huge annual variation in 16-19 funding allocated to LEAs and subsequently schools".

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