Admittance (geophysics)

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In geophysics, admittance describes the small effects of atmospheric pressure on earth gravity. Studies have also been carried out regarding the gravity of Venus.[1] Admittance in geophysics takes atmospheric pressure as the input and measures small changes in the gravitational field as the output. Geophysics admittance is commonly measured in μGal/mbar. These units convert according to 1 Gal = 0.01 m/s2 and 1 bar = 100 kPa, so in SI units the measurement would be in units of;

\frac{\mathrm{m}/\mathrm{s}^2}{\mathrm{Pa}}   or   \frac{\mathrm{m}/\mathrm{s}^2}{\mathrm{N}/\mathrm{m}^2}   or   \frac{\mathrm{m}^3}{\mathrm{N}\cdot \mathrm{s}^2}   or, in primary units   \frac{\mathrm{m}^2}{\mathrm{kg}}

However, the relationship is not a straightforward one of proportionality. Rather, an admittance function is described which is time and frequency dependent in a complex way.[2]

References[edit]

  1. ^ Hoogenboom, Trudi (2004). "Admittance survey of type 1 coronae on Venus". Journal of Geophysical Research 109. doi:10.1029/2003JE002171. 
  2. ^ Abd El-Gelil, Pagiatakis, El-Rabbany, (July 2006). "Atmospheric Air Density Admittance Function for High Precision Gravity Reduction". Elements: the newsletter of the Canadian Geophysical Union 24 (2).