column density

column density

The number of atoms (of a particular element or ion) per unit area, often used to measure the amount of absorption caused by intervening matter along a line of sight.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
References in periodicals archive ?
Amendments might include increasing floor thickness, increasing column density, using vibration-isolating MEP components or isolating a part of the slab from the remainder of the building.
Here, we inferred annual mean ambient ground-level N[O.sub.2] concentrations worldwide from 1996 to 2012 using observations of N[O.sub.2] tropospheric column density from three satellite instruments together with a chemical transport model.
The NH3 column density ranged from 1.3x1014-1.5x1016 cm-1 with larger densities offset from the peak integrated emission the two clumps.
Specifically, the hydrogen column density can be found using
Based upon the proven three column density gradient, the new Ray-Ran system consists of three glass tubes housed in a perspex water jacket.
Buyers of commercial property, particularly buyers of Manhattan trophy office buildings, generally don't question 25% full floor Loss Factors notwithstanding the fact that Manhattan office buildings come in all shapes and sizes with vastly different floor plate configurations, load bearing column density, width of perimeter HVAC convectors, etc.
In women who are more than five years beyond menopause, calcitonin slows bone loss, increases spinal column density, and reduces the risk of spinal fractures.
* Column density: Column grids determine the flexibility of the space.
Sykes and his colleagues from the University of Arizona's Steward Observatory and from the Planetary Science Institute, both in Tucson, "the atmosphere is thinner than originally thought.' In fact, Sykes adds, the atmospheric column density on Pluto can be at best no more than about one nine-hundredth of earth's.
The first--the new Ray-Ran Advanced Auto Density Measurement System, which is based upon the proven 3 Column Density Gradient method--accurately measures the position of the sample and float by means of an encoder which is linked to the microprocessor that automatically calculates the density of the sample.