Hydrostatic Equation (dry air approximation)

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Equation / Last modified by mike on 2015/07/29 08:15
MichaelBartmess.Hydrostatic Equation (dry air approximation)

Hydrostatic Equation

  The hydrostatic equation is one of the most important and most basic equations in meteorology. Understanding the equation makes it easier to physically interpret  thickness charts (which display the difference in height between two atmospheric pressure levels). Pressure at any point in the atmosphere is equal to the weight of the air column above the point.  The equation can be generalized as:

`dP/dh = - "density" * "gravity"`

So, we can compute the change in pressure at an altitudes above the Earth's surface (sea level) to be:

dp = - `rho` * g * dh, where:

  • `rho` - the air density (assumed in this case to be the density of dry air)
  • g - the gravitational constant at sea level
  • dh - the change in height