2. Parameters

Temperature/Levels » Thickness Definition

Definition: Thickness

Thickness refers to the vertical distance between two constant pressure surfaces (isobars).

The thickness of a layer is related to the mean virtual temperature (Tv) according to the formula:

Equation used to define thickness

Where:

  • ΔZ = thickness (m)
  • Rd = gas constant for dry air
  • Symbol for mean virtual temperature = mean virtual temperature for the layer
  • p1 = pressure at the bottom of the layer
  • p2 = pressure at the top of the layer
  • g = gravitational acceleration

Note for a given pair of pressures, the thickness is proportional to the mean virtual temperature (Tv) in the layer. The 1000-500 hPa thickness is perhaps the most commonly used because it corresponds to the mean temperature in the lower half of the troposphere. It is typically plotted on weather charts with 60-meter contours. In this case, each contour reflects a mean virtual temperature change of about 3°C.