A Stüve diagram is one type of thermodynamic diagram commonly used in weather analysis and forecasting. This diagram has a simplicity in that it uses straight lines for the three primary variables:

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

and potential temperature. The isotherms are straight and vertical (acting as the x-axis) while isobars are straight and horizontal (acting as the y-axis). Dry adiabats are straight and solid green but are tilted while moist adiabats do not have the same slope throughout and are dashed and cyan. Wind barbs, symbols used to show wind speed and direction, are often plotted at the side of the diagram to indicate the winds at different heights. However, using this configuration sacrifices the equal-area property of the original

Clausius–Clapeyron relation The Clausius–Clapeyron relation, in chemical thermodynamics, specifies the temperature dependence of pressure, most importantly vapor pressure, at a discontinuous phase transition between two phases of matter of a single constituent. It is nam ...

requirements between the temperature of the environment and the temperature of a parcel of air lifted/lowered. Although it permits analysis of the cloud cover and the stability of the

airmass In astronomy, air mass or airmass is a measure of the amount of air along the line of sight when observing a star or other celestial source from below Earth's atmosphere . It is formulated as the integral of air density along the light ray. As i ...

, it thus does not permit calculation of the Convective Available Potential Energy (CAPE). This is why the three other thermodynamic diagrams (

emagram An emagram is one of four thermodynamic diagrams used to display temperature lapse rate and moisture content profiles in the atmosphere. The emagram has axes of temperature (T) and pressure (p). In the emagram, the dry adiabats make an angle of ab ...

tephigram A tephigram is one of a number of thermodynamic diagrams commonly used in weather analysis and forecasting. The name evolved from the original name "T-\phi-gram" to describe the axes of temperature (T) and entropy (\phi) used to create the plo ...

s, and

skew-T log-P diagram A skew-T log-P diagram is one of four thermodynamic diagrams commonly used in weather analysis and forecasting. In 1947, N. Herlofson proposed a modification to the emagram that allows straight, horizontal isobars and provides for a large angle ...

s) are most often preferred, the latter in the USA nowadays.

References

* * Atmospheric thermodynamics {{climate-stub

See also

References