A Stüve diagram is one of four

thermodynamic diagrams Thermodynamic diagrams are diagrams used to represent the thermodynamic states of a material (typically fluid) and the consequences of manipulating this material. For instance, a temperature–entropy diagram ( T–s diagram) may be used to demon ...

commonly used in weather analysis and forecasting. It was developed circa 1927 by the German meteorologist Georg Stüve (1888–1935) and quickly gained widespread acceptance in the United States to plot

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

and

dew point The dew point is the temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content. When cooled below the dew point, moisture capacity is reduced and airborne water vapor will cond ...

data from

radiosonde A radiosonde is a battery-powered telemetry instrument carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Modern radiosondes measure or calcula ...

s. 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 e ...

and

potential temperature The potential temperature of a parcel of fluid at pressure P is the temperature that the parcel would attain if adiabatically brought to a standard reference pressure P_, usually . The potential temperature is denoted \theta and, for a gas well-a ...

. The isotherms are straight and vertical, isobars are straight and horizontal, dry adiabats are also straight and have a 45° inclination to the left, while moist adiabats are curved. 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, named after Rudolf Clausius and Benoît Paul Émile Clapeyron, specifies the temperature dependence of pressure, most importantly vapor pressure, at a discontinuous phase transition between two phases of matter ...

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 ( Green 1992). It is formulated as the integral of air density along the lig ...

, it thus does not permit calculation of the

Convective Available Potential Energy In meteorology, convective available potential energy (commonly abbreviated as CAPE), is the integrated amount of work that the upward (positive) buoyancy force would perform on a given mass of air (called an air parcel) if it rose vertically thr ...

(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 a ...

tephigram A tephigram is one of four 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 plot. Usuall ...

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