Tephigram

 ( Atmospheric Thermodynamics ) 

A tephigram is one of several thermodynamic diagrams commonly used in weather analysis and forecasting. The name evolved from the original name "T-$\backslash phi$-gram" to describe the axes of temperature (T) and entropy ($\backslash phi$) used to create the plot. Usually, temperature and dew point data from are plotted on these diagrams to allow calculations of convective stability or convective available potential energy (CAPE). Wind barbs are often plotted alongside a tephigram to indicate the winds at different heights.

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Description The tephigram was invented by Napier Shaw in 1915 and is primarily used in the United Kingdom and Canada. Other countries use similar thermodynamic diagrams for the same purpose; however, the details of their construction vary. In a tephigram, isotherms are straight and have a 45-degree inclination to the right, while isobars are horizontal and slightly curved. Dry are also straight and have a 45-degree inclination to the left, while moist adiabats are curved.

The main reason the British Met Office, the Meteorological Service of Canada, and Met Éireann (Irish Meteorological Service) use tephigram is that the areas contained by the curves have equal energies for equal areas. This property enables better comparisons of CAPE and, hence, better assessments of convective systems.

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See also

• Thermodynamic diagrams
• Stüve diagram

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Notes

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Bibliography

• M.H.P. Ambaum, Thermal Physics of the Atmosphere, published by Wiley-Blackwell, April 16, 2010, 240 pages.
• R.R. Rogers and M.K. Yau, Short Course in Cloud Physics, Third Edition, published by Butterworth-Heinemann, January 1, 1989, 304 pages.
• J.V. Iribarne and W.L. Godson, Atmospheric Thermodynamics, 2nd Edition, published by D. Reidel Publishing Company, Dordrecht, Netherlands, 1981, 278 pages, ,

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External links

• Department of Meteorology, University of Reading page about tephigrams including pdfs of blank printable colour and monochrome tephigrams.

Categories: Atmospheric Thermodynamics

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