physics

Tephigram

Tephigram is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tephigram rather than just read about it. In short: A tephigram is one of several thermodynamic diagrams commonly used in weather analysis and forecasting. The name evolved from the original name "T- ϕ {\displaystyle \phi } -gram" to describe the axes of temperature (T) and entropy ( ϕ {\displaystyle \phi } ) used to create the plot.

Key takeaways

Tephigram belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tephigram to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tephigram from memory before moving on to harder problems.

Reference excerpt

A tephigram is one of several thermodynamic diagrams commonly used in weather analysis and forecasting. The name evolved from the original name "T- ϕ {\displaystyle \phi } -gram" to describe the axes of temperature (T) and entropy ( ϕ {\displaystyle \phi } ) used to create the plot. Usually, temperature and dew point data from radiosondes 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.

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 adiabats 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.

See also Thermodynamic diagrams Stüve diagram

Notes

References

Bibliography M.H.P. Ambaum, Thermal Physics of the Atmosphere, published by Wiley-Blackwell, April 16, 2010, 240 pages. ISBN 978-0-470-74515-1 R.R. Rogers and M.K. Yau, Short Course in Cloud Physics, Third Edition, published by Butterworth-Heinemann, January 1, 1989, 304 pages. ISBN 9780750632157 ISBN 0-7506-3215-1 J.V. Iribarne and W.L. Godson, Atmospheric Thermodynamics, 2nd Edition, published by D. Reidel Publishing Company, Dordrecht, Netherlands, 1981, 278 pages, ISBN 90-277-1297-2, ISBN 978-90-277-1296-7

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

Illustrations

Worked examples

Example 1 — a first encounter with Tephigram

Start with the simplest possible case. Write down what Tephigram claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tephigram before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tephigram ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tephigram

In research: Tephigram appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tephigram in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tephigram is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atmospheric science stubs, Atmospheric thermodynamics, so understanding it makes those chapters shorter.
In everyday life: Look for Tephigram outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tephigram in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tephigram means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tephigram out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tephigram in simple terms?

Why does Tephigram matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tephigram?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tephigram.