earth science

Pulse storm

Pulse storm is a earth science 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 Pulse storm rather than just read about it. In short: A pulse storm is a single cell thunderstorm of substantial intensity which only produces severe weather for short periods of time. Such a storm weakens and then generates another short burst – hence "pulse".

Key takeaways

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

Reference excerpt

A pulse storm is a single cell thunderstorm of substantial intensity which only produces severe weather for short periods of time. Such a storm weakens and then generates another short burst – hence "pulse". The term was coined by researchers at the National Severe Storms Laboratory in 1979 to describe a single storm cell briefly becoming severe within a cluster of multi-cellular thunderstorms, but has since been used to describe a variety of isolated and brief thunderstorms with both severe and non-severe characteristics.

Description Single cell thunderstorms ordinarily form in environments with low wind shear and moderate instability, with the low wind shear contributing to a short average lifespan of less than an hour. When the instability, calculated by convective available potential energy (CAPE), is strong, the updraft will bring a larger amount of humid air very high above ground and generate a cumulonimbus cloud with high water and ice content. When the rain content, and even hail, falls from it, they can generate damaging winds brought about by downbursts. Rarely, a weak tornado develops in association with a pulse storm as the environment is only weakly sheared, or not at all.

Life cycle

One can distinguish three stages in the evolution of a pulse storm:

Formation: the upward current of the cell intensifies and allows the condensation of water vapor from the rising air parcel. This forms a cumulus congestus or a towering cumulus, then a cumulonimbus when ice crystals form at its apex which spreads horizontally in contact with the tropopause. Maturity: downdrafts are emerging. This stage is accompanied by characteristic phenomena such as lightning and thunder, showers, and gust front. Dissipation: the cold pool descending from the cloud extends to the Earth's surface and helps to block the feed by pushing the updraft downstream. The outflow can then serve as a trigger for other single cell or even multi-cell thunderstorms to develop because the Outflow boundary is a lifting mechanism for updrafts because it can force more warm humid air into the atmosphere.

Worked examples

Example 1 — a first encounter with Pulse storm

Start with the simplest possible case. Write down what Pulse storm claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, 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 Pulse storm 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 Pulse storm 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 Pulse storm

In research: Pulse storm appears in earth science 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 Pulse storm 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: Pulse storm is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atmospheric science stubs, Severe weather and convection, so understanding it makes those chapters shorter.
In everyday life: Look for Pulse storm 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 Pulse storm in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pulse storm 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 Pulse storm out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pulse storm in simple terms?

Why does Pulse storm matter?

Because it connects several earth science 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 Pulse storm?

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 Pulse storm.