biology

Mesovortex

Mesovortex is a biology 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 Mesovortex rather than just read about it. In short: A mesovortex is a small-scale rotational feature found in a convective storm, such as a quasi-linear convective system (QLCS), a supercell, or the eyewall of a tropical cyclone. Mesovortices range in diameter from tens of miles to a mile or less and can be immensely intense.

Key takeaways

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

Reference excerpt

A mesovortex is a small-scale rotational feature found in a convective storm, such as a quasi-linear convective system (QLCS), a supercell, or the eyewall of a tropical cyclone. Mesovortices range in diameter from tens of miles to a mile or less and can be immensely intense.

Eyewall mesovortex

An eyewall mesovortex is a small-scale rotational feature found in an eyewall of an intense tropical cyclone. Eyewall mesovortices are similar, in principle, to small "suction vortices" often observed in multiple-vortex tornadoes. In these vortices, wind speed can be up to 10% higher than in the rest of the eyewall. Eyewall mesovortices are most common during periods of intensification in tropical cyclones. Eyewall mesovortices often exhibit unusual behavior in tropical cyclones. They usually revolve around the low pressure center, but sometimes they remain stationary. Eyewall mesovortices have even been documented to cross the eye of a storm. These phenomena have been documented observationally, experimentally, and theoretically. Eyewall mesovortices are a significant factor in the formation of tornadoes after tropical cyclone landfall. Mesovortices can spawn rotation in individual thunderstorms (a mesocyclone), which leads to tornadic activity. At landfall, friction is generated between the circulation of the tropical cyclone and land. This can allow the mesovortices to descend to the surface, causing large outbreaks of tornadoes. On 15 September 1989, during observations for Hurricane Hugo, Hunter NOAA42 accidentally flew through an eyewall mesovortex measuring 320 km/h (200 mph) and experienced crippling G-forces of +5.8Gs and -3.7Gs. The winds ripped off the propeller de-icing boot and pushed the flight down to a perilous 1,000 ft (300 m) above sea level. The ruggedized Lockheed WP-3D Orion was only designed for a maximum of +3.5Gs and −1G.

Mesocyclone

A mesocyclone is a type of mesovortex, approximately 1 to 10 km (0.6 to 6 mi) in diameter (the mesoscale of meteorology), within a convective storm. Mesocyclones are air that rises and rotates around a vertical axis, usually in the same direction as low pressure systems in a given hemisphere. They are most often associated with a localized low-pressure region within a severe thunderstorm. Mesocyclones are believed to form when strong changes of wind speed and/or direction with height ("wind shear") sets parts of the lower part of the atmosphere spinning in invisible tube-like rolls. The convective updraft of a thunderstorm is then thought to draw up this spinning air, tilting the air's axis of rotation upward (from parallel to the ground to perpendicular) and causing the entire updraft to rotate as a vertical column. Mesocyclones are normally relatively localized: they lie between the synoptic scale (hundreds of kilometers) and small scale (hundreds of meters). Radar imagery is used to identify these features.

Mesoscale convective vortex

A mesoscale convective vortex (MCV) is a low-pressure center (mesolow) within a mesoscale convective system (MCS) that pulls winds into a circling pattern, or vortex. With a core only 30 to 60 mi (48 to 97 km) wide and 1 to 3 mi (1.6 to 4.8 km) deep, an MCV is often overlooked in standard surface observations. They have most often been detected on radar and satellite, particularly with the higher resolution and sensitivity of WSR-88D, but with the advent of mesonets, these mesoscale features can also be detected in surface analysis. An MCV can persist for more than 12 hours after its parent MCS has dissipated. This orphaned MCV will sometimes then become the seed of the next thunderstorm outbreak. Their remnants will often lead to an "agitated area" of increased cumulus activity that can eventually become an area of thunderstorm formation. Associated low-level boundaries left behind can themselves cause convergence and vorticity that can increase the level of organization and intensity of any storms that do form. An MCV that moves into tropical waters, such as the Gulf of Mexico, can serve as the nucleus for a tropical cyclone (as in the case of Hurricane Barry in 2019, for instance). MCVs, like mesovortices, often cause an intensification of convective downburst winds and can lead to tornadogenesis. One form of MCV is the "comma head" of a line echo wave pattern (LEWP).

Example of May 2009 Mid-Mississippi Valley MCV

On Friday, May 8, 2009, a major MCV controversially dubbed an "inland hurricane" by local media moved through southern Missouri, southern Illinois, western Kentucky, and southwestern Indiana, killing at least six and injuring dozens more. Damage estimates were in the hundreds of millions. Top speeds of 106 mph (171 km/h) were reported in Carbondale, Illinois.

See also Convective storm detection Wake low Derecho Mesoscale convective complex (MCC) Rear-inflow jet (RIJ) Bow echo

References

External links A National Weather Service case study on linear mesovortices NOAA Glossary Houze, R.A. Jr. (2004). "Mesoscale convective systems". Rev. Geophys. 42 (4): RG4003. Bibcode:2004RvGeo..42.4003H. doi:10.1029/2004RG000150. S2CID 53409251.

Illustrations

Worked examples

Example 1 — a first encounter with Mesovortex

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

In research: Mesovortex appears in biology 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 Mesovortex 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: Mesovortex is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mesoscale meteorology, Radar meteorology, Severe weather and convection, so understanding it makes those chapters shorter.
In everyday life: Look for Mesovortex 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 Mesovortex in 20 minutes

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

Frequently asked questions

What is Mesovortex in simple terms?

Why does Mesovortex matter?

Because it connects several biology 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 Mesovortex?

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 Mesovortex.