earth science

Western Hemisphere Warm Pool

Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool rather than just read about it. In short: The Western Hemisphere Warm Pool (WHWP) is a region of sea surface temperatures (SST) warmer than 28.5 °C that develops west of Central America in the spring, then expands to the tropical waters to the east. The WHWP includes the tropical Atlantic Ocean (TNA) east of the Lesser Antilles, Caribbean Sea, Gulf of Mexico, and eastern north Pacific Ocean (ENP).

Key takeaways

Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Western Hemisphere Warm Pool from memory before moving on to harder problems.

Reference excerpt

The Western Hemisphere Warm Pool (WHWP) is a region of sea surface temperatures (SST) warmer than 28.5 °C that develops west of Central America in the spring, then expands to the tropical waters to the east. The WHWP includes the tropical Atlantic Ocean (TNA) east of the Lesser Antilles, Caribbean Sea, Gulf of Mexico, and eastern north Pacific Ocean (ENP). A WHWP heating cycle begins with warmth in the eastern North Pacific in the spring. A dipole pattern off Central America appears due to surges of cooler, drier air through the gap at the Isthmus of Tehuantepec. During spring, the warm pools grow and merge. Their warmth and moisture feed the Mexican monsoon. By summer, the warmth spreads across the Gulf of Mexico and Caribbean areas.

Relationship with Atlantic hurricanes Recent studies have shown that the Atlantic portion of the WHWP (AWP) is significantly correlated with Atlantic hurricane activity. A large (or small) AWP reduces (or increases) the tropospheric vertical wind shear in the main development region for Atlantic hurricanes and increases (or decreases) the moist static instability of the troposphere, both of which favor (or do not favor) the intensification of tropical storms into major hurricanes.

Relationship with El Niño A study of climate records has shown a relationship between El Niño and the Western Hemisphere Warm Pool (WHWP). During a normal Northern Hemisphere winter, diabatic heating over the Amazon drives a Hadley cell with descending air over an anticyclone north of 20°N in the subtropical North Atlantic and associated northeast trade winds between Africa and the Caribbean. An El Niño weakens the Amazonian cell, the anticyclone and the easterly tradewinds, causing the tropical North Atlantic to warm more than usual in the spring. About half of El Niño events persist sufficiently into the spring months for the warm pool to become unusually large by summer.

Climate events in area 800–900: Collapse of Classical Maya civilization due to drought. Yucatán Peninsula in present-day Mexico.

References

Wang, C., S.-K. Lee and D. B. Enfield, 2008: Atlantic warm pool acting as a link between Atlantic multidecadal oscillation and Atlantic tropical cyclone activity. Geochem. Geophys. Geosyst., 9, Q05V03, doi:10.1029/2007GC001809. (In the special issue of "Interactions between climate and tropical cyclones on all timescales") Wang, C., S.-K. Lee and D.B. Enfield, 2008: Climate response to anomalously large and small Atlantic warm pools during the summer. Journal of Climate, Vol. 21, No. 11, 2437–2450. Wang, C., S.-K. Lee and D.B. Enfield, 2007: Impact of the Atlantic warm pool on the summer climate of the western hemisphere . Journal of Climate, Vol. 20, No. 20, 5021-5040. Lee, S.-K., D.B. Enfield and C. Wang, 2007: What drives seasonal onset and decay of the Western Hemisphere Warm Pool?. Journal of Climate, Vol. 20, No. 10, 2133-2146. Wang, C. and S.-K. Lee, 2007: Atlantic warm pool, Caribbean low-level jet, and their potential impact on Atlantic hurricanes. Geophysical Research Letter, Vol. 34, No. L02703, doi:10.1029/2006GL028579. Wang, C., D.B. Enfield, S.-K. Lee and C.W. Landsea, 2006: Influences of Atlantic Warm Pool on western hemisphere summer rainfall and Atlantic Hurricanes. Journal of Climate, Vol. 19, No. 12, 3011-3028. Enfield, D.B. and S.-K. Lee, 2005: The Heat Balance of the Western Hemisphere Warm Pool. Journal of Climate, Vol. 18, No. 14, 2662-2681. Enfield, D.B., S.-K. Lee, and C. Wang, 2005: How are large Western Hemisphere Warm Pools formed?. Progress in Oceanography. Wang, C., 2005: ENSO, Atlantic climate variability, and the Walker and Hadley circulations. In The Hadley Circulation: Present, Past, and Future, H. F. Diaz and R. S. Bradley, Eds., Kluwer Academic Publisher: 173-202. Lee, S.-K., D.B. Enfield, and C. Wang, 2003: Ocean general circulation model sensitivity experiments on the annual cycle of Western Hemisphere Warm Pool. Journal of Geophysical Research 110: C09004, doi=10.1029/2004JC002640. doi:10.1029/2004JC002640. Wang, C. and D.B. Enfield, 2003: A Further Study of the Tropical Western Hemisphere Warm Pool. Journal of Climate 16 (16): 1476-1493. Wang, C. and D.B. Enfield, 2001: The tropical Western Hemisphere warm pool. Geophys. Res. Lett. 28: 1635-1638. doi:10.1029/2000GL011763.

External links Central American coral records

Illustrations

Worked examples

Example 1 — a first encounter with Western Hemisphere Warm Pool

Start with the simplest possible case. Write down what Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool

In research: Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool 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: Western Hemisphere Warm Pool is common in secondary-school and first-year university syllabi. It links to neighbouring topics Natural history of Central America, Natural history of the Americas, Natural history of the Caribbean, so understanding it makes those chapters shorter.
In everyday life: Look for Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool in 20 minutes

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

Frequently asked questions

What is Western Hemisphere Warm Pool in simple terms?

Why does Western Hemisphere Warm Pool 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 Western Hemisphere Warm Pool?

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 Western Hemisphere Warm Pool.