earth science

Pacific–North American teleconnection pattern

Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern rather than just read about it. In short: The Pacific–North American teleconnection pattern (PNA) is a large-scale weather pattern with two modes, denoted positive and negative, and which relates the atmospheric circulation pattern over the North Pacific Ocean with the one over the North American continent. It is the second leading mode of natural climate variability in the higher latitudes of the Northern Hemisphere (behind the Arctic Oscillation or North…

Key takeaways

Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pacific–North American teleconnection pattern from memory before moving on to harder problems.

Reference excerpt

The Pacific–North American teleconnection pattern (PNA) is a large-scale weather pattern with two modes, denoted positive and negative, and which relates the atmospheric circulation pattern over the North Pacific Ocean with the one over the North American continent. It is the second leading mode of natural climate variability in the higher latitudes of the Northern Hemisphere (behind the Arctic Oscillation or North Atlantic Oscillation) and can be diagnosed using the arrangement of anomalous geopotential heights or air pressures over the North Pacific and North America. On average, the troposphere over North America features a ridge on the western part of the continent and a trough over the eastern part of the continent. The positive phase of the PNA teleconnection is identified by anomalously low geopotential heights south of the Aleutian Islands and over Southeastern U.S. straddling high geopotential heights over the North Pacific from Hawaii to the U.S. Intermountain West. This represents an amplification of the long-term average conditions. The negative phase features the opposite pattern over the same regions, with above-average geopotential heights straddling below-average heights. This represents a damping of the long-term average conditions.

Indices The PNA is typically quantified using an index using geopotential height anomalies at the 500-hPa pressure level, with positive and negative PNA phases based on the sign of the index. Wallace and Gutzler (1981) expressed the PNA index as the average of normalized height anomalies at the four centers of action most relevant to the PNA,

PNA 4 = 1 4 ( z ∗ ( 20 ∘ N , 160 ∘ W ) − z ∗ ( 45 ∘ N , 165 ∘ W ) + z ∗ ( 55 ∘ N , 115 ∘ W ) − z ∗ ( 30 ∘ N , 85 ∘ W ) ) {\displaystyle {\text{PNA}}_{4}={\frac {1}{4}}(z^{*}(20^{\circ }{\text{N}},160^{\circ }{\text{W}})-z^{*}(45^{\circ }{\text{N}},165^{\circ }{\text{W}})+z^{*}(55^{\circ }{\text{N}},115^{\circ }{\text{W}})-z^{*}(30^{\circ }{\text{N}},85^{\circ }{\text{W}}))}

where z ∗ {\displaystyle z^{*}} describes the normalized 500-hPa height anomaly as a function of location. The subtropical center at (20°N, 160°W) can be excluded, though the difference between the resulting PNA 3 {\displaystyle {\text{PNA}}_{3}} index and the PNA 4 {\displaystyle {\text{PNA}}_{4}} index is small. Applying rotated principal component analysis to the 500-hPa geopotential height anomaly field in the Northern Hemisphere can also provide a quantification of the PNA ( PNA RPCA {\displaystyle {\text{PNA}}_{\text{RPCA}}} ), with the canonical PNA pattern emerging as the second-leading principal component. This methodology is used by the U.S. Climate Prediction Center to compute its PNA index.

Dynamics

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Pacific–North American teleconnection pattern

Start with the simplest possible case. Write down what Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern

In research: Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern 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: Pacific–North American teleconnection pattern is common in secondary-school and first-year university syllabi. It links to neighbouring topics Physical oceanography, Regional climate effects, so understanding it makes those chapters shorter.
In everyday life: Look for Pacific–North American teleconnection pattern 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Pacific–North American teleconnection pattern” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Pacific–North American teleconnection pattern in 20 minutes

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

Frequently asked questions

What is Pacific–North American teleconnection pattern in simple terms?

Why does Pacific–North American teleconnection pattern 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 Pacific–North American teleconnection pattern?

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 Pacific–North American teleconnection pattern.