The Pacific–North American teleconnection pattern (PNA) is a
climatological
Climatology (from Greek , ''klima'', "place, zone"; and , ''-logia'') or climate science is the scientific study of Earth's climate, typically defined as weather conditions averaged over a period of at least 30 years. This modern field of study ...
term for a large-scale weather pattern with two modes, denoted positive and negative, and which relates the
atmospheric
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
circulation pattern over the North
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
with the one over the
North American continent.
The positive phase of the PNA pattern features above-average
barometric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibar ...
heights in the vicinity of
Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only ...
and over the inter-mountain region of
North America, and below-average heights located south of the
Aleutian Islands
The Aleutian Islands ( ; ; ale, Unangam Tanangin, "land of the Aleuts"; possibly from the Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before 1867, the Catherine Archipelago—are a chain of 14 main, ...
and over the southeastern United States. The PNA pattern is associated with strong fluctuations in the strength and location of the East Asian
jet stream. The positive phase is associated with an enhanced East Asian jet stream and with an eastward shift in the jet exit region toward the western United States. The negative phase is associated with a westward retraction of that jet stream toward eastern Asia, blocking activity over the high latitudes of the North Pacific, and a strong split-flow configuration over the central North Pacific.
The positive phase of the PNA pattern is associated with above-average temperatures over western
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...
and the extreme western United States, and below-average temperatures across the south-central and southeastern US. The PNA tends to have little impact on surface temperature variability over North America during summer. The associated precipitation anomalies include above-average totals in the
Gulf of Alaska
The Gulf of Alaska (Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the eas ...
extending into the Pacific Northwestern United States, and below-average totals over the upper Midwestern United States.
The negative PNA phase is associated with the opposite.
Although the PNA pattern is a natural internal mode of climate variability, it is also strongly influenced by the
El Niño-Southern Oscillation
EL, El or el may refer to:
Religion
* El (deity), a Semitic word for "God"
People
* EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer
* El DeBarge, music artist
* El Franco Lee (1949–2016), American ...
(ENSO) phenomenon. The positive phase of the PNA pattern tends to be associated with Pacific warm episodes (El Niño), and the negative phase tends to be associated with Pacific cold episodes (La Niña).
See also
*
Teleconnection
Teleconnection in atmospheric science refers to climate anomalies being related to each other at large distances (typically thousands of kilometers). The most emblematic teleconnection is that linking sea-level pressure at Tahiti and Darwin, Austr ...
*
Arctic dipole anomaly
The Arctic dipole anomaly is a pressure pattern characterized by high pressure on the arctic regions of North America and low pressure on those of Eurasia. This pattern sometimes replaces the Arctic oscillation and the North Atlantic oscillatio ...
*
Arctic oscillation
The Arctic oscillation (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM) is a weather phenomenon at the Arctic pole north of 20 degrees latitude. It is an important mode of climate variability for the Northern Hemisphere. The s ...
*
El Niño-Southern Oscillation
EL, El or el may refer to:
Religion
* El (deity), a Semitic word for "God"
People
* EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer
* El DeBarge, music artist
* El Franco Lee (1949–2016), American ...
*
European windstorm
European windstorms are powerful extratropical cyclones which form as cyclonic windstorms associated with areas of low atmospheric pressure. They can occur throughout the year, but are most frequent between October and March, with peak inten ...
*
Global storm activity of 2010
The global weather activity of 2010 includes major meteorological events in the Earth's atmosphere during the year, including winter storms (blizzards, ice storms, European windstorms), hailstorms, out of season monsoon rain storms, extratropic ...
*
Kuroshio Current
The , also known as the Black or or the is a north-flowing, warm ocean current on the west side of the North Pacific Ocean basin. It was named for the deep blue appearance of its waters. Similar to the Gulf Stream in the North Atlantic, the Ku ...
*
North Atlantic oscillation
The North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in th ...
*
North Pacific Gyre
The North Pacific Gyre (NPG) or North Pacific Subtropical Gyre (NPSG), located in the northern Pacific Ocean, is one of the five major oceanic gyres. This gyre covers most of the northern Pacific Ocean. It is the largest ecosystem on Earth, locat ...
*
Pacific Decadal Oscillation
The Pacific decadal oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20°N. O ...
*
Pineapple Express
Pineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent large-scale flow of warm moist air, and the associated heavy precipitation both in the waters immediately northeast of the Hawaii ...
*
Walker circulation
The Walker circulation, also known as the Walker cell, is a conceptual model of the air flow in the tropics in the lower atmosphere (troposphere). According to this model, parcels of air follow a closed circulation in the zonal and vertical dir ...
*
Madden–Julian oscillation
The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30- to 90-day) variability in the tropical atmosphere. It was discovered in 1971 by Roland Madden and Paul Julian of the American National Center for Atmospheric ...
References
*
*Barnston, A. G., and R. E. Livezey, 1987: Classification, seasonality and persistence of low-frequency atmospheric circulation patterns. Mon. Wea. Rev., 115, 1083-1126.
Regional climate effects
Physical oceanography
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