Pacific-North American teleconnection pattern
Encyclopedia
The Pacific-North American teleconnection pattern (PNA) is a climatological
term for 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 America
n continent.
The positive phase of the PNA pattern features above-average barometric pressure heights in the vicinity of Hawaii
and over the intermountain region of North America
, and below-average heights located south of the Aleutian Islands 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
and the extreme western United States, and below-average temperatures across the south-central and southeastern U.S. 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
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
(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).
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
term for a large-scale weather pattern with two modes, denoted positive and negative, and which relates the atmospheric
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
circulation pattern over the North Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
with the one over the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n continent.
The positive phase of the PNA pattern features above-average barometric pressure heights in the vicinity of Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and over the intermountain region of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, and below-average heights located south of the Aleutian Islands and over the southeastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. 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
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
and the extreme western United States, and below-average temperatures across the south-central and southeastern U.S. 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
Gulf of Alaska
The Gulf of Alaska 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 east, where Glacier Bay and the Inside Passage are found.The entire shoreline of the Gulf is...
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 Niño-Southern Oscillation
El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...
(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
- TeleconnectionTeleconnectionTeleconnection in atmospheric science refers to climate anomalies being related to each other at large distances...
- Arctic dipole anomalyArctic dipole anomalyThe Arctic dipole anomaly is a pressure pattern characterized by high pressure on the arctic regions of North America, and a low pressure on the Eurasia region. This pattern sometimes replaces the Arctic oscillation and the North Atlantic Oscillation. It was observed for the first time in the...
- Arctic oscillationArctic oscillationThe Arctic oscillation or Northern Annular Mode/Northern Hemisphere Annular Mode is an index of the dominant pattern of non-seasonal sea-level pressure variations north of 20N latitude, and it is characterized by pressure anomalies of one sign in the Arctic with the opposite anomalies centered...
- El Niño-Southern OscillationEl Niño-Southern OscillationEl Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...
- European windstormEuropean windstormA European windstorm is a severe cyclonic windstorm associated with areas of low atmospheric pressure that track across the North Atlantic towards northwestern Europe. They are most common in the winter months...
- Global storm activity of 2010Global storm activity of 2010The former article was split into three to avoid confusion between the three periods of storm activity.*Global storm activity of early 2010 – January–April 2010*Global storm activity of mid 2010 – May–September 2010...
- Kuroshio CurrentKuroshio CurrentThe Kuroshio is a north-flowing ocean current on the west side of the North Pacific Ocean. It is similar to the Gulf Stream in the North Atlantic and is part of the North Pacific ocean gyre...
- North Atlantic oscillationNorth Atlantic oscillationThe North Atlantic oscillation is a climatic phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level between the Icelandic low and the Azores high. Through east-west oscillation motions of the Icelandic low and the Azores high, it controls the...
- North Pacific GyreNorth Pacific GyreThe North Pacific Gyre, located in the northern Pacific Ocean, is one of the five major oceanic gyres. This gyre comprises most of the northern Pacific Ocean. It is the largest ecosystem on our planet...
- Pacific Decadal OscillationPacific decadal oscillationThe Pacific Decadal Oscillation is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20° N...
- Pineapple ExpressPineapple ExpressPineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent flow of atmospheric moisture and associated heavy rainfall from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America...
- Walker circulationWalker circulationThe Walker circulation, also known as the Walker cell, is a conceptual model of the air flow in the tropics in the lower atmosphere . According to this model parcels of air follow a closed circulation in the zonal and vertical directions...