Abstract
The two types of El Niño that have been identified, namely the eastern Pacific (EP) and central Pacific (CP) El Niños, are known to exert different climatic impacts on the North Atlantic region during winter. Here, we investigate the characteristics of the teleconnection of the two El Niño types with a focus on the stratosphere-troposphere coupling. During the EP El Niño, polar stratospheric warming and polar vortex weakening frequently occur with a strong tendency for downward propagation near the tropopause. Consequently, the atmospheric pattern within the troposphere over the North Atlantic sector during midwinter closely resembles the negative North Atlantic Oscillation pattern. In contrast, during CP El Niño events stratospheric warming events exhibit a much weaker downward propagation tendency. This difference in the stratospheric circulation response arises from the different seasonal evolution of the tropospheric wave response to the two El Niño types. For the EP El Niño, the Aleutian Low begins growing during December and is sustained throughout the entire winter (December to February), which provides favorable conditions for the continuous downward propagation of the stratospheric warming. We also discuss the origin of the difference in the teleconnections from the two types of El Niño associated with the distinct longitudinal position of the warm SST anomaly that determines troposphere-stratosphere coupling.
| Original language | English |
|---|---|
| Pages (from-to) | 159-170 |
| Number of pages | 12 |
| Journal | Climate Dynamics |
| Volume | 42 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 2014 Jan 1 |
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All Science Journal Classification (ASJC) codes
- Atmospheric Science
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Altered atmospheric responses to eastern Pacific and central Pacific El Niños over the North Atlantic region due to stratospheric interference. / Sung, Mi Kyung; Kim, Baek Min; An, Soon-Il.
In: Climate Dynamics, Vol. 42, No. 1-2, 01.01.2014, p. 159-170.Research output: Contribution to journal › Article
TY - JOUR
T1 - Altered atmospheric responses to eastern Pacific and central Pacific El Niños over the North Atlantic region due to stratospheric interference
AU - Sung, Mi Kyung
AU - Kim, Baek Min
AU - An, Soon-Il
PY - 2014/1/1
Y1 - 2014/1/1
N2 - The two types of El Niño that have been identified, namely the eastern Pacific (EP) and central Pacific (CP) El Niños, are known to exert different climatic impacts on the North Atlantic region during winter. Here, we investigate the characteristics of the teleconnection of the two El Niño types with a focus on the stratosphere-troposphere coupling. During the EP El Niño, polar stratospheric warming and polar vortex weakening frequently occur with a strong tendency for downward propagation near the tropopause. Consequently, the atmospheric pattern within the troposphere over the North Atlantic sector during midwinter closely resembles the negative North Atlantic Oscillation pattern. In contrast, during CP El Niño events stratospheric warming events exhibit a much weaker downward propagation tendency. This difference in the stratospheric circulation response arises from the different seasonal evolution of the tropospheric wave response to the two El Niño types. For the EP El Niño, the Aleutian Low begins growing during December and is sustained throughout the entire winter (December to February), which provides favorable conditions for the continuous downward propagation of the stratospheric warming. We also discuss the origin of the difference in the teleconnections from the two types of El Niño associated with the distinct longitudinal position of the warm SST anomaly that determines troposphere-stratosphere coupling.
AB - The two types of El Niño that have been identified, namely the eastern Pacific (EP) and central Pacific (CP) El Niños, are known to exert different climatic impacts on the North Atlantic region during winter. Here, we investigate the characteristics of the teleconnection of the two El Niño types with a focus on the stratosphere-troposphere coupling. During the EP El Niño, polar stratospheric warming and polar vortex weakening frequently occur with a strong tendency for downward propagation near the tropopause. Consequently, the atmospheric pattern within the troposphere over the North Atlantic sector during midwinter closely resembles the negative North Atlantic Oscillation pattern. In contrast, during CP El Niño events stratospheric warming events exhibit a much weaker downward propagation tendency. This difference in the stratospheric circulation response arises from the different seasonal evolution of the tropospheric wave response to the two El Niño types. For the EP El Niño, the Aleutian Low begins growing during December and is sustained throughout the entire winter (December to February), which provides favorable conditions for the continuous downward propagation of the stratospheric warming. We also discuss the origin of the difference in the teleconnections from the two types of El Niño associated with the distinct longitudinal position of the warm SST anomaly that determines troposphere-stratosphere coupling.
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U2 - 10.1007/s00382-012-1661-0
DO - 10.1007/s00382-012-1661-0
M3 - Article
VL - 42
SP - 159
EP - 170
JO - Climate Dynamics
JF - Climate Dynamics
SN - 0930-7575
IS - 1-2
ER -