TY - JOUR
T1 - Strong Linkage of El Niño–Southern Oscillation to the Polar Cold Air Mass in the Northern Hemisphere
AU - Abdillah, Muhammad Rais
AU - Kanno, Yuki
AU - Iwasaki, Toshiki
N1 - Funding Information:
This study is partly supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) through Grant-in-Aid 15H02129 and the Program on Climate Change Adaptation Technology (SI-CAT). M. R. A. is grateful to MEXT for the scholarship support. Y. K. is supported by a Grant-in-Aid for Research Fellows (16J01722) of the JSPS. We are grateful to the constructive comments from two anonymous reviewers and the Editor. The JRA-55 reanalysis data set is available at Japan Meteorological Agency (JMA) Data Distribution System (http://jra.kishou. go.jp/JRA-55/index_en.html). The Niño-3.4 and AO indices are obtained from NOAA (https://www.esrl.noaa.gov/psd/ data).The codes for analysis and plot used in this paper are publicly available at http://doi.org/10.5281/ zenodo.1246402.
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/6/16
Y1 - 2018/6/16
N2 - The total hemispheric polar cold air mass (PCAM) amount below a threshold potential temperature is conserved under an adiabatic condition and is a good indicator of polar warming. While the long-term PCAM trends have been investigated, the cause of its interannual variability remains uncertain. Here we find that the El Niño–Southern Oscillation has a strong impact on the total northern hemispheric PCAM amount below a potential temperature of 280 K. The correlation coefficient between the Niño-3.4 and the total PCAM reaches −0.66 over 36 recent winters. During El Niño, the PCAM decreases significantly because of the shorter PCAM residence time at high latitudes. The Aleutian Low intensifies and effectively transfers the PCAM from North America to the North Pacific, causing a significant decrease in the PCAM amount over the northern part of North America and a strengthening of cold air outflows over the central North Pacific. The PCAM coming to the warm ocean disappears rapidly and results in the imbalance of the hemispheric PCAM. This study reveals a notable influence of the tropical forcing on the variability of polar climate.
AB - The total hemispheric polar cold air mass (PCAM) amount below a threshold potential temperature is conserved under an adiabatic condition and is a good indicator of polar warming. While the long-term PCAM trends have been investigated, the cause of its interannual variability remains uncertain. Here we find that the El Niño–Southern Oscillation has a strong impact on the total northern hemispheric PCAM amount below a potential temperature of 280 K. The correlation coefficient between the Niño-3.4 and the total PCAM reaches −0.66 over 36 recent winters. During El Niño, the PCAM decreases significantly because of the shorter PCAM residence time at high latitudes. The Aleutian Low intensifies and effectively transfers the PCAM from North America to the North Pacific, causing a significant decrease in the PCAM amount over the northern part of North America and a strengthening of cold air outflows over the central North Pacific. The PCAM coming to the warm ocean disappears rapidly and results in the imbalance of the hemispheric PCAM. This study reveals a notable influence of the tropical forcing on the variability of polar climate.
KW - El Niño–Southern Oscillation
KW - polar cold air mass
KW - teleconnection
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U2 - 10.1029/2018GL077612
DO - 10.1029/2018GL077612
M3 - Article
AN - SCOPUS:85048968454
VL - 45
SP - 5643
EP - 5652
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 11
ER -
