TY - JOUR
T1 - Revisiting the impact of mid-latitude cold air outbreaks on the Maritime Continent weather
AU - Abdillah, M. R.
AU - Iwasaki, T.
N1 - Funding Information:
We thank Dr. Y. Kanno for providing a tool for isentropic calculations and constructive comments. 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).
Publisher Copyright:
© 2019 IOP Publishing Ltd. All rights reserved.
PY - 2019/8/2
Y1 - 2019/8/2
N2 - The East Asian winter exhibits frequent cold air outbreaks (CAOs), or cold surges, which often cause severe cold waves in the extratropics. CAOs are also of importance for forecasters in the Maritime Continent because the associated equatorward outflows can influence tropical weather. Various CAO definitions have been documented, but a definition based on a quantitative approach was only recently proposed. Studies of the CAO impact often linked a surge index in the subtropics instead of an index in the midlatitude where CAOs basically occur. Here, we investigate the impact by using a quantitative CAO index, which is defined by integrating cold air mass flux below a threshold potential temperature over midlatitude East Asia (45°N, 90°-135°E). From a climatological analysis, tropical convections are significantly observed two-to-four days following CAO event (i.e., the peak of CAO index), indicating CAO impacts. However, case studies show that the impacts vary among independent CAO cases due to influences of associated synoptic conditions, which affect the pathways of northerlies propagation and consequently hinder or amplify the impacts. Several impact patterns and their possible causes are discussed. A better understanding of East Asian CAO variability can improve the predictability of weather over the Maritime Continent.
AB - The East Asian winter exhibits frequent cold air outbreaks (CAOs), or cold surges, which often cause severe cold waves in the extratropics. CAOs are also of importance for forecasters in the Maritime Continent because the associated equatorward outflows can influence tropical weather. Various CAO definitions have been documented, but a definition based on a quantitative approach was only recently proposed. Studies of the CAO impact often linked a surge index in the subtropics instead of an index in the midlatitude where CAOs basically occur. Here, we investigate the impact by using a quantitative CAO index, which is defined by integrating cold air mass flux below a threshold potential temperature over midlatitude East Asia (45°N, 90°-135°E). From a climatological analysis, tropical convections are significantly observed two-to-four days following CAO event (i.e., the peak of CAO index), indicating CAO impacts. However, case studies show that the impacts vary among independent CAO cases due to influences of associated synoptic conditions, which affect the pathways of northerlies propagation and consequently hinder or amplify the impacts. Several impact patterns and their possible causes are discussed. A better understanding of East Asian CAO variability can improve the predictability of weather over the Maritime Continent.
KW - cold air outbreaks
KW - maritime continent
KW - weather
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U2 - 10.1088/1755-1315/303/1/012062
DO - 10.1088/1755-1315/303/1/012062
M3 - Conference article
AN - SCOPUS:85070593953
VL - 303
JO - IOP Conference Series: Earth and Environmental Science
JF - IOP Conference Series: Earth and Environmental Science
SN - 1755-1307
IS - 1
M1 - 012062
T2 - 1st International Conference on Tropical Meteorology and Atmospheric Science, ICTMAS 2018
Y2 - 19 September 2018 through 20 September 2018
ER -