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Cold surge pathways in east Asia and their tropical impacts
Abdillah M.R.a, Kanno Y.b, Iwasaki T.c, Matsumoto J.d,e
a Atmospheric Science Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia
b Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Tokyo, Japan
c Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan
d Department of Geography, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Hachioji, Japan
e Dynamic Coupling of Ocean-Atmosphere-Land Research Program, Japan Agency for Marine Earth Science and Technology, Yokosuka, Japan
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).Cold surge occurrences are one of the robust features of winter monsoon in East Asia and are characterized by equatorward outbreaks of cold air from the high latitudes. Beside greatly affecting weather variability across the Far East, cold surges are of importance for Southeast Asian countries because they can propagate far to the tropics and excite convective activities. However, the tropical responses highly depend on the downstream pathways of the surges. To better understand how cold surges influence tropical weather, we investigate 160 cold surges identified using a quantitative approach during 40 winters from 1979/80 to 2018/19, and then classify them into several groups based on their prominent pathways. At the midlatitudes, we find two groups: one for surges that show clear equatorward propagation of cold air to lower latitudes and the other for surges that turn eastward and bring cold air to the North Pacific. These groups arise due to the strength difference of the Siberian high expansion controlled by cold air blocking near the Tibetan Plateau. The tropical impact is evident in the former group. We perform further classification on this group and find four types of surges based on their pathways in the low latitudes: 1) South China Sea (SCS) surges, 2) Philippines Sea (PHS) surges, 3) both SCS and PHS surges, and 4) blocked surges. They exhibit distinct precipitation signatures over the Maritime Continent, which are driven by interactions between the surges and the pre-existing synoptic conditions over the tropics, particularly the Madden-Julian oscillation (MJO).[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Convective activity,Madden-Julian oscillation,Maritime Continent,Quantitative approach,Strength differences,Synoptic conditions,Tropical response,Weather variability[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Cold air surges,Intraseasonal variability,Maritime Continent,Precipitation,Synoptic climatology[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]Acknowledgments. The authors thank two anonymous reviewers for their constructive comments and suggestions. This research is supported by the Japan Society for the Promotion of Science (JSPS) through a Grand-in-Aid 15H02129. MRA is thankful to Tohoku University for inviting him to work on this topic in early 2020. MRA is partly supported by P3MI-ITB (ITB Research, Community Service, and Innovation Program). YK is partly supported by JSPS KAKENHI Grants 18H03738, 20H05167, and 20H01976. JM is partly supported by JSPS KAKENHI Grants 17H061160 and 20H01386, and Tokyo Metropolitan Government Advanced Research Grant H28-2. The JRA-55 reanalysis is available at Japan Meteorological Agency (JMA) Data Distribution System (http://jra.kishou.go.jp/ JRA-55/index_en.html). The interpolated OLR and SST data provided by the NOAA/OAR/ESRL PSL, Boulder, Colorado, USA, from their Web site at https://psl.noaa.gov/. The PERSIANN-CDR precipitation data are obtained from NOAA Climate Data Record at http://doi.org/10.7289/ V51V5BWQ. The codes for analysis and plot used in this paper are publicly available at http://doi.org/10.5281/ zenodo.3945990.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1175/JCLI-D-20-0552.1[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]