Cold Air Mass Analysis of the Record-Breaking Cold Surge Event over East Asia in January 2016

AbstractThe paths of winter cold surge (CS) events in East Asia (EA) from 1979 to 2017 are tracked by the Flexible Particle (FLEXPART) model using ERA-Interim daily datasets, and the probability density distribution of the paths is calculated by the kernel density estimation (KDE) method. The results showed that the paths of CSs are significantly correlated with the intensity of the CSs, which shows an interdecadal transition from weak to strong around 1995. CS paths can be classified into two types, namely, the western path type and the northern path type, which were more likely to occur before and after 1995, respectively. Before 1995, the cold air mainly originated from Europe and moved from west to east, and the synoptic features were associated with the zonal wave train. After 1995, cold air accumulated over western Siberia and then invaded EA along the northern path, and the synoptic features were mainly associated with the blocking structure. The geopotential height (GPH) anomalies over the Arctic were abnormally strong. This paper further analyzes the relationship between CSs and winter sea ice concentration (SIC) in the Arctic. The results show that the intensity of CSs is negatively correlated with the Barents SIC (BSIC). When the BSIC declines, the upward wave flux over the Barents Sea is enhanced and expanded to the midlatitude region. GPH anomalies over the Arctic are positive and form a negative AO-like pattern, which is conducive to the formation of the northern path CS. Furthermore, the observed results are supported by numerical experiments with the NCAR Community Atmosphere Model, version 5.3 (CAM5.3).

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Cold Surge Pathways in East Asia and Their Tropical Impacts

Journal of Climate ◽

10.1175/jcli-d-20-0552.1 ◽

2021 ◽

Vol 34 (1) ◽

pp. 157-170

Author(s):

Muhammad Rais Abdillah ◽

Yuki Kanno ◽

Toshiki Iwasaki ◽

Jun Matsumoto

Keyword(s):

East Asia ◽

Far East ◽

The Tibetan Plateau ◽

Cold Surge ◽

Cold Air ◽

The North ◽

Synoptic Conditions ◽

Cold Surges ◽

Tropical Weather ◽

The Tropics

AbstractCold 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).

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An Isentropic Analysis of the Temporal Evolution of East Asian Cold Air Outbreaks

Journal of Climate ◽

10.1175/jcli-d-14-00307.1 ◽

2014 ◽

Vol 27 (24) ◽

pp. 9337-9348 ◽

Cited By ~ 34

Author(s):

Takamichi Shoji ◽

Yuki Kanno ◽

Toshiki Iwasaki ◽

Koutarou Takaya

Keyword(s):

East Asia ◽

Temporal Evolution ◽

East Asian ◽

Potential Temperature ◽

Aleutian Low ◽

Air Mass ◽

Cold Air ◽

Siberian High ◽

Synoptic Conditions ◽

Cold Air Outbreaks

Abstract The equatorward cold airmass flux below potential temperature θT = 280 K across 45°N integrated from 90°E to 180° is used as an index to quantitatively measure cold air outbreaks (CAOs) in the East Asian winter monsoon. Intermittent CAOs over East Asia significantly contribute to the global equatorward cold airmass flux. An autocorrelation analysis indicates that CAO events persist for approximately 5 days. The geographical distributions of lagged correlations/regressions with the CAO index (CAOI) clarify the temporal evolution of synoptic conditions associated with CAOs. The developing Siberian high located northwest of Lake Baikal (65°N, 100°E) on day −4 slowly moves southeastward, reaches maximum intensity over Siberia (50°N, 110°E) on day 0, and then decays while moving rapidly southward. By contrast, the Aleutian low is almost stagnant and maintains a strong intensity. The eastward pressure gradient geostrophically induces the equatorward cold airmass flux. After day −2, the cold air mass significantly decreases over Siberia, but increases over East Asia and the western North Pacific Ocean. The cold air mass continues to migrate southward while spreading eastward, and disappears mainly over the ocean. The leading edge of the high pressure anomaly moves southward at 13 m s−1 and reaches the equator simultaneously with the equatorward wind anomaly on about day +4. An additional analysis of separating the equatorward flux into 90°–135°E and 135°E–180° suggests that CAOs are, to some extent, caused by the Siberian high and the Aleutian low acting separately.

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A Synergistic Effect of Blockings on a Persistent Strong Cold Surge in East Asia in January 2018

Atmosphere ◽

10.3390/atmos11020215 ◽

2020 ◽

Vol 11 (2) ◽

pp. 215 ◽

Cited By ~ 1

Author(s):

Wei Dong ◽

Liang Zhao ◽

Shunwu Zhou ◽

Xinyong Shen

Keyword(s):

Synergistic Effect ◽

East Asia ◽

Air Temperature ◽

Western Europe ◽

The Arctic ◽

West Siberian Plain ◽

Near Surface ◽

Cold Surge ◽

Cold Air ◽

The Pacific

A persistent strong cold surge occurred in East Asia in late January 2018, causing mean near-surface air temperature in China to hit the second lowest since 1984. Moreover, the daily mean air temperature remained persistently negative for more than 20 days. Here, we find that a synergistic effect of double blockings in Western Europe and North America plays an important accelerating role in the rapid phase transition of Arctic Oscillation and an amplifying role in the strength of cold air preceding to the cold surge outbreaks by the use of an isentropic potential vorticity analysis. In mid-January, an Atlantic mid-latitude anticyclone merged with Western Europe blocking, which led to a strengthening of the blocking. Simultaneously, the Pacific-North American blocking was also significantly strengthened. The two blockings synchronously deeply stretched towards the Arctic, which resulted in, on the one hand, warm and moist air of the Pacific and the Atlantic being excessively transported into the Arctic, and on the other hand, the polar vortex being split and cold air being squeezed southwards and accumulating extensively on the West Siberian Plain. After the breakdown of the double blocking pattern, which lasted for about 10 days, the record-breaking cold surge broke out in East Asia. It was discovered that the synergistic effect of double blockings extending into the Arctic, which is conducive to extreme cold events, has been rapidly increasing in recent years.

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Dampak Seruak Dingin Monsun Dingin Asia Terhadap Variabilitas Hujan Di Jawa

Prosiding SNFA (Seminar Nasional Fisika dan Aplikasinya) ◽

10.20961/prosidingsnfa.v5i0.46614 ◽

2020 ◽

Vol 5 ◽

Author(s):

Taryono Taryono ◽

Fatkhuroyan Fatkhuroyan

Keyword(s):

Tibetan Plateau ◽

South China Sea ◽

Central Asia ◽

South China ◽

Cold Surge ◽

Air Mass ◽

Cold Air ◽

Wind Analysis ◽

Mass Flows ◽

The Impact

Abstract: Cold surge is a cold air mass flows from Central Asia near Tibetan Plateau through south china sea into western part of Indonesia. The aim of the paper is to investigate the cold surge impacts to rainfall in Java. It clasify the cold surge based on to the strength by calculating data of wind surface from ECMWF ERA-Interim for 30 years. Then a composite rainfall and wind analysis was carried out on the impact of cold surge. The analysis shows that weak cold surge had impact on the decrease of about 15% of rainfall in Java which associated with Borneo Vortex. While the strong cold surge had an impact on the increase of about 43% of rainfall in Java.Abstrak: Seruak Dingin (Cold surge) merupakan aliran masa udara dingin yang berasal dari daratan Asia sekitar Tibet melalui Laut Cina Selatan hingga ke wilayah Indonesia bagian barat saat monsoon Asia musim dingin. Tujuan penelitian ialah untuk mengkaji dampak seruak dingin terhadap curah hujan di wilayah Jawa. Metode yang dipakai ialah dengan mengklasifikasikan seruak dingin berdasarkan kekuatannya dengan memperhitungkan data angin permukaan ECMWF ERA_Interim selama 30 tahun sejak 1980-2010. Lalu dilakukan analisi komposit curah hujan dan angin terhadap dampak seruak dingin. Hasil analisa menunjukan saat seruak dingin lemah terjadi penurunan curah hujan sebesar 15% yang berhubungan dengan borneo vortex. Sedangkan saat seruak dingin kuat, berdampak pada kenaikan sekitar 43% curah hujan di Jawa.

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