Exploring the combined effects of the Arctic Oscillation and ENSO on the wintertime climate over East Asia using self‐organizing maps

2017 ◽  
Vol 122 (17) ◽  
pp. 9107-9129 ◽  
Author(s):  
Wenyu Huang ◽  
Ruyan Chen ◽  
Zifan Yang ◽  
Bin Wang ◽  
Wenqian Ma
Keyword(s):  
East Asia ◽  
Arctic Oscillation ◽  
The Arctic ◽  
Combined Effects ◽  
Self Organizing Maps ◽  
The Arctic Oscillation ◽  
Self Organizing

scholarly journals Self-Organizing Maps of Atmospheric Circulation and Interannual Variability of Hydrometeorological Fields in the Arctic

2020 ◽  
Author(s):  
E. E. Lemeshko ◽  
Keyword(s):  
Interannual Variability ◽  
Atmospheric Circulation ◽  
Atmospheric Pressure ◽  
Arctic Oscillation ◽  
Sea Surface ◽  
The Arctic ◽  
Self Organizing Maps ◽  
Arctic Oscillation Index ◽  
The Arctic Oscillation ◽  
Self Organizing

The article suggests the use of a nonlinear method of data analysis based on a neural network – an algorithm of Kohonen self-organizing maps for the task of typing the atmospheric surface circulation in the Arctic. Based on the construction of self-organizing surface pressure maps, the seasonal and interannual variability of atmospheric circulation in the Arctic for the period 1979–2018 is studied. Several modes were distinguished: cyclonic, two anticyclonic, and three mixed types. Indices of seasonal and annual repeatability of self-organizing atmospheric pressure maps are introduced, which allow us to study the temporal variability of atmospheric circulation modes and a composite method is proposed for calculating connected maps of other hydrometeorological parameters. The regimes of variability of the area of sea ice distribution and sea surface temperature depending on the type of atmospheric circulation are highlighted. Depending on the type of wind regime, there is a change in the area of sea ice distribution due to the variability of the flows of warm Atlantic waters into the Arctic Ocean. The characteristic types of sea surface temperature variability in the Barents Sea are identified, which are modulated by cyclonic / anticyclonic regimes of atmospheric circulation in the region and are an indicator of heat advection by the Atlantic waters. The interrelation is established of the repeatability index of self-organizing atmospheric pressure maps characterizing the types of atmospheric circulation with the variability of the Arctic Oscillation Index. The revealed regularities of the change in the types of cyclonic-anticyclonic atmospheric circulation are manifested in the interannual variability of the introduced repeatability index of selforganizing atmospheric pressure maps, which is a development of the Arctic Oscillation Index, improves understanding of the atmospheric climate circulation regimes in the Arctic.

scholarly journals Relationship between the Arctic Oscillation and Cold Surges over East Asia

2011 ◽  
Vol 24 (1) ◽  
pp. 68-83 ◽  
Author(s):  
Tae-Won Park ◽  
Chang-Hoi Ho ◽  
Song Yang
Keyword(s):  
East Asia ◽  
Arctic Oscillation ◽  
Wave Train ◽  
The Arctic ◽  
Aleutian Low ◽  
Cold Surge ◽  
Dipole Structure ◽  
Cold Surges ◽  
The Arctic Oscillation ◽  
Blocking Type

Abstract The present study reveals the changes in the characteristics of cold surges over East Asia associated with the Arctic Oscillation (AO). Based on circulation features, cold surges are grouped into two general types: wave train and blocking types. The blocking type of cold surge tends to occur during negative AO periods, that is, the AO-related polarity of the blocking type. However, the wave train type is observed during both positive and negative AO periods, although the wave train features associated with negative AO are relatively weaker. The cold surges during negative AO are stronger than those during positive AO in terms of both amplitude and duration. The cold surges during positive AO in which the extent of effect is confined to inland China passes through East Asia quickly because of weaker Siberian high and Aleutian low, leading to short duration of these cold surges. In contrast, the cold surge during negative AO, characterized by a well-organized anticyclone–cyclone couplet with high pressure over continental East Asia and low pressure over Japan, brings continuous cold air into the entire East Asian region for more than one week with long-lasting cold advection. It is also found that the tracks of the cold surges during negative AO tend to occur more frequently over Korea and Japan and less frequently over China, compared with those during positive AO. The tracks are related to a west–east dipole structure of the ratio of rain conversion to snow according to AO phase, resulting in freezing precipitation or snowfall events over inland China (Korea and Japan) are likely to occur more frequently during the positive (negative) AO periods.

scholarly journals Frequency Associations between East Asian Jet Streams and the Temperature over the Barents–Kara Sea Region/Arctic Oscillation in Winter

Climate ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 107
Author(s):  
Yuefeng Li ◽  
Yuxiang Zhu ◽  
Wei Song
Keyword(s):  
East Asia ◽  
Arctic Oscillation ◽  
East Asian ◽  
Kara Sea ◽  
Wavelet Coherence ◽  
The Arctic ◽  
Jet Stream ◽  
Jet Streams ◽  
The Arctic Oscillation ◽  
Cross Wavelet

The frequency associations between jet streams over East Asia and the Arctic key temperature at 2 m (AKT2m) in the Barents–Kara Sea region (40°–75° E, 66°–82° N) and the Arctic Oscillation in winter are investigated using continuous wavelet transform, cross-wavelet transform, and wavelet coherence. The cross-wavelet transforms between the AKT2m/Arctic Oscillation and the East Asian polar front jet stream (EAPJ) suggest that the EAPJ is closely related to the AKT2m and Arctic Oscillation on an interannual (3–5-year band) timescale, but the variation in the phase angle denotes a complex frequency connection between the EAPJ and Arctic Oscillation. The squared wavelet coherence suggests that weakening of the EAPJ is associated with the rise in AKT2m during the period of abrupt climate change in East Asia. The EAPJ contains more forced components from the Arctic than the East Asian subtropical jet stream. By comparison, the relationship between AKT2m and the EAPJ is closer than that between the Arctic Oscillation and EAPJ, especially during the period of abrupt climate change in East Asia. This suggests that the EAPJ serves as a bridge for Arctic warming to affect the weather and climate over East Asia in winter. By contrast, the Arctic Oscillation does not play an important part, although it also contains information about the Arctic.

scholarly journals Combined Effects of the MJO and the Arctic Oscillation on the Intraseasonal Eastern China Winter Temperature Variations

2019 ◽  
Vol 32 (8) ◽  
pp. 2295-2311 ◽  
Author(s):  
Lei Song ◽  
Renguang Wu
Keyword(s):  
East Asia ◽  
High Latitude ◽  
Western Europe ◽  
Arctic Oscillation ◽  
Wave Train ◽  
Eastern China ◽  
The Arctic ◽  
Wave Source ◽  
Temperature Anomalies ◽  
The Arctic Oscillation

AbstractThe present study reveals that the Madden–Julian oscillation (MJO)-related temperature anomalies over East Asia have notable differences among positive, neutral, and negative Arctic Oscillation (AO) phases. In MJO phases 2–3, cold anomalies over eastern China occur mainly during positive AO. In MJO phase 7, warm anomalies over eastern China are observed mostly during neutral AO, and in MJO phase 8 warm anomalies appear in positive and neutral AO. Regional mean temperature anomalies over northeastern East Asia tend to be negative during negative AO but positive during positive AO in six of eight MJO phases. In MJO phases 2–3, the AO-related mid- to high-latitude wave train over Eurasia and the MJO convection-triggered poleward wave train work together in contributing to negative height anomalies over eastern China and leading to cold anomalies there. The mid- to high-latitude wave train is stronger when the AO is negative than positive, which is associated with stronger zonal winds. In MJO phases 7–8, the positive AO-related mid- to high-latitude wave train over Eurasia and the MJO-induced poleward wave train cooperate in inducing positive height anomalies and leading to warm anomalies over eastern China. The mid- to high-latitude wave train is the main contributor to negative height anomalies over eastern China when the AO is negative during MJO phases 7–8. Meanwhile, the intensity of the South Asian wave source associated with the MJO convection is subjected to the modulation of southeastward dispersion of wave energy from western Europe during negative AO.

scholarly journals Combined Effects of the North Atlantic Oscillation and the Arctic Oscillation on Sea Surface Temperature in the Alborán Sea

PLoS ONE ◽  
2013 ◽  
Vol 8 (4) ◽  
pp. e62201 ◽  
Author(s):  
José C. Báez ◽  
Luis Gimeno ◽  
Moncho Gómez-Gesteira ◽  
Francisco Ferri-Yáñez ◽  
Raimundo Real
Keyword(s):  
Surface Temperature ◽  
North Atlantic ◽  
Arctic Oscillation ◽  
Sea Surface ◽  
The Arctic ◽  
Combined Effects ◽  
The North ◽  
The North Atlantic ◽  
The Arctic Oscillation ◽  
The North Atlantic Oscillation

scholarly journals Beryllium-7 and Lead-210 are Associated with an Increase in the Arctic Oscillation: Evidence from Atmospheric Aerosols in a Remote Tropical Region in East Asia

2021 ◽  
Author(s):  
Xiaoxia Chen ◽  
Wuhui Lin ◽  
Xianwen He ◽  
Liangliang Feng ◽  
Kuo-Ying Wang
Keyword(s):  
East Asia ◽  
High Latitude ◽  
Arctic Oscillation ◽  
Meteorological Data ◽  
Large Fraction ◽  
The Arctic ◽  
Tropical Region ◽  
Monitoring Site ◽  
High Latitudes ◽  
The Arctic Oscillation

AbstractThe Arctic Oscillation (AO) accounts for a large fraction of recent decadal climate trends in Northern Hemisphere (NH) high latitudes. In East Asia, an elevated AO index (AOI) was associated with warmer temperatures in middle- to high-latitude regions, colder temperatures over low-latitude regions, and elevated ozone intrusion from the stratosphere. Elevated beryllium-7 (7Be) is produced in the stratosphere. Few studies have discussed the relationship between 7Be and the AO. Here, we identify the AO signature in 7Be and lead (Pb)-210 observed at a tropical ambient monitoring site in Nanning (22.8°N, 108.5°E) during the December 2014–December 2017 period. Our results show that the 7Be and 210Pb concentrations are positively and significantly correlated with the AOI (P < 0.01). These results show that elevated 7Be and 210Pb are associated with an increase in the AOI, reflecting air masses originating from NH high latitudes and vertically from the high-latitude upper troposphere and lower stratosphere regions to tropical latitudes in East Asia. These results have been verified with ozonesonde data without seasonality and with two meteorological data sets. Our results are also confirmed by observational data over the Pacific regions. We conclude that the AO exerts impacts over the tropical regions in East Asia, and 7Be can be used as a tracer to track the impacts of the AO.

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