scholarly journals Influence of Asian-Pacific Oscillation on Precipitation in Central Eastern China during Autumn (1960–2016)

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Zouxing Lin ◽  
Jiajin Zhu ◽  
Wei Hua ◽  
Guangzhou Fan
Keyword(s):  
Close Association ◽  
Eastern China ◽  
Walker Circulation ◽  
Reanalysis Data ◽  
Teleconnection Pattern ◽  
Upward Movement ◽  
Tropical Eastern Pacific ◽  
The Pacific ◽  
Central Eastern ◽  
Asian Pacific

The Asian-Pacific Oscillation (APO) plays an important role in precipitation in Central Eastern China (CEC). This study analyzed observational and reanalysis data to investigate CEC precipitation during autumn (1960–2016) and its association with the APO. The APO index (APOI) was redefined, and an autumn CEC precipitation index (CECPI) was calculated to elucidate the relationship between the APO and CEC precipitation. Significant positive correlation (correlation coefficient: 0.60) was found between the APOI and CECPI. Further analysis revealed anomalous southerly winds at 850 hPa over CEC when the APO was strong, which corresponded to anomalous strengthened (weakened) sea level pressure and increased 500-hPa geopotential height over Asia (the Pacific), together with strong meridional shear of the East Asian jet. This configuration is conducive to transportation of warm moist air to CEC during strong APOI years (SAY), but the effect is much diminished during weak APOI years. Moreover, strengthening of both the Walker Circulation of the tropical Pacific and the anomalous upward movement (and convergence) over the Western Pacific (WP) observed during SAY is also conducive to the formation of precipitation in CEC. A possible physical explanation for the close association of the APO with tropical circulation changes is that decreased (increased) sea surface temperature in the tropical eastern Pacific (WP and extratropical Pacific) is beneficial for stimulating a strong APO teleconnection pattern, which further affects precipitation in CEC by strengthening the connection between tropical and subtropical regions.

scholarly journals Influence of Decadal Ocean Signals on Meteorological Conditions Associated With the Winter Haze Over Eastern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Wen Zhang ◽  
Xiao Dong ◽  
Zhenxin Liu ◽  
Renping Lin ◽  
Hao Luo
Keyword(s):  
Time Scale ◽  
Wave Train ◽  
Eastern China ◽  
Meteorological Conditions ◽  
Positive Phase ◽  
Decadal Time Scale ◽  
Near Surface ◽  
The Pacific ◽  
Decadal Scale ◽  
Central Eastern

The possible influence of the Atlantic multidecadal oscillation (AMO) and the Pacific decadal oscillation (PDO) on the meteorological conditions associated with haze over central eastern China at decadal time scale was investigated using reanalysis and observational dataset for 1979–2018. Four indices, including Siberian high (SH) strength and position indices (SHI/SHPI), a normalized near-surface wind-speed index (WSI) and a potential air temperature gradient index (ATGI), are adopted to denote the meteorological conditions associated with haze. Results shown that the AMO and PDO are both highly correlated with the fluctuation of meteorological factors associated with haze on decadal scale. Although AMO and PDO were in opposite phases during the whole period, since 1997, they both changed phases (AMO shifted to a positive phase and PDO changed to negative) and became favorable for an anomalous dipole-type SLP pattern in the middle-high latitudes of East Asia. The AMO has played a leading role in decadal variation of the large-scale circulation system, while the PDO has had a closer relationship with the lower ventilation condition in eastern China. On the decadal time scale, the AMO stimulates a zonal teleconnection wave train (the AMO northern Hemisphere pattern, ANH) that originates from the North Atlantic Ocean and passes through central Europe, the northern Ural Mountains, Lake Balkhash-Baikal, and central eastern China. During the positive phase of AMO, the ANH induces a stronger and westward shifted SH, with the central eastern China controlled by the anomalous high pressure. In addition, affected by the cyclone (anticyclone) anomaly over Hetao region and North China (the Sea of Japan), southerly wind anomalies dominate over central eastern China. Compared with the AMO, the wave train generated by the negative (positive) PDO phase mainly propagates in the Pacific region, and there is a strong anticyclonic (cyclonic) anomaly over the Northeast Pacific, guiding the air flow southward (northward) along the East Asian coast and thus suppressing (encouraging) the dispersion of pollutants and resulting in above (below)-normal haze episodes.

Atmospheric teleconnection patterns associated with severe and mild ice cover on the Great Lakes, 1963–2011

2012 ◽  
Vol 47 (3-4) ◽  
pp. 421-435 ◽  
Author(s):  
Xuezhi Bai ◽  
Jia Wang
Keyword(s):  
North America ◽  
Great Lakes ◽  
El Niño ◽  
El Nino ◽  
Ice Cover ◽  
Reanalysis Data ◽  
Teleconnection Pattern ◽  
La Niña ◽  
Atmospheric Teleconnection ◽  
La Nina

Atmospheric teleconnection circulation patterns associated with severe and mild ice cover over the Great Lakes are investigated using the composite analysis of lake ice data and National Center of Environmental Prediction (NCEP) reanalysis data for the period 1963–2011. The teleconnection pattern associated with the severe ice cover is the combination of a negative North Atlantic Oscillation (NAO) or Arctic Oscillation (AO) and negative phase of Pacific/North America (PNA) pattern, while the pattern associated with the mild ice cover is the combination of a positive PNA (or an El Niño) and a positive phase of the NAO/AO. These two extreme ice conditions are associated with the North American ridge–trough variations. The intensified ridge–trough system produces a strong northwest-to-southeast tilted ridge and trough and increases the anomalous northwesterly wind, advecting cold, dry Arctic air to the Great Lakes. The weakened ridge–trough system produces a flattened ridge and trough, and promotes a climatological westerly wind, advecting warm, dry air from western North America to the Great Lakes. Although ice cover for all the individual lakes responds roughly linearly and symmetrically to both phases of the NAO/AO, and roughly nonlinearly and asymmetrically to El Niño and La Niña events, the overall ice cover response to individual NAO/AO or Niño3.4 index is not statistically significant. The combined NAO/AO and Niño3.4 indices can be used to reliably project severe ice cover during the simultaneous –NAO/AO and La Niña events, and mild ice cover during the simultaneous +NAO/AO and El Niño events.

Vietnam in the Indo-Pacific Region: Perception, Position and Perspectives

2021 ◽  
pp. 097492842110050
Author(s):  
Nguyen Le Thy Thuong ◽  
Nguyen Thi Oanh
Keyword(s):  
Swot Analysis ◽  
Geographic Area ◽  
Common Interest ◽  
Pacific Region ◽  
Analysis Model ◽  
Common Space ◽  
The Pacific ◽  
The World ◽  
State Behaviour ◽  
Asian Pacific

The Indo-Pacific region is an area adjacent to some oceans and the gateway that connects the great power and small countries to the world; this region is always considered by Vietnam as a key strategic geographic area, having direct impacts on national security, position and its role in this region. While big powers have different perceptions to the Indo-Pacific region, as a country occupying an important geographic position in the Pacific region, Vietnam shares a common vision of an open and rule-based area, and a common interest in maintaining peace, stability and prosperity as well as building a common space for coexistence and development with the belief that the Indo-Asian-Pacific is large enough for every nation to grow and prosper. This article finds out that recent changes in the Indo-Pacific region in geopolitics, economics, security and national defence have made many countries, including Vietnam, to redefine their global and regional policies to refresh their strategic perceptions. Vietnam has its own perception, position, approach and national orientations, which is shaping its state behaviour and perspectives in this geopolitical vibrant Indo-Pacific region. Besides, this article uses the SWOT analysis model to determine the challenges, strengths and weaknesses of Vietnam in the Indo-Pacific region. Moreover, while the future of the Indo-Pacific in a post-COVID-19 pandemic world remains filled with uncertainty and economic challenges, the crisis also presents an opportunity for Vietnam to re-evaluate its position. Today, Vietnam always maintains its foreign policy of independence, self-reliance, multilateralism and diversification of international relations, which attaches great importance to enhancing multi-faceted cooperation with countries in the Indo-Pacific region. Thus, with its own perception and geostrategic advantage, Vietnam—a developing country in the region and in the world with relatively stable economic growth, pursuing rules and order will be a positive factor for a stable, peaceful and prosperous development in the region.

Characterization of aerosol acidity at a high mountain site in central eastern China

2012 ◽  
Vol 51 ◽  
pp. 11-20 ◽  
Author(s):  
Yang Zhou ◽  
Likun Xue ◽  
Tao Wang ◽  
Xiaomei Gao ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Eastern China ◽  
High Mountain ◽  
Aerosol Acidity ◽  
Mountain Site ◽  
Central Eastern
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