Role of the East Asian trough on the eastern Mediterranean temperature variability in early spring and the extreme case of 2004 warm spell

2019 ◽  
Vol 53 (3-4) ◽  
pp. 2309-2326 ◽  
Author(s):  
Deniz Bozkurt ◽  
Yasemin Ezber ◽  
Omer Lutfi Sen
Keyword(s):  
Eastern Mediterranean ◽  
East Asian ◽  
Extreme Case ◽  
Early Spring ◽  
Temperature Variability ◽  
East Asian Trough ◽  
Warm Spell

scholarly journals Intraseasonal Variation of the Strength of the East Asian Trough and Its Climatic Impacts in Boreal Winter

2016 ◽  
Vol 29 (7) ◽  
pp. 2557-2577 ◽  
Author(s):  
Lei Song ◽  
Lin Wang ◽  
Wen Chen ◽  
Yang Zhang
Keyword(s):  
East Asia ◽  
East Asian ◽  
Quantitative Description ◽  
Storm Track ◽  
Northern Eurasia ◽  
Boreal Winter ◽  
Near Surface ◽  
East Asian Trough ◽  
Climatic Impacts

Abstract The East Asian trough (EAT) is a distinct component of the boreal winter circulation whose strength corresponds to the amplitude of the Northern Hemispheric stationary waves. In this study, the mechanism and climatic impacts of the intraseasonal variations of the EAT’s strength are investigated through composite analysis and dynamical diagnostics. The significant roles played by the low-frequency Rossby wave (RW) and synoptic transient eddy (TE) are revealed. Before the peaks of strong EAT events, an upper-tropospheric RW train propagates across northern Eurasia and interacts with preexisting surface cold anomalies over central Siberia. This pattern intensifies the Siberian high and causes RW convergence toward the EAT, leading to 30% of the EAT’s amplification directly via the RW-induced feedback forcing. Meanwhile, RW weakens the background baroclinicity and reduces TE activities near the entrance region of the North Pacific storm track. The TE-induced feedback forcing leads to another 30% of the EAT’s amplification. The evolution and dynamical processes of the weak EAT events generally resemble those of the strong events with opposite signs. These results are consistent with the knowledge on the mechanism of the strong and weak EAT events regarding the role of RWs with additional quantitative description and provide new insights regarding the role of TEs. Variations of the EAT’s strength exert significant climatic impacts on East Asia and its downstream region. Near-surface air temperature is below (above) normal over East Asia during the growth and peak stages of the strong (weak) EAT events and above (below) normal over North America afterward.

Tropical air intrusions over the eastern Mediterranean and Mesopotamia: An atmospheric river case study and role of the East Asian trough

2020 ◽  
Author(s):  
Omer L. Sen ◽  
Deniz Bozkurt ◽  
Yasemin Ezber
Keyword(s):  
Eastern Mediterranean ◽  
East Asian ◽  
Late Winter ◽  
Eastern Anatolia ◽  
Discharge Data ◽  
East Asian Trough ◽  
Anatolian Plateau ◽  
Atmospheric River ◽  
Extreme Precipitation Events ◽  
The Mediterranean

<p>The high-elevation eastern Anatolian plateau, located in eastern Mediterranean basin, is cold and snowy in winter, and functions as a water tower in providing water to Mesopotamia through Euphrates and Tigris rivers. These rivers are snow-fed, as much of their discharges occurs in spring when the seasonal warming melts the snowpack. The anomalous warming over the eastern Anatolia in early March 2004 resulted in unprecedented snowmelt runoff in the Euphrates and Tigris basin together with the accompanying rainfall. This study explores an atmospheric river (AR) leading to the extreme hydrometeorological events in the headwaters regions of the Euphrates and Tigris basins in early March 2004, and its possible linkage to the strength of the East Asian trough (EAT). In the analyses, we used reanalysis data, gridded products of surface temperature and snow cover, river discharge data and satellite imagery. We employed an intensity index for the EAT and a trough displacement index for the Mediterranean trough (MedT) to explore the relationship between the strength of the EAT and the displacement of the MedT at pentad resolution. We show that there is a strong relationship between the strength of the EAT and the zonal displacements of the Mediterranean upper layer trough on the 13th pentad of the year, which corresponds to early days of March. In 2004, which appears to be an extreme year for this phenomenon, the MedT is positioned and deepened in the central Mediterranean (about10−15◦E), and extended towards central Africa during the early days of March. This synoptic pattern provided favorable conditions for the development of AR with a southwest-northeast orientation, carrying warm tropical African air towards the eastern Mediterranean and Anatolian highlands resulting in rapid melting of the snowpack as well as severe precipitation, and thus, flooding events, in the eastern Anatolia. A key finding in our analysis is that the strengthening of the EAT was instrumental to the increased amplitude of the ridge-trough system over the Euro-Mediterranean region in the early days of 2004 late winter. A further analysis is ongoing to provide a basis to analyze past individual AR events over the region, especially those associated with extreme precipitation events and snowmelt.</p>

Euro-Mediterranean climate variability in boreal winter: a potential role of the East Asian trough

2018 ◽  
Vol 52 (11) ◽  
pp. 7071-7084 ◽  
Author(s):  
Omer Lutfi Sen ◽  
Yasemin Ezber ◽  
Deniz Bozkurt
Keyword(s):  
Climate Variability ◽  
Mediterranean Climate ◽  
Potential Role ◽  
East Asian ◽  
Boreal Winter ◽  
East Asian Trough

Differences in East Asian Self-Gifting and Role of Independence Within Interdependent Cultures

2013 ◽  
Author(s):  
Satoko Suzuki ◽  
Kosuke Takemura ◽  
Takeshi Hamamura
Keyword(s):  
East Asian

The Disciplinary Role of Leverage: Evidence from East Asian Acquirers

2014 ◽  
Author(s):  
Minh Thao Ngo ◽  
Robert B. Durand ◽  
Elaine Laing
Keyword(s):  
East Asian

scholarly journals A Climatological Assessment of Intense Desert Dust Episodes over the Broader Mediterranean Basin Based on Satellite Data

2021 ◽  
Vol 13 (15) ◽  
pp. 2895
Author(s):  
Maria Gavrouzou ◽  
Nikolaos Hatzianastassiou ◽  
Antonis Gkikas ◽  
Christos J. Lolis ◽  
Nikolaos Mihalopoulos
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Mean Value ◽  
Early Spring ◽  
Dust Aerosol ◽  
Ozone Monitoring Instrument ◽  
Central Mediterranean ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

A satellite algorithm able to identify Dust Aerosols (DA) is applied for a climatological investigation of Dust Aerosol Episodes (DAEs) over the greater Mediterranean Basin (MB), one of the most climatologically sensitive regions of the globe. The algorithm first distinguishes DA among other aerosol types (such as Sea Salt and Biomass Burning) by applying threshold values on key aerosol optical properties describing their loading, size and absorptivity, namely Aerosol Optical Depth (AOD), Aerosol Index (AI) and Ångström Exponent (α). The algorithm operates on a daily and 1° × 1° geographical cell basis over the 15-year period 2005–2019. Daily gridded spectral AOD data are taken from Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua Collection 6.1, and are used to calculate the α data, which are then introduced into the algorithm, while AI data are obtained by the Ozone Monitoring Instrument (OMI) -Aura- Near-UV aerosol product OMAERUV dataset. The algorithm determines the occurrence of Dust Aerosol Episode Days (DAEDs), whenever high loads of DA (higher than their climatological mean value plus two/four standard deviations for strong/extreme DAEDs) exist over extended areas (more than 30 pixels or 300,000 km2). The identified DAEDs are finally grouped into Dust Aerosol Episode Cases (DAECs), consisting of at least one DAED. According to the algorithm results, 166 (116 strong and 50 extreme) DAEDs occurred over the MB during the study period. DAEDs are observed mostly in spring (47%) and summer (38%), with strong DAEDs occurring primarily in spring and summer and extreme ones in spring. Decreasing, but not statistically significant, trends of the frequency, spatial extent and intensity of DAECs are revealed. Moreover, a total number of 98 DAECs was found, primarily in spring (46 DAECs) and secondarily in summer (36 DAECs). The seasonal distribution of the frequency of DAECs varies geographically, being highest in early spring over the eastern Mediterranean, in late spring over the central Mediterranean and in summer over the western MB.

scholarly journals The Less-Known History of the Voluntary Sector in an East Asian Welfare Regime: A South Korean Case

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Suyoung Kim
Keyword(s):  
East Asian ◽  
Voluntary Sector ◽  
Welfare States ◽  
Voluntary Organizations ◽  
Welfare Regime ◽  
Family Interactions ◽  
Welfare Regimes ◽  
South Korean ◽  
Welfare Mix

AbstractAlthough the voluntary sector is internationally valued as an integral component of the welfare mix, studies on East Asian welfare regimes have primarily focused on state-market-family interactions, paying scant attention to the long-standing and pivotal role of voluntary agencies in their construction. This case study illuminates this less-known aspect of modern welfare history in the context of South Korea, with a particular focus on the activities of voluntary organizations. The study categorizes South Korean voluntary associations into four types and examines their different contributions in shaping South Korea’s welfare regime, by applying Young’s framework on government–voluntary organizations relations. This historical exploration on the South Korean voluntary sector aims to deepen understanding of an East Asian welfare state regime. It further suggests that current welfare mix debates, focusing on the service delivery role of voluntary organizations within Western European welfare states, should be broadened.

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