Simulated Spatial Distribution and Seasonal Variation of Atmospheric Methane over China:Contributions from Key Sources

We used the global atmospheric chemical transport model,GEOS-Chem,to simulate the spatial distribution and seasonal variation of surface-layer methane （CH4） in 2004,and quantify the impacts of individual domestic sources and foreign transport on CH4 concentrations over China.Simulated surface-layer CH4 concentrations over China exhibit maximum concentrations in summer and minimum concentrations in spring.The annual mean CH4 concentrations range from 1800 ppb over western China to 2300 ppb over the more populated eastern China.Foreign emissions were found to have large impacts on CH4 concentrations over China,contributing to about 85％ of the CH4 concentrations over western China and about 80％ of those over eastern China.The tagged simulation results showed that coal mining,livestock,and waste are the dominant domestic contributors to CH4 concentrations over China,accounting for 36％,18％,and 16％,respectively,of the annual and national mean increase in CH4 concentration from all domestic emissions.Emissions from rice cultivation were found to make the largest contributions to CH4 concentrations over China in the summer,which is the key factor that leads to the maximum seasonal mean CH4 concentrations in summer.

Securitization and De-securitization􀋖Turkey-Syria Relations since the Syrian Crisis

The article focuses on the nature of the relations between Turkey and Syria during the Syrian crisis.Although the relationship between Turkey and Syria had undergone some ups and downs in the last several years,both countries tried their best to improve their economic,political,cultural,and diplomatic relations.Indeed,Turkey introduced its model,“Moderate Islamic ideologies”,through Syria in the Middle East and North Africa(MENA).The“Arab Spring”of 2011 was a very good opportunity for Turkey to introduce its democratic Islamic dogmas which were welcomed by the Muslim Brotherhood leaders in some Arab Countries.But,the President of Syria,Bashar Al Assad,and his allies were very critical of Turkey’s policy.Thus,the article mainly explores the role of Turkey in Syria’s internal affairs,in particular,Erdogan’s policy towards Syrian crises.Besides,it examines Turkey’s domestic challenges and how Turkey has presented itself as a big supporter of the Arab Spring in the MENA.However,the article has found out that the current policies of Turkey towards the Syrian crisis are critical within the Middle East region.In other words,the conflicts and the wars against the Islamic State(ISIS)and the Kurdistan Workers’Party(PKK)weakened the bilateral relations.The Syrian refugees and the PKK are posing overwhelming challenges to Turkey’s economy and internal security.