The Experts below are selected from a list of 43902 Experts worldwide ranked by ideXlab platform
V. Pont - One of the best experts on this subject based on the ideXlab platform.
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Medium-range mid-tropospheric transport of ozone and precursors over Africa: two numerical case studies in dry and wet seasons
Atmospheric Chemistry and Physics, 2007Co-Authors: B. Sauvage, F. Gheusi, V. Thouret, Jean-pierre Cammas, J. Duron, J. Escobar, C. Mari, P. Mascart, V. PontAbstract:A meso-scale model was used to understand and describe the dynamical processes driving high ozone concentrations observed during both dry and monsoon season in monthly climatologies profiles over Lagos (Nigeria, 6.6° N, 3.3° E), obtained with the MOZAIC airborne measurements (ozone and carbon monoxide). This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, around 3000 m. Two individual cases have been selected in the MOZAIC dataset as being representative of the climatological ozone enhancements, to be simulated and analyzed with on-line Lagrangian backtracking of air masses. This study points out the role of baroclinic low-level circulations present in the Inter Tropical Front (ITF) area. Two low-level thermal cells around a zonal axis and below 2000 m, in mirror symmetry to each other with respect to equator, form near 20° E and around 5° N and 5° S during the (northern hemisphere) dry and wet seasons respectively. They are caused by surface gradients – the warm dry surface being located poleward of the ITF and the cooler wet surface equatorward of the ITF. A convergence line exists between the poleward low-level branch of each thermal cell and the equatorward low-level branch of the Hadley cell. Our main conclusion is to point out this line as a preferred location for fire products – among them ozone precursors – to be uplifted and injected into the lower free troposphere. The free tropospheric transport that occurs then depends on the hemisphere and season. In the NH dry season, the AEJ allows transport of ozone and precursors westward to Lagos. In the NH monsoon (wet) season, fire products are transported from the southern hemisphere to Lagos by the southeasterly Trade that surmounts the monsoon layer. Additionally ozone precursors uplifted by wet convection in the ITCZ can also mix to the ones uplifted by the baroclinic cell and be advected up to Lagos by the Trade Flow.
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Medium-range mid-tropospheric transport of ozone and precursors over Africa: two numerical case-studies in dry and wet seasons
Atmospheric Chemistry and Physics Discussions, 2007Co-Authors: B. Sauvage, F. Gheusi, V. Thouret, Jean-pierre Cammas, J. Duron, J. Escobar, C. Mari, P. Mascart, V. PontAbstract:A meso-scale model was used to understand and describe the processes driving high ozone concentrations observed during both dry and monsoon seasons in monthly climatologies profiles over Lagos (Nigeria, 6.6° N, 3.3° E), obtained with the MOZAIC airborne measurements (ozone and carbon monoxide). This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, around 3000 m. Two individual cases have been selected in the MOZAIC dataset as being representative of the climatological ozone enhancements, to be simulated and analyzed with on-line Lagrangian backtracking of airmasses. This study points out the role of baroclinic low-level circulations present in the Inter Tropical Front (ITF) area. Two low-level thermal cells around a zonal axis and below 2000 m, in mirror symmetry to eachother with respect to equator, form near 20° E and around 5° N and 5° S during the (northern hemisphere) dry and wet seasons respectively. They are caused by surface gradients – the warm dry surface being located poleward of the ITF and the cooler wet surface equatorward of the ITF. A convergence line exists between the poleward low-level branch of each thermal cell and the equatorward low-level branch of the Hadley cell. Our main conclusion is to point out this line as a preferred location for fire products – among them ozone precursors – to be uplifted and injected into the lower free troposphere. The free tropospheric transport that occurs then depends on the hemisphere and season. In the NH dry season, the African Easterly Jet allows transport of ozone and precursors westward to Lagos. In the NH monsoon (wet) season, fire products are transported from the southern hemisphere to Lagos by the southeasterly Trade that surmounts the monsoon layer. Additionally ozone precursors uplifted by wet convection in the Inter Tropical Convergence Zone can also mix to the ones uplifted by the baroclinic cell and be advected up to Lagos by the Trade Flow.
Zhifu Mi - One of the best experts on this subject based on the ideXlab platform.
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optimization of virtual water Flow via grain Trade within china
Ecological Indicators, 2019Co-Authors: Zongzhi Wang, Xueli Ding, Jinwei Wang, Lingling Zhang, Qing Zhang, Zhifu MiAbstract:Abstract The irrational virtual water Flow caused by grain Trade makes water use efficiency low and further threatens grain security in China. However, optimizing the grain virtual water Trade Flow from the perspective of the economic value of water resources has rarely been carried out in current research. This paper proposes a linear optimization model considering opportunity cost to fill this gap. The current situation of grain virtual water Trade is analyzed and we find an irrational Trade mode which quantity and direction of grain virtual water Trade in some provinces are not consistent with actual demand. Then, opportunity cost is added to the linear optimization model to adjust grain virtual water Trade which shows several advantages compared to general linear optimization model. Results show that huge virtual Flow is generated, up to 1179.24 billion cubic meters of water. And the economic value generated by grain virtual water Trade can not only cover the transportation cost but can also eventually generate economic benefits of 7410 billion yuan. Finally, the relevant conclusions and implications of adjusting China’s grain virtual water Trade are obtained.
B. Sauvage - One of the best experts on this subject based on the ideXlab platform.
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Medium-range mid-tropospheric transport of ozone and precursors over Africa: two numerical case studies in dry and wet seasons
Atmospheric Chemistry and Physics, 2007Co-Authors: B. Sauvage, F. Gheusi, V. Thouret, Jean-pierre Cammas, J. Duron, J. Escobar, C. Mari, P. Mascart, V. PontAbstract:A meso-scale model was used to understand and describe the dynamical processes driving high ozone concentrations observed during both dry and monsoon season in monthly climatologies profiles over Lagos (Nigeria, 6.6° N, 3.3° E), obtained with the MOZAIC airborne measurements (ozone and carbon monoxide). This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, around 3000 m. Two individual cases have been selected in the MOZAIC dataset as being representative of the climatological ozone enhancements, to be simulated and analyzed with on-line Lagrangian backtracking of air masses. This study points out the role of baroclinic low-level circulations present in the Inter Tropical Front (ITF) area. Two low-level thermal cells around a zonal axis and below 2000 m, in mirror symmetry to each other with respect to equator, form near 20° E and around 5° N and 5° S during the (northern hemisphere) dry and wet seasons respectively. They are caused by surface gradients – the warm dry surface being located poleward of the ITF and the cooler wet surface equatorward of the ITF. A convergence line exists between the poleward low-level branch of each thermal cell and the equatorward low-level branch of the Hadley cell. Our main conclusion is to point out this line as a preferred location for fire products – among them ozone precursors – to be uplifted and injected into the lower free troposphere. The free tropospheric transport that occurs then depends on the hemisphere and season. In the NH dry season, the AEJ allows transport of ozone and precursors westward to Lagos. In the NH monsoon (wet) season, fire products are transported from the southern hemisphere to Lagos by the southeasterly Trade that surmounts the monsoon layer. Additionally ozone precursors uplifted by wet convection in the ITCZ can also mix to the ones uplifted by the baroclinic cell and be advected up to Lagos by the Trade Flow.
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Medium-range mid-tropospheric transport of ozone and precursors over Africa: two numerical case-studies in dry and wet seasons
Atmospheric Chemistry and Physics Discussions, 2007Co-Authors: B. Sauvage, F. Gheusi, V. Thouret, Jean-pierre Cammas, J. Duron, J. Escobar, C. Mari, P. Mascart, V. PontAbstract:A meso-scale model was used to understand and describe the processes driving high ozone concentrations observed during both dry and monsoon seasons in monthly climatologies profiles over Lagos (Nigeria, 6.6° N, 3.3° E), obtained with the MOZAIC airborne measurements (ozone and carbon monoxide). This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, around 3000 m. Two individual cases have been selected in the MOZAIC dataset as being representative of the climatological ozone enhancements, to be simulated and analyzed with on-line Lagrangian backtracking of airmasses. This study points out the role of baroclinic low-level circulations present in the Inter Tropical Front (ITF) area. Two low-level thermal cells around a zonal axis and below 2000 m, in mirror symmetry to eachother with respect to equator, form near 20° E and around 5° N and 5° S during the (northern hemisphere) dry and wet seasons respectively. They are caused by surface gradients – the warm dry surface being located poleward of the ITF and the cooler wet surface equatorward of the ITF. A convergence line exists between the poleward low-level branch of each thermal cell and the equatorward low-level branch of the Hadley cell. Our main conclusion is to point out this line as a preferred location for fire products – among them ozone precursors – to be uplifted and injected into the lower free troposphere. The free tropospheric transport that occurs then depends on the hemisphere and season. In the NH dry season, the African Easterly Jet allows transport of ozone and precursors westward to Lagos. In the NH monsoon (wet) season, fire products are transported from the southern hemisphere to Lagos by the southeasterly Trade that surmounts the monsoon layer. Additionally ozone precursors uplifted by wet convection in the Inter Tropical Convergence Zone can also mix to the ones uplifted by the baroclinic cell and be advected up to Lagos by the Trade Flow.
Ankai Xu - One of the best experts on this subject based on the ideXlab platform.
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Trade in Virtual Water: Do Property Rights Matter?
Water Resources Management, 2018Co-Authors: Ankai XuAbstract:This paper examines the determinants of virtual water Trade – embodied in agricultural products – and tests the relationship between property rights and the export of water-intensive products. Using two different measures of property rights protection, I show that countries with weaker property rights have an apparent comparative advantage in the export of water-intensive products. After controlling for economic size, natural resource endowments and bilateral Trade determinants, the Trade Flow of virtual water is negatively and significantly correlated with the property rights index of the exporting country. The results are robust across different estimation methods.
Zongzhi Wang - One of the best experts on this subject based on the ideXlab platform.
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optimization of virtual water Flow via grain Trade within china
Ecological Indicators, 2019Co-Authors: Zongzhi Wang, Xueli Ding, Jinwei Wang, Lingling Zhang, Qing Zhang, Zhifu MiAbstract:Abstract The irrational virtual water Flow caused by grain Trade makes water use efficiency low and further threatens grain security in China. However, optimizing the grain virtual water Trade Flow from the perspective of the economic value of water resources has rarely been carried out in current research. This paper proposes a linear optimization model considering opportunity cost to fill this gap. The current situation of grain virtual water Trade is analyzed and we find an irrational Trade mode which quantity and direction of grain virtual water Trade in some provinces are not consistent with actual demand. Then, opportunity cost is added to the linear optimization model to adjust grain virtual water Trade which shows several advantages compared to general linear optimization model. Results show that huge virtual Flow is generated, up to 1179.24 billion cubic meters of water. And the economic value generated by grain virtual water Trade can not only cover the transportation cost but can also eventually generate economic benefits of 7410 billion yuan. Finally, the relevant conclusions and implications of adjusting China’s grain virtual water Trade are obtained.
