Two important nonlinear properties of seawater thermodynamics linked to changes of water density, cab beling and elasticity （compressibility）, are discussed. Eddy diffusion and advection lead to changes in den sity;...Two important nonlinear properties of seawater thermodynamics linked to changes of water density, cab beling and elasticity （compressibility）, are discussed. Eddy diffusion and advection lead to changes in den sity; as a result, gravitational potential energy of the system is changed. Therefore, cabbeling and elasticity play key roles in the energetics of lateral eddy diffusion and advection. Vertical eddy diffusion is one of the key elements in the mechanical energy balance of the global oceans. Vertical eddy diffusion can be con ceptually separated into two steps： stirring and subscale diffusion. Vertical eddy stirring pushes cold/dense water upward and warm/light water downward; thus, gravitational potential energy is increased. During the second steps, water masses from different places mix through subscale diffusion, and water density is increased due to cabbeling. UsingWOA01 climatology and assuming the vertical eddy diffusivity is equal to a constant value of 2x103 pa2/s, the total amount of gravitational potential energy increase due to vertical stirring in the world oceans is estimated at 263 GW. Cabbeling associated with vertical subscale diffusion is a sink of gravitational potential energy, and the total value of energy lost is estimated at 73 GW. Therefore, the net source of gravitational potential energy due to vertical eddy diffusion for the world oceans is estimated at 189 GW.展开更多
Mountain regions play an increasingly essential role in global sustainable development, and the related sustainable development issues have attracted increasing attention. There are obvious vertical spatial differenti...Mountain regions play an increasingly essential role in global sustainable development, and the related sustainable development issues have attracted increasing attention. There are obvious vertical spatial differentiation phenomena in both natural and socio-eeonomic fields with altitude being a key factor affecting the economic development of mountain regions. However, the exact influence of altitude is still unknown. Based on the county scale, this paper used the gravitational potential energy model to evaluate the effects of altitude on economic development in China. The results indicate that the high-altitude areas were the depression areas of county economic development, and county economic density showed a decreasing trend with the increase of altitude. County economic density respectively decreased by 0.10%, 0.04% and 0.02% with every 1% increase in altitude in 2000, 2005 and 2010. Here we demonstrate that high altitude has negative effect on county economy, although the negative effect presented a downward trend. The results also showed that increasing capital and labor investments could reduce the negative effect of high altitude on county economy. In 2010, with every 1% increase in capital and labor density, county economic density increased by 0.62% and 0.83%, respectively. The effects of altitude were the results of multidimensional factors. The fundamental approach to reduce the negative effects of high altitude is to combine the ecological environment and resources to develop characteristic industries. The construction of infrastructure should be strengthened, which can promote the occurrence of the contra-flow of people, logistics and capital, and promote the balanced development of county economy.展开更多
文摘Two important nonlinear properties of seawater thermodynamics linked to changes of water density, cab beling and elasticity （compressibility）, are discussed. Eddy diffusion and advection lead to changes in den sity; as a result, gravitational potential energy of the system is changed. Therefore, cabbeling and elasticity play key roles in the energetics of lateral eddy diffusion and advection. Vertical eddy diffusion is one of the key elements in the mechanical energy balance of the global oceans. Vertical eddy diffusion can be con ceptually separated into two steps： stirring and subscale diffusion. Vertical eddy stirring pushes cold/dense water upward and warm/light water downward; thus, gravitational potential energy is increased. During the second steps, water masses from different places mix through subscale diffusion, and water density is increased due to cabbeling. UsingWOA01 climatology and assuming the vertical eddy diffusivity is equal to a constant value of 2x103 pa2/s, the total amount of gravitational potential energy increase due to vertical stirring in the world oceans is estimated at 263 GW. Cabbeling associated with vertical subscale diffusion is a sink of gravitational potential energy, and the total value of energy lost is estimated at 73 GW. Therefore, the net source of gravitational potential energy due to vertical eddy diffusion for the world oceans is estimated at 189 GW.
基金funded by the National Natural Science Foundation of China (Grants No.41571523)the National Science and Technology Support Program (Grant No.2014BAC05B01)the National Key Basic Research and Development Program of China (973 Program) (Grant No.2013CBA01808)
文摘Mountain regions play an increasingly essential role in global sustainable development, and the related sustainable development issues have attracted increasing attention. There are obvious vertical spatial differentiation phenomena in both natural and socio-eeonomic fields with altitude being a key factor affecting the economic development of mountain regions. However, the exact influence of altitude is still unknown. Based on the county scale, this paper used the gravitational potential energy model to evaluate the effects of altitude on economic development in China. The results indicate that the high-altitude areas were the depression areas of county economic development, and county economic density showed a decreasing trend with the increase of altitude. County economic density respectively decreased by 0.10%, 0.04% and 0.02% with every 1% increase in altitude in 2000, 2005 and 2010. Here we demonstrate that high altitude has negative effect on county economy, although the negative effect presented a downward trend. The results also showed that increasing capital and labor investments could reduce the negative effect of high altitude on county economy. In 2010, with every 1% increase in capital and labor density, county economic density increased by 0.62% and 0.83%, respectively. The effects of altitude were the results of multidimensional factors. The fundamental approach to reduce the negative effects of high altitude is to combine the ecological environment and resources to develop characteristic industries. The construction of infrastructure should be strengthened, which can promote the occurrence of the contra-flow of people, logistics and capital, and promote the balanced development of county economy.
