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Alexandra Weiss Joachim Kuss Gerhard Peters Bernd Schneider 《Journal of Marine Systems》2007,66(1-4):130
Long-term observations of the marine atmospheric boundary layer were performed by an eddy correlation system, which was set-up on a platform in the Baltic Sea. In this experiment the three-dimensional wind vector and the turbulent fluxes of momentum, sensible and latent heat and CO2 were measured for one and a half years. Simultaneously the CO2 partial pressure pCO2 in surface water was measured by a submersible autonomous moored instrument for CO2 at the platform in 7-m depth. The high-resolution eddy correlation measurements of the atmospheric CO2 flux FCO2, together with the measurements of the CO2 partial pressure differences between air and sea ΔpCO2 led to a long-term data set which provided the possibility to investigate the parameterization of the CO2 transfer velocity k as a function of 10-m wind speed u in a statistical manner. From half-hour mean CO2 fluxes and CO2 partial pressure differences, k was calculated using k = FCO2 / (K0ΔpCO2), with K0 the CO2 solubility. The half-hour mean data points, used for the determination of the k–u parameterization, show large scatter. However, assuming a linear, quadratic dependency the analysis yields: k660 = 0.365u2 + 0.46u (k at 20 °C and salinity 35 psu) with a correlation coefficient of r2 = 0.81. The large scatter indicates that the kinetics of the air–sea CO2 transfer velocity is not only a function of the wind speed alone, but might also be controlled by other environmental parameters and mechanisms, such as sea state and surface coverage with surfactants. 相似文献
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Alexandra Hyard 《Transportation Research Part A: Policy and Practice》2012,46(4):707-719
Made compulsory in France for major transport infrastructures, cost-benefit analysis is constantly being improved to achieve the best socio-economic evaluation possible. According to the philosopher and economist Amartya Sen, this analysis should meet two requirements: one ethical, the other democratic. We will examine the evaluation procedure in France and highlight the gap between its officially more democratic character and its still insufficiently ethical character, from the viewpoint of this dual requirement. 相似文献
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