The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling(WAM) program proposed by Hasselmann...The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling(WAM) program proposed by Hasselmann and Komen and the other provided by Tsagareli and Babanin. The solution adopted for our study was presented by Song for the wave-modifi ed Ekman current model that included the Stokes drift, wind input, and wave dissipation with eddy viscosity increasing linearly with depth. Using the Combi spectrum with tail effects, the solutions are calculated using two formulations for wind input and wave dissipation, and compared. Differences in the results are not negligible. Furthermore, the solution presented by Song and Xu for the eddy viscosity formulated using the K-Profi le Parameterization scheme under wind input and wave dissipation given by Tsagareli and Babanin is compared with that obtained for a depth-dependent eddy viscosity. The solutions are further compared with the available well-known observational data. The result indicates that the Tsagareli and Babanin scheme is more suitable for use in the model when capillary waves are included, and the solution calculated using the K-Profi le Parameterization scheme agrees best with observations.展开更多
We explore the ultimate fate of the Universe by using a divergence-free parametrization for dark energy w（z）=w0＋wa, [In（2 ＋ z） / （1 ＋ z） - In 2] . Unlike the Chevallier-Polarski-Linder parametrization, this p...We explore the ultimate fate of the Universe by using a divergence-free parametrization for dark energy w（z）=w0＋wa, [In（2 ＋ z） / （1 ＋ z） - In 2] . Unlike the Chevallier-Polarski-Linder parametrization, this parametrization has well behaved, bounded behavior for both high redshifts and negative redshifts, and thus can genuinely cover many theoretical dark energy models. Alter constraining the parameter space of this parametrization by using the current cosmological observations, we find that, at the 95.4% confidence level, our Universe can still exist at least 16.7 Gyr before it ends in a big rip. Moreover, for the phantom energy dominated Universe, we find that a gravitationally bound system will be destroyed at a time t = P√2｜ 1 ＋ 3w（ 1）] / [6π] 1 ＋ w（-1）｜], where P is the period of a circular orbit around this system, before the big rip.展开更多
基金Supported by the National Natural Science Foundation of China(No.41176016)the National Basic Research Program of China(973 Program)(Nos.2012CB417402,2011CB403501)the Fund for Creative Research Groups by National Natural Science Foundation of China(No.41121064)
文摘The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling(WAM) program proposed by Hasselmann and Komen and the other provided by Tsagareli and Babanin. The solution adopted for our study was presented by Song for the wave-modifi ed Ekman current model that included the Stokes drift, wind input, and wave dissipation with eddy viscosity increasing linearly with depth. Using the Combi spectrum with tail effects, the solutions are calculated using two formulations for wind input and wave dissipation, and compared. Differences in the results are not negligible. Furthermore, the solution presented by Song and Xu for the eddy viscosity formulated using the K-Profi le Parameterization scheme under wind input and wave dissipation given by Tsagareli and Babanin is compared with that obtained for a depth-dependent eddy viscosity. The solutions are further compared with the available well-known observational data. The result indicates that the Tsagareli and Babanin scheme is more suitable for use in the model when capillary waves are included, and the solution calculated using the K-Profi le Parameterization scheme agrees best with observations.
基金supported by the Project of Knowledge Innovation Program of Chinese Academy of Sciencesthe National Natural Science Foundation of China (Grant Nos. 11105053, 10705041, 10975032, 11175042,10535060, 10975172 and 10821504)+1 种基金the National Ministry of Education of China (Grant Nos. NCET-09-0276 and N100505001)the National Basic Research Program of China (Grant No. 2007CB815401)
文摘We explore the ultimate fate of the Universe by using a divergence-free parametrization for dark energy w（z）=w0＋wa, [In（2 ＋ z） / （1 ＋ z） - In 2] . Unlike the Chevallier-Polarski-Linder parametrization, this parametrization has well behaved, bounded behavior for both high redshifts and negative redshifts, and thus can genuinely cover many theoretical dark energy models. Alter constraining the parameter space of this parametrization by using the current cosmological observations, we find that, at the 95.4% confidence level, our Universe can still exist at least 16.7 Gyr before it ends in a big rip. Moreover, for the phantom energy dominated Universe, we find that a gravitationally bound system will be destroyed at a time t = P√2｜ 1 ＋ 3w（ 1）] / [6π] 1 ＋ w（-1）｜], where P is the period of a circular orbit around this system, before the big rip.
