排序方式： 共有7条查询结果，搜索用时 15 毫秒
1
1.
Based on a coupled ocean-sea ice model, this study investigates how changes in the mean state of the atmosphere in different CO_2 emission scenarios(RCP 8.5, 6.0, 4.5 and 2.6) may affect the sea ice in the Bohai Sea, China,especially in the Liaodong Bay, the largest bay in the Bohai Sea. In the RCP 8.5 scenario, an abrupt change of the atmospheric state happens around 2070. Due to the abrupt change, wintertime sea ice of the Liaodong Bay can be divided into 3 periods: a mild decreasing period(2021–2060), in which the sea ice severity weakens at a nearconstant rate; a rapid decreasing period(2061–2080), in which the sea ice severity drops dramatically; and a stabilized period(2081–2100). During 2021–2060, the dates of first ice are approximately unchanged, suggesting that the onset of sea ice is probably determined by a cold-air event and is not sensitive to the mean state of the atmosphere. The mean and maximum sea ice thickness in the Liaodong Bay is relatively stable before 2060, and then drops rapidly in the following decade. Different from the RCP 8.5 scenario, atmospheric state changes smoothly in the RCP 6.0, 4.5 and 2.6 scenarios. In the RCP 6.0 scenario, the sea ice severity in the Bohai Sea weakens with time to the end of the twenty-first century. In the RCP 4.5 scenario, the sea ice severity weakens with time until reaching a stable state around the 2070 s. In the RCP 2.6 scenario, the sea ice severity weakens until the2040 s, stabilizes from then, and starts intensifying after the 2080 s. The sea ice condition in the other bays of the Bohai Sea is also discussed under the four CO_2 emissions scenarios. Among atmospheric factors, air temperature is the leading one for the decline of the sea ice extent. Specific humidity also plays an important role in the four scenarios. The surface downward shortwave/longwave radiation and meridional wind only matter in certain scenarios, while effects from the zonal wind and precipitation are negligible. 相似文献
2.
海洋数值模式是精准海洋环境预报的核心手段。随着计算分辨率的不断提高,海洋数值模式对计算性能的要求也越来越高。为了提高模式计算性能,充分发挥现代计算机的特点,选取海洋环流模式NEMO开展了代码现代化优化方案在海洋环流模式中的应用研究。首先使用Intel性能分析工具对模式的计算性能进行了分析;随后,针对热点函数,开展了编译选项优化、标量串行代码优化、SIMD优化、内存带宽优化以及多进程扩展。结果显示:经过以上优化步骤,在不增加任何硬件成本的前提下,模式整体性能可提升31%,且在多进程下表现出了较好的负载均衡性。这表明,本研究采用的优化策略是一种切实可行的方法。在此基础上,进一步对代码现代化过程中出现的显著影响计算效率的问题,如大量指针的使用阻止矢量化、循环嵌套过多、内存带宽占用过高等,开展了分析和讨论,为未来模式的设计和改进提供了参考和建议。 相似文献
3.
北太平洋经向翻转环流(NPMOC)是北太平洋所有经向翻转环流圈的总称,拥有5个环流圈结构.其中,热带环流圈(TC)、副热带环流圈(STC)和深层热带环流圈(DTC)位于北太平洋热带-副热带海域,是该海域间经向物质和能量交换的重要通道.主要运用NEMO模式对这3个经向翻转环流圈的年际变化特征和机理进行了研究.结果表明,TC、STC和DTC的经向流量都具有显著的年际变化特征:在El Nio期间,TC的南、北向流量均减弱,STC的北向流量增强、南向流量减弱,DTC的南向流量减弱;而在La Nia期间则相反.敏感性试验表明,在风应力强迫下得到的TC、STC南、北向流量和DTC南向流量的年际变化特征都很显著,并与在风应力、热通量和淡水通量共同强迫下得到的结果非常一致;而仅在热通量和淡水通量的强迫下,各分支流量的年际变化均较小.由此可见,风场驱动是引起北太平洋经向翻转环流年际变化的主要驱动因素,而热通量和淡水通量的影响却较小. 相似文献
4.
The results of the analysis of the data collected with the NEMO Phase-2 tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are presented. Čerenkov photons detected with the photomultipliers tubes were used to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution was measured and the results compared with Monte Carlo simulations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is also included. The associated depth intensity relation was evaluated and compared with previous measurements and theoretical predictions. With the present analysis, the muon depth intensity relation has been measured up to 13 km of water equivalent. 相似文献
5.
This paper addresses the issue of the non conservation of tracer that occurs when a leapfrog time stepping scheme is used in association with a Robert-Asselin time filter within the framework of a time varying vertical coordinate system. A re-formulation of both the forcing and filtering terms that provides a globally conservative scheme is presented. Local conservation is then achieved when the model levels and subsequently the sea surface height satisfy a local compatibility condition. The properties of the resulting scheme are illustrated by a global coupled ocean–sea ice model based on the Nucleus for European Modelling of the Ocean (NEMO). 相似文献
6.
C. Distefano 《Astrophysics and Space Science》2007,309(1-4):415-420
The NEMO Collaboration is conducting an R&D activity towards the construction of a Mediterranean km3 neutrino telescope. In this work, we present the results of Monte Carlo simulation studies on the capability of the proposed
NEMO telescope to detect and identify point-like sources of high energy muon neutrinos.
C. Distefano for the NEMO Collaboration. 相似文献
7.
Shabnam JafariKhasragh Jennifer V. Lukovich Xianmin Hu Paul G. Myers Kevin Sydor David G. Barber 《大气与海洋》2013,51(2):120-133
ABSTRACTSea surface temperature (SST) from four Nucleus for European Modelling of the Ocean (NEMO) model simulations is analyzed to study the bulk flux parameterization to compute SST over the Hudson Bay Complex (HBC) for the summer months (August and September) from 2002 to 2009. The NEMO simulation was forced with two atmospheric forcing sets with different resolutions: the Coordinated Ocean-ice Reference Experiment, version 2 (COREv2), as the lower resolution and the Canadian Meteorological Centre’s Global Deterministic Prediction System Reforecasts (CGRF) as the higher resolution. The CGRF forcing is also implemented in the third and fourth runs using different runoff data and different NEMO resolutions (1/12° versus 1/4°). Results show that all four modelled SSTs followed observed SST patterns, with regional differences in SST bias between simulations with different atmospheric forcing. The SST differences are small between simulations forced with the same atmospheric forcing but with different model resolution or runoff. This implies that the model resolution and runoff have a small effect on the simulated SST in the HBC. Moreover, to better capture the effect of near-surface temperature (Tair) on simulated SST, we conducted three analyses using the Haney flux linearization formula. Results from these assessments did not indicate any direct influence on the model-simulated SSTs by Tair. Looking at the heat flux as a signature for SST showed that both averaged spatial distribution and time series of net heat flux produced by the three CGRF forcing simulations were higher than the net heat flux generated by the CORE 2 simulation. This was generally true for all four components of the total heat flux (sensible, latent, shortwave, and longwave) individually as well. Total heat flux in summer is governed by the shortwave heat flux, with values up to 120?W?m?2 in August, and the longwave heat flux is the main contributor to the total heat flux differences. These heat flux differences lead to corresponding colder model SSTs for the CGRF runs and warmer SSTs for the CORE 2 simulations. 相似文献
1