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21.
Decadal variability of subsurface temperature in the North Pacific has been investigated. Two dominant regions were found;
the central subarctic region (CSa) and the north-eastern subtropical region (NESt). In CSa, cooling (warming) of wintertime
subsurface temperature corresponds to the large (small) temperature gradient and southward (northward) shift of subsurface
temperature front, associated with the increase (decrease) of positive wind stress curl and the southward (northward) shift
of curl τ zero line with 2 years delay. It is suggested that the relocation of subtropical-subarctic boundary plays an important
role. In NESt, importance of heat flux through the sea surface and heat divergence in the Ekman layer is also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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24.
A surface panel method treating a boundary-value problem of the Dirichlet type with the free surface is presented to design a three-dimensional body corresponding to a prescribed pressure distribution. The free surface boundary condition is linearized with respect to the oncoming flow, and computed by four-point finite difference scheme. Sample designs for submerged spheroids and Wigley hull are carried out to demonstrate the stable convergence, the effectiveness and the robustness of the method. The design of a 5500TEU container carrier is performed with respect to reduction of the wave resistance. To reduce the wave resistance, calculated pressure on the hull surface is modified to have the lower fluctuation, and is applied as a Dirichlet type dynamic boundary condition on the hull surface. The designed hull form is verified to have the lower wave resistance than the initial one not only by computation but also by experiment. 相似文献
25.
给出并讨论了海洋系统中由于热量交换、物质交换以及外力做功引起的熵通量的表达式;同时,根据新近调整的全球海 气界面的气候平均资料,估计了全球海洋与大气界面气候年平均的熵通量(熵流),这一熵通量主要取决于海 气界面的热量和物质交换的空间不均匀性。计算结果显示,由热量交换分量引起的熵通量对海洋系统的总熵通量起到主要的贡献作用,其值约为-555.6mW·(m2·K)-1;由海表风应力做功引起的熵通量相对较小,约为-0.09mW·(m2·K)-1;由物质交换引起的熵通量最小,仅为-0.02mW·(m2·K)-1。总的来说,海洋系统从外界获得的总熵通量为-555.7mW·(m2·K)-1,这也就意味着在气候平均定态下,海洋系统内部的熵产生在量值上等于系统的熵交换,即为555.7mW·(m2·K)-1。海洋系统的负熵流与其内部的各种不可逆过程引起的熵产生取得平衡,确保了全球海洋系统处于非平衡热力学定态,并维持着海洋系统中各种尺度的时 空有序现象的消长过程。 相似文献
26.
Seasonal and annual variations of marine sinking particulate flux during 1993~1996 in the central South China Sea 总被引:1,自引:0,他引:1
CHEN Ronghu WIESNER M G ZHENG Yulong CHENG Xinrong JIN Haiyan ZHAO Qingying ZHENG Lianfu 《海洋学报(英文版)》2007,26(3):33-43
A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993~1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species (Globigerinoides sacculifer, G. ruber, Globigerinita glutinata, Neogloboquadrina dutertrei) and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution. 相似文献
27.
对类比路段进行连续模拟试验,进行现场调查,给出汽车尾气主要污染物的排污强度,预测了汽车尾气中CO、C_nH_m和NO_x的扩散范围。 相似文献
28.
Richard N. Hey Gary J. Massoth Robert C. Vrijenhoek Peter A. Rona John Lupton David A. Butterfield 《Marine Geophysical Researches》2006,27(2):137-153
Earth’s fastest present seafloor spreading occurs along the East Pacific Rise near 31°–32° S. Two of the major hydrothermal
plume areas discovered during a 1998 multidisciplinary geophysical/hydrothermal investigation of these mid-ocean ridge axes
were explored during a 1999 Alvin expedition. Both occur in recently eruptive areas where shallow collapse structures mark
the neovolcanic axis. The 31° S vent area occurs in a broad linear zone of collapses and fractures coalescing into an axial
summit trough. The 32° S vent area has been volcanically repaved by a more recent eruption, with non-linear collapses that
have not yet coalesced. Both sites occur in highly inflated areas, near local inflation peaks, which is the best segment-scale
predictor of hydrothermal activity at these superfast spreading rates (150 mm/yr). 相似文献
29.
胶莱盆地发育演化及其油气前景探讨 总被引:5,自引:0,他引:5
根据胶莱盆地区域地质特征,地球动力学背景及盆地中、新生代沉积特征分析,论述盆地的发育和演化阶段,并对胶莱盆地含油气前景进行探讨。 相似文献
30.
We study the reaction of a global ocean–sea ice model to an increase of fresh water input into the northern North Atlantic under different surface boundary conditions, ranging from simple restoring of surface salinity to the use of an energy balance model (EBM) for the atmosphere. The anomalous fresh water flux is distributed around Greenland, reflecting increased melting of the Greenland ice sheet and increasing fresh water export from the Arctic Ocean. Depending on the type of surface boundary condition, the large circulation reacts with a slow-down of overturning and gyre circulations. Restoring of the total or mean surface salinity prevents a large scale redistribution of the salinity field that is apparent under mixed boundary conditions and with the EBM. The control run under mixed boundary conditions exhibits large and unrealistic oscillations of the meridional overturning. Although the reaction to the fresh water flux anomaly is similar to the response with the EBM, mixed boundary conditions must thus be considered unreliable. With the EBM, the waters in the deep western boundary current initially become saltier and a new fresh water mass forms in the north-eastern North Atlantic in response to the fresh water flux anomaly around Greenland. After an accumulation period of several decades duration, this new North East Atlantic Intermediate Water spreads towards the western boundary and opens a new southward pathway at intermediate depths along the western boundary for the fresh waters of high northern latitudes. 相似文献