The three-dimensional structure and seasonal variation of the North Pacific meridional overturning circulation

The three-dimensional structure and the seasonal variation of the North Pacific meridional overturning circulation （NPMOC） are analyzed based on the Simple Ocean Data Assimilation data and Argo profiling float data. The NPMOC displays a multi-cell structure with four cells in the North Pacific altogether. The TC and the STC are a strong clockwise meridional cell in the low latitude ocean and a weaker clockwise meridional cell between 7°N and 18°N, respectively, while the DTC and the subpolar cell are a weaker anticlockwise meridional cell between 3°N and 15°N and a weakest anticlockwise meridional cell between 35°N and 50°N, respectively. The DTC, the TC and the STC are all of very strong seasonal variations. As to the DTC, the southward transport is strongest in fall and weakest in spring. For the TC, the northward transport is strongest in winter and weakest in spring, while the southward transport is strongest in fall and weakest in spring, which is associated with the strong southward fiow of the DTC in fall. As the STC, the northward transport is strongest in winter and weakest in summer, while the southward transport is strongest in summer and weakest in spring. This seasonal difference may be associated with the DTC. The zonal wind stress and the east-west slope of sea level play important roles in the seasonal variations of the TC, the STC and the DTC.

Fluid structure interaction for circulation valve of hydraulic shock absorber

Based on the working principle and the damping characteristic of hydraulic shock absorber, a fluid structure interaction method was presented, which was used to analyze the microcosmic and high-frequency processing mechanism of fluid structure interaction between circulation valve and liquid of hydraulic shock absorber. The fluid mesh distortion was controlled by the CEL language, and the fluid struc^tre interaction mathematical model was established. The finite element model was established by ANSYS CFX software and was analyzed by dynamic mesh technique. The local sensitive computational area was meshed by prismatic grid, which could reduce the negative volume problem during the simulation. The circulation valve and liquid of hydraulic shock absorber were simulated and analyzed under the condition of sinusoidal inlet velocity loads. Flow characteristic and dynamics characteristic were obtained. The pressure distribution and the displacement of circulation value were obtained, and the acceleration curve of circulation valve was simulated and analyzed. The conformity of the final simulation results with the experimental datum indicates that this method is accurate and reliable to analyze the dynamics characteristic between circulation valve and liquid of hydraulic shock absorber, which can provide a theoretical foundation for optimizing hydraulic shock absorber in the future.

Water exchange and circulation structure near the Luzon Strait in early summer

Using hydrographic data covering large areas of ocean for the period from June 21 to July 5 in 2009, we studied the circulation structure in the Luzon Strait area, examined the routes of water exchange between the South China Sea （SCS） and the Philippine Sea, and estimated the volume transport through Luzon Strait. We found that the Kuroshio axis follows a e-shaped path slightly east of 121°E in the upper layer. With an increase in depth, the Kuroshio axis became gradually farther from the island of Luzon. To study the water exchange between the Philippine Sea and the SCS, identification of inflows and outflows is necessary. We first identified which flows contributed to the water exchange through Luzon Strait, which differs from the approach taken in previous studies. We determined that the obvious water exchange is in the section of 121°E. The westward inflow from the Philippine Sea into the SCS is 6.39 Sv in volume, and mainly in the 100-500 m layer at 19.5°-20°N （accounting for 4.40 Sv）, while the outflow from the SCS into the Philippine Sea is concentrated in the upper 100 m at 19°-20°N and upper 400 m at 21°-21.5°N, and below 240 m at 19°-19.5°N, accounting for 1.07, 3.02 and 3.43 Sv in volume transport, respectively.

THE DOUBLE-LAYER STRUCTURE OF THE HADLEY CIRCULATION AND ITS INTERDECADAL EVOLUTION CHARACTERISTICS

Based on the three-pattern decomposition of global atmospheric circulation(TPDGAC), this study investigates the double-layer structure of the Hadley circulation(HC) and its interdecadal evolution characteristics by using monthly horizontal wind field from NCEP/NCAR reanalysis data from 1948—2011. The following major conclusions are drawn: First, the double-layer structure of the HC is an objective fact, and it constantly exists in April,May, June, October and November in the Southern Hemisphere. Second, the double-layer structure is more obvious in the Southern than in the Northern Hemisphere. Since the double-layer structure is sloped in the vertical direction, it should be taken into consideration when analyzing the variations of the strength and location of the center of the HC.Third, the strength of the double-layer structure of the HC in the Southern Hemisphere consistently exhibits decadal variations with a strong, weak and strong pattern in all five months(April, May, June, October, and November), with cycles of 20-30 a and 40-60 a. Fourth, the center of the HC(mean position of the double-layer structure) in the Southern Hemisphere consistently and remarkably shifts southward in all the five months. The net poleward shifts over the 64 years are 5.18°, 2.11°, 2.50°, 1.79° and 5.76° for the five respective months, with a mean shift of 3.47°.

A Method for Diagnosing the Secondary Circulation with Saturated Moist Entropy Structure in a Mature Tropical Cyclone

Under the adiabatic, axisymmetric and steady assumption, a relationship between the saturated moist entropy structure and the secondary circulation in a tropical cyclone(TC) is derived from the continuity equation. It is found that the isentropic surfaces coincide with the streamlines, and the streamfunction can be expressed with saturated moist entropy. The secondary circulation and the saturated moist entropy structure depend on each other. Thus, a method for diagnosing the secondary circulation with the structure of saturated moist entropy is proposed. The method is verified with a simulated intense idealized TC with a highly axisymmetric structure. The diagnosed secondary circulation reproduces well the moist inflow in the boundary layer and the moist updraft in the eyewall. This method facilitates secondary circulation diagnosis in theoretical or mature TCs that satisfy the adiabatic, axisymmetric and steady approximations.

The South China Sea thermohaline structure and circulation

In this study, we used the Navy' s Master Oceanographic Observation Data Set(MOODS), consisting of 116019 temperature and 9617 salinity profiles, during 1968-1984 to investigate the temporal and spatial variabilities of South China Sea thermohaline structures and circulation. For temperature, profiles were binned into 204 monthly data sets from 1968 to 1984 (17 years). For salinity, profiles were binned into 12 climatological monthly data sets due to the data paucity. A two-scale optimal interpolation method was used to establish a three-dimensional monthly-varying gridded data set from MOODS, covering the area of 5°-25°N and 105° - 125°E and the depth from the surface to 400 m. After the gridded data set had been established, both composite analysis and the Empirical Orthogonal Function (EOF) analysis (for temperature only) were used to identify the major thermohaline fratures including annual mean, monthly anomalies, and interannual thermal variabilities. The inverted monthly circulation pattern using the P - vector method is also discussed.

A STUDY ON THE BAROCLINIC STRUCTURE OF THE ABYSSAL CIRCULATION

In this paper, the linear continuously stratified model of the abyssal circulation proposed by Pedlosky (1992) was extended to include the second order term -(γθ zzz ) in the vertical turbulent mixing parameterization of - (w′θ′) z=k υθ zz -γθ zzz , in which k υ is a vertical diffusion coefficient, and γ is the second order coefficient of turbulent mixing (or simply called γ term and γ<0 is only allowed). The influence of the γ term on the baroclinic structure of the abyssal circulation driven by upwelling out of the abyss was investigated. It was found that the γ term has a noticeable influence on the baroclinic structure of the upwelling driven abyssal circulation. For uniform upwelling, it favors the baroclinic layering of the abyssal circulation in the eastern part of the basin, but prevents the layering in the west. In addition, this parameter was found to decrease the vertically averaging meridional velocity of the abyssal circulation from the west to the east on the southern boundary. For upwelling localized near the eastern boundary, the γ-term favors baroclinic layering of the abyssal circulation in the whole basin. Especially, on the southern boundary the γ-term could strengthen the vertically averaging meridional velocity in the west, but greatly weaken it in the east. The model presented here might be considered as an extension of the Pedlosky baroclinic model of the abyssal circulation.

Seasonal evolution of circulation and thermal structure in the Yellow Sea

In this paper, the authors used the Princeton Ocean Model (POM) to simulate the seasonal evolu- tions of circulation and thermal structure in the Yellow Sea. The simulated circulation showed that the Yellow Sea Warm Current (YSWC) was a compensation current of monsoon-driven current, and that in winter, the YSWC became stronger with depth, and could flow across the Bohai Strait in the north. Sensitivity and control- ling tests led to the following conclusions. In winter, the direction of the Yellow Sea Coastal Current in the sur- face layer was controlled partly by tide instead of wind. In summer, a cyclonic horizontal gyre existed in the middle and eastern parts of the Yellow Sea below 10 m. The downwelling in upper layer and upwelling in lower layer were somehow similar to Hu et al. (1991) conceptual model. The calculated thermal structure showed an obvious northward extending YSWC tongue in winter, its position and coverage of the Yellow Sea Cold Water Mass in summer.

Simultaneous optimization and control for polypropylene grade transition with two-layer hierarchical structure

In this paper,a two-layer hierarchical structure of optimization and control for polypropylene grade transition was raised to overcome process uncertain disturbances that led to the large deviation between the open-loop reference trajectory and the actual process.In the upper layer,the variant time scale based control vector parametric methods(VTS-CVP) was used for dynamic optimization of transition reference trajectory,while nonlinear model predictive controller(NMPC) based on closed-loop subspace and piece-wise linear(SSARX-PWL) model in the lower layer was tracking to the reference trajectory from the upper layer for overcoming high-frequency disturbances.Besides,mechanism about trajectory deviation detection and optimal trajectory updating online were introduced to ensure a smooth transition for the entire process.The proposed method was validated with the real data from an industrial double-loop propylene polymerization reaction process with developed dynamic mechanism mathematical model.

Hydrographic structure and circulation in the central area of the North Eastern Atlantic

-On the basis of the hydrographic data observed within the Canary Basin in autumn 1985, temperature-salinity properties, distributions of water masses and barocltne flow field, as well as the volume transports in this area are described more detailly. The analyses indicate that the activity in the waters of the Canary Basin is mainly attributed to the interleaving and mixing between the originated water masses (e. g. Surface Water, North Atlantic Central Water, Mediterranean Water and Deep Water) and the modified water masses (Subpolar Mode Water, Labrador Sea Water and Antarctic Intermediate Water) from the outside of the study area and the variation of themselves. The east recirculation of the Subtropic Gyre in the North Atlantic consists of Azores Current and Canary Current.Azores Current is formed with several flow branches around the Azores Island, while the main flow lies at 35?N south of the Azores Island. It begins to diverge near the 15?W. The return flow found off the Portugal coast may be its northern branch. The southern invasion of the Labrador Sea Water and the Subpolar Mode Water are prevented by Azores front which serves an obvious boundary separating the North Western Atlantic (Central) Water and the North Eastern Atlantic (Central) Water.

Structural failure mechanism and strengthening method of fracture plugging zone for lost circulation control in deep naturally fractured reservoirs

Focused on the lost circulation control in deep naturally fractured reservoirs, the multiscale structure of fracture plugging zone is proposed based on the theory of granular matter mechanics, and the structural failure pattern of plugging zone is developed to reveal the plugging zone failure mechanisms in deep, high temperature, high pressure, and high in-situ stress environment. Based on the fracture plugging zone strength model, key performance parameters are determined for the optimal selection of loss control material(LCM). Laboratory fracture plugging experiments with new LCM are carried out to evaluate the effect of the key performance parameters of LCM on fracture plugging quality. LCM selection strategy for fractured reservoirs is developed. The results show that the force chain formed by LCMs determines the pressure stabilization of macro-scale fracture plugging zone. Friction failure and shear failure are the two major failure patterns of fracture plugging zone. The strength of force chain depends on the performance of micro-scale LCM, and the LCM key performance parameters include particle size distribution, fiber aspect ratio, friction coefficient, compressive strength, soluble ability and high temperature resistance. Results of lab experiments and field test show that lost circulation control quality can be effectively improved with the optimal material selection based on the extracted key performance parameters of LCMs.

ON DECENTRALIZED STABILIZATION OF LINEAR LARGE SCALE SYSTEMS WITH SYMMETRIC CIRCULANT STRUCTURE

The decentralized stabilization of continuous and discrete linear large scale systems with symmetric circulant structure was studied.A few sufficient conditions on decentralized stabilization of such systems were proposed.For the continuous systems,by introducing a concept called the magnitude of interconnected structure,a very important property that the decentralized stabilization of such systems is fully determined by the structure of each isolated subsystem that is obtained when the magnitude of interconnected structure of the overall system is given.So the decentralized stabilization of such systems can be got by only appropriately designing or modifying the structure of each isolated subsystem,no matter how complicated the interconnected structure of the overall system is.A algorithm for obtaining decentralized state feedback to stabilize the overall system is given.The discrete systems were also discussed.The results show that there is a great dfference on decentralized stabilization between continuous case and discrete case.

Circulation system complex networks and teleconnections

In terms of the characteristic topology parameters of climate complex networks, the spatial connection structural complexity of the circulation system and the influence of four teleconnection patterns are quantitatively described. Results of node degrees for the Northern Hemisphere （NH） mid-high latitude （30° N-90°N） circulation system （NHS） networks with and without the Arctic Oscillations （AO）, the North Atlantic Oscillations （NAO） and the Pacific-North American pattern （PNA） demonstrate that the teleconnections greatly shorten the mean shortest path length of the networks, thus being advantageous to the rapid transfer of local fluctuation information over the network and to the stability of the NHS. The impact of the AO on the NHS connection structure is most important and the impact of the NAO is the next important. The PNA is a relatively independent teleconnection, and its role in the NHS is mainly manifested in the connection between the NHS and the tropical circulation system （TRS）. As to the Southern Hemisphere mid-high latitude （30°S-90°S） circulation system （SHS）, the impact of the Antarctic Arctic Oscillations （AAO） on the structural stability of the system is most important. In addition, there might be a stable correlation dipole （AACD） in the SHS, which also has important influence on the structure of the SHS networks.

A parameterization scheme of vertical mixing due to inertial internal wave breaking in the ocean general circulation model

Based on the theoretical spectral model of inertial internal wave breaking （fine structure） proposed previ- ously, in which the effects of the horizontal Coriolis frequency component f-tilde on a potential isopycnal are taken into account, a parameterization scheme of vertical mixing in the stably stratified interior be- low the surface mixed layer in the ocean general circulation model （OGCM） is put forward preliminarily in this paper. Besides turbulence, the impact of sub-mesoscale oceanic processes （including inertial internal wave breaking product） on oceanic interior mixing is emphasized. We suggest that adding the inertial inter- hal wave breaking mixing scheme （F-scheme for short） put forward in this paper to the turbulence mixing scheme of Canuto et al. （T-scheme for short） in the OGCM, except the region from 15°S to 15°N. The numeri- cal results ofF-scheme by usingWOA09 data and an OGCM （LICOM, LASG/IAP climate system ocean model） over the global ocean are given. A notable improvement in the simulation of salinity and temperature over the global ocean is attained by using T-scheme adding F-scheme, especially in the mid- and high-latitude regions in the simulation of the intermediate water and deep water. We conjecture that the inertial internal wave breaking mixing and inertial forcing of wind might be one of important mechanisms maintaining the ventilation process. The modeling strength of the Atlantic meridional overturning circulation （AMOC） by using T-scheme adding F-scheme may be more reasonable than that by using T-scheme alone, though the physical processes need to be further studied, and the overflow parameterization needs to be incorporated. A shortcoming in F-scheme is that in this paper the error of simulated salinity and temperature by using T-scheme adding F-scheme is larger than that by using T-scheme alone in the subsurface layer.

Effect of the structure of ginsenosides on the in vivo fate of their liposomes

To utilize themultiple functions and give full play of ginsenosides,a variety of ginsenosides with different structures were prepared into liposomes and evaluated for their effect on the stability,pharmacokinetics and tumor targeting capability of liposomes.The results showed that the position and number of glycosyl groups of ginsenosides have significant effect on the in vitro and in vivo properties of their liposomes.The pharmacokinetics of ginsenosides liposomes indicated that the C-3 sugar group of ginsenosides is beneficial to their liposomes for longer circulation in vivo.The C-3 and C-6 glycosyls can enhance the uptake of their liposomes by 4T1 cells,and the glycosyls at C-3 position can enhance the tumor active targeting ability significantly,based on the specific binding capacity to Glut 1 expressed on the surface of 4T1 cells.According to the results in the study,ginsenoside Rg3 and ginsenoside Rh2 are potential for exploiting novel liposomes because of their cholesterol substitution,long blood circulation and tumor targeting capabilities.The results provide a theoretical basis for further development of ginsenoside based liposome delivery systems.

Abyssal Circulation in the Philippine Sea

The abyssal circulation in the Philippine Sea(PS)is investigated,with outputs from the Simple Ocean Data Assimilation version 2.2.4(SODA224).The deep-water currents in SODA224 are carefully evaluated,with sparse in situ observations in the North Pacific Ocean.In the upper deep layer(20003000 m)of the PS,a strong westward current,which originates from the Northeast Pacific Basin and enters the PS through the Yap-Mariana Junction,exists along 1114 N.This strong westward current bifurcates into two western boundary currents off the Philippines.The northward-flowing current flows out of the PS around 2021 N,whereas the southward-flowing current transports deep water from the northern hemisphere to the southern hemisphere.In the lower deep layer(30004500 m),the inflow water first flows northward to the east of the Western Mariana Basin and then turns westward at approximately 18 N.The inflow water mainly enters the Philippine Basin(PB),with a small part turning southward to constitute a weak cyclonic circulation.The water entering the PB mainly merges into a strong southward western boundary current in the south-ern PB.In the bottom layer(below 4500 m),both the northeast and northwest PB show single cyclonic gyres,whereas the south PB shows a single anticyclonic gyre.Moreover,comparisons with the observations indicate the possible existence of a cyclonic sense of circulation over the Philippine Trench.The current study provides the implications for future observations,which are needed to fur-ther investigate the temporospatial variations of the abyssal circulation in the PS on multiple scales.

Critical Time Span and Nonlinear Action Structure of Climatic Atmosphere and Ocean

This paper studies the critical time span and the approximate nonlinear action structure of climatic atmosphere and ocean. The critical time span of the climatic atmosphere and ocean, which is related to the spatial resolution required, the strength of nonlinear action, and the calculation exactness, may represent the relative temporal scale of predictability. As far as the same characteristic spatial scale is concerned, the minimum critical time span of the ocean is about 9 times of that of atmosphere, several days or more. Usually, the stronger the nonlinear action, the shorter the critical time span with smooth changes of external forces. The approximate structure of nonlinear action of climatic atmosphere and ocean is: the nonlinear action decreases usually with increasing latitude, which is related to the role of the Coriolis force in fluid motion (forming geostrophic current); the nonlinear action changes with the anomalous cyclonic or anticyclonic circulation shear, for instance, when the strength of anomalous eastward zonal circulation is comparable to that of anomalous meridional circulation, the nonlinear action is the strongest; wind stress plus gradient forces enhance the nonlinear action, etc.

THE EARLY SUMMER FLOOD PERIODS OF SOUTHERN CHINA AND THE SUMMER MONSOON CIRCULATION OF EAST ASIA

Based on the thermodynamic characteristics of the summer monsoon and foe change of the lower layer wind fields, the relation between the early summer flood periods of southern China, Including the first flood period of South China and the plum rains period of the middle-lower reaches of the Yangtze River and the activities of the summer monsoon is analysed. The establishment processes of the summer monsoon circulation of East Asia are investigated. It is shown that the beginning and ending of the flood periods are exactly in accordance with the arrival and departure of the fore boundary of the summer monsoon. The establishment process of the circulation from the very beginning of the arrival of the monsoon to the time of great prosperity of development are not the same for each year. They can be classified into four categories. Each category may have four or three stages. Besides, the structure of the summer monsoon regime of East Asia is not unitary. There exist four types of structure model of the monsoon regime of East Asia.

Development of experimental apparatus about reverse circulation bit

A set of experimental apparatus on reverse circulation bit are developed, in order to lucubrate the mechanism of the new type reverse circulation bits, and the structure of the bits influencing the ability of taking core and carrying powder.Both the major structure of the equipment and the procession of experiment are described.