On one possibility of studying the cyclonic regime

The dynamics of some characteristics of a cyclonic situation (cyclonic regime) of the northwestern Pacific cyclonic zone is studied. The characteristics that are considered are the density of cyclonic energy at a point (intensity) and the power over a given area. In the model, the intensity at a point is defined as the sum of all intensities of preceding cyclones, with consideration for their spatial and temporal separation from the given point. Power for a given moment and a given area is defined as the sum of intensities over this area. Cyclonically active seasons are considered. The dynamics of the power was estimated for areas of different size. It is shown that the point values of cyclonic intensity, at the times of their maximum, are statistically related to one another by a negative power-law dependence. Periodicity is observed in the time evolution of the power in different areas.     

Energy Exchange between Jets of the Antarctic Circumpolar Current and Synoptic Eddies in the Drake Passage and Scotia Sea

We study the energy exchange between jets of the Antarctic Circumpolar Current (ACC) and synoptic eddies generated by them in the surface layer of the ocean in the Drake Passage and Scotia Sea based on 22-year-long satellite altimetry time series from the French CLS Agency (DT Global–MADT–Upd product, http://www.aviso.altimetry.fr) under the assumption, based on observations, that each of the jets is confined between two fixed contour lines of the absolute dynamic topography of the ocean. We calculate and analyze the 22-year evolution of the kinetic energy of each ACC jet and cyclonic and anticyclonic eddies generated by it. We demonstrate the fundamental dependence of fluctuations in jet energy on the phase of their meander and eddy formation, as well as their back absorption by jets. We calculate the mean and extreme energetic characteristics of jets and eddies and compare the jets in terms of the intensity of the generated eddies.     

Some interrelations between the stages of development of tropical cyclones

Energy interdependence between groups of tropical cyclones separated by time intervals of cyclonic “calm” is investigated. A linear negative interrelation between the total powers of such groups is revealed. The groups consist of real tropical cyclones that occurred within the active cyclonic zone in the northwestern Pacific. The corresponding regression relationships are obtained. Interrelation between the stages of development of seasonal cyclonic activity is revealed. Semidiurnal total powers (power elements) are chosen as “operational” objects with the use of which the sought-for interrelation is established. Regressions were obtained separately for each season: the number of elements and their powers are related by a negative power relation. The result obtained is supposed to serve as a certain basis for the probabilistic prediction of cyclonic activity during the season.     

Topographic effect of a marine ridge on the spin-down of a cyclonic eddy with mean flow

The topographic effect of a meridional marine ridge on the spin-down of a cyclonic eddy, which is embedded in a zonal mean flow, is examined by use of a two layer numerical model. It is shown that the cyclonic eddy initially given on the eastern flank of the marine ridge decays in a short time. This result is common to all cases with the different volume transports of the mean flow (3070 Sv) and of the cyclonic eddy (1535 Sv). During the decay process, the cyclonic eddy shifts mainly northward into the shallower region, which is different from the dominant westward shift of the isolated cyclonic eddy. If the mean flow across over the marine ridge at the more northern latitude, the cyclonic eddy spins down more rapidly. A mean flow shifts zonal or south-eastward over a western side of the ridge, while it deflects north-eastward over an eastern side. The deflection angle of mean flow over the ridge depends on the intensity of lower layer velocity and density stratification. It is suggested that the topographic effect of the meridional marine ridge on the cyclonic eddy with mean flow is influenced both by the global phenomena that controls the inclination of the mean flow from zonal direction and by the local phenomena that controls the intensity of the topographic effect of the marine ridge.     

Hydrographic characteristics and its variation of the South China Sea before and after monsoon burst in 1998

The differences of temperature, salinity distribution characteristics and structure of circulation in the upper layer of the South China Sea (SCS) are analyzed, based on the CTD and ADCP data from the two intensive surveyed cruises (IOP1: April 10 - May 5; IOP2: June 12 - July 6) and carried out before and after the Asian monsoon burst (May 25) during the South China Sea Monsoon Experiment (SCSMEX) in 1998. The results showed that field of temperature in the upper layer of the SCS distinctly changed before and after the monsoon burst, the average surface temperature increased by 0.75℃, with its influence down to the depth of 500 m. The interaction of the local circulation in some areas resulted in the complexity and variability of the temperature and salinity structure in the upper layer, and the alternating distribution of cold and warm water regions (blocks). The high salinity subsurface water obviously intruded into the SCS from the Northwest Pacific, but only limited to the area of southwest of Taiw     

槽道湍流的展向振荡电磁力壁面减阻

采用直接数值模拟方法,对槽道湍流的展向振荡电磁力的减阻效果和减阻机理进行了研究,讨论了电磁力强度和振荡频率对湍流猝发事件以及壁面减阻率的影响.结果表明,电磁力强度或振荡频率变化时,湍流猝发频率和猝发强度的变化趋势是相反的,所以存在最优参数使得减阻效果最好.等价壁面展向速度可以很好地描述电磁力强度和振荡频率的变化对减阻效果的综合效应.     

黑潮延伸体邻近区域中尺度涡特征统计分析

本文利用20年的卫星高度计资料,对黑潮延伸体邻近海区(25°—45°N,135°E—175°W)中尺度涡的统计特征以及季节变化进行了统计研究。基于涡旋自动识别方法,共识别出本区域3006个气旋涡轨迹和2887个反气旋涡轨迹,其平均周期分别为9.99周和11.00周,平均半径分别为69.5km和71.8km。长生命周期涡旋的平均半径、涡度、涡动能(EKE)和涡旋能量密度(EI)在生命周期内大致都经历了增大-基本保持不变-减小这三个阶段。绝大多数涡旋沿纬线向西移动,经向移动距离较小,气旋涡和反气旋涡在西向传播过程中都具有明显的向南(赤道)偏离趋势。涡旋的生成数量与总数量均在春夏季达到最多,且这一时期涡旋的平均涡度、EKE、EI处于较高水平。     

Variant for estimating the activity of tropical cyclone groups in the world ocean

Izvestiya, Atmospheric and Oceanic Physics - It is especially important to know the character and the intensity level of tropical cyclone (TC) activity when the system for estimating the cyclonic...     

Estimates for regression relationships between characteristics of tropical cyclones and gravity anomalies

We have obtained regression relationships between vertical components of gravity anomalies in tropical cyclone areas and some cyclonic characteristics. These regressions are more pronounced in territories where negative gravity anomalies are prevalent. Numerical experiments are performed for the cyclonic zone of the northwestern Pacific and western Atlantic. In the zone of the western Atlantic, the main focus is on cyclones entering to the terrestrial part of the United States. We conclude that under some conditions, gravity anomalies can affect the characteristics of tropical cyclones.     

Numerical study on the interactions between a mesoscale eddy and a western boundary current

A reduced-gravity primitive equation eddy resolving model has been used to study the decay of a mesoscale eddy as it migrates toward a western boundary current (WBC) region. The model results indicated that the gradient of the relative vorticity to the east of the WBC is an important factor in the interaction between an eddy and a WBC. A circular eddy is deformed into an elliptical form during the eddy–WBC interaction with the major axis of a cyclonic/anticyclonic eddy aligning in the NW/NNE direction, respectively. Because of the difference in the major axes orientations for the cyclonic and anticyclonic eddies, the kinetic energy transfer between a WBC and a particular eddy has very different behavior. A cyclonic eddy loses its energy to the mean field, whereas an anticyclonic eddy can obtain energy from the mean flow during the WBC–eddy interaction. An anticyclonic eddy, however, still decayed from losing its water and friction dissipation during the interaction period.     

南印度洋中尺度涡统计特征及三维合成结构研究

南印度洋是海洋中尺度涡的多发区域。本文利用卫星高度计资料及Argo浮标资料,对南印度洋（10°~35°S, 50°~120°E）区域中尺度涡的分布、表观特征等进行了统计分析,采用合成方法,构建了该区域中尺度涡的三维温盐结构。结果表明,涡旋频率呈明显的纬向带状分布,在18°~30°S存在一个明显的涡旋频率带状高值区;涡旋半径具有由南至北逐渐增大的趋势;长周期涡旋在其生命周期内,半径、涡动能、涡能量密度、涡度等性质均经历了先增大而后减小的过程;涡旋以西向运动为主,在经向上移动距离较小,长周期气旋（反气旋）涡具有明显的偏向极地（赤道）移动的倾向;涡旋平均移动速度为5.9 cm/s,速度大小大致沿纬向呈带状分布。在混合层以下,气旋涡（反气旋涡）内部分别呈现明显的温度负（正）异常,且分别存在两个位温负（正）异常的冷（暖）核结构;气旋涡（反气旋涡）整体上呈现"正-负"（"负-正"）上下层相反的盐度异常结构。中尺度涡对温盐的平均影响深度可达1 000×104 Pa以上。     

Mutual Dynamics of Tropical Cyclones

Izvestiya, Atmospheric and Oceanic Physics - Interrelations of an energy nature in the dynamics of cyclonic activity of tropical cyclones (TCs) are considered. The relationships, represented by...     

Exact solution of phantom dark energy model

We investigate the phantom dark energy model derived from the scalar field with a negative kinetic term. By assuming a particular relation between the time derivative of the phantom field and the Hubble function, an exact solution of the model is constructed. Absence of the `big rip' singularity is shown explicitly. We then derive special features of phantom dark energy model and show that its predictions are consistent with all astrophysical observations.     

Long-term tendencies in the variability of characteristics of the Black Sea pycnocline

The rise of the waters of the main pycnocline in the central part of the western cyclonic gyre at the end of the winter in the 1960s–1970s and their deepening in the eastern cyclonic gyre from the mid-1960s to the late 1980s were revealed on the basis of archival hydrologic data obtained on the standard sections of the Black Sea in 1957–1992. It is shown that, simultaneously, the waters of the pycnocline descended in the Sevastopol anticyclone and rose in the Yalta and Batumi anticyclones. These tendencies indicate that the water circulation intensified in the region of the western cyclonic gyre (off the southwestern coast of the Crimea) and weakened in the vicinity of the eastern cyclonic gyre at the end of the winter season in the 1960s–1970s and in the 1960s–1980s, respectively. It is shown on the basis of NCEP reanalysis data and archival hydrometeorological data that all major circulation factors, such as a decrease in the cyclonic vorticity in the wind field during the winter season, changes in its spatial structure, an increase in the river discharge, and a decrease in the turbulent heat fluxes at the Black Sea surface, affect the energy redistribution between the gyres. The role of each of these factors is analyzed.     

中国近海及其附近海域若干涡旋研究综述Ⅱ.东海和琉球群岛以东海域

综述东海和琉球群岛以东海域若干气旋型和反气旋型涡旋的研究.对东海陆架、200m以浅海域,主要讨论了东海西南部反气旋涡、济州岛西南气旋式涡和长江口东北气旋式冷涡.东海两侧和陆坡附近出现了各种不同尺度的涡旋,其动力原因之一是与东海黑潮弯曲现象有很大关系,其次也与地形、琉球群岛存在等有关.东海黑潮有两种类型弯曲:黑潮锋弯曲和黑潮路径弯曲.黑潮第一种弯曲出现了锋面涡旋,评述了锋面涡旋的存在时间尺度与空间尺度和结构等;也指出了黑潮第二种弯曲,即路径弯曲时在其两侧出现了中尺度气旋式和反气旋涡,讨论了它们的变化的特性.特别讨论了冲绳北段黑潮弯曲路径和中尺度涡的相互作用,着重指出,当气旋式涡在冲绳海槽北段成长,并充分地发展,其周期约在1~3个月时,它的空间尺度成长到约为200km(此尺度相当于冲绳海槽的纬向尺度)时,黑潮路径从北段转移到南段.也分析了东海黑潮流量和其附近中尺度涡的相互作用.最后指出在琉球群岛以东、以南海域,经常出现各种不同的中尺度反气旋式和气旋式涡,讨论了它们在时间与空间尺度上变化的特征.     

The influence of mesoscale physical processes on the larval fish community in the Canaries CTZ, in summer

We have studied the relation between the hydrography, the composition and horizontal structure of the larval fish community, and the horizontal distribution patterns of larval fish abundances in an area characterised by strong mesoscale oceanographic activity, located between the Canary Islands and the African coast (the Canaries Coastal Transition Zone), during August 1999. Upwelling, upwelling filaments, cyclonic and anticyclonic eddies and island wakes are typical mesoscale features of the northwest African coast in summer. A single upwelling filament off Cabo Juby was joined in mid-August by a second that originated about 100 km to the north. The two filaments flowed together and merged 100 km offshore. The merged filament was partially entrained around a cyclonic eddy, trapped between the Canary Islands and the African coast, and interacted with cyclonic and anticyclonic eddies shed from Gran Canaria. Mesoscale oceanographic features strongly influenced the horizontal distributions of fish larvae. Eddies acted as a mechanism of concentration, while upwelling filaments were dispersive, transporting larvae from the African neritic zone into oceanic areas and towards the Canary archipelago. This transport was the major cause of the predominance of neritic larvae in the composition of the larval fish community of the area. The results also suggest: (1) that anchovy larvae are good indicators of the offshore displacement of upwelled water; (2) that the alternation between anchovy and sardine as species dominant in the larval fish community of the area during summer depends upon the water temperature in the African upwelling region, anchovy dominating at higher temperature; (3) that a coupling of anchovy and sardine spawning with the mesoscale oceanographic structure formed by the upwelling filaments and trapped eddy overcomes the negative effect that Ekman transport has on their populations.     

硅的间接跃迁双光子吸收系数谱

利用皮秒Nd:YAG脉冲激光器作为激发光源,测量出光子能量介于1.36 μm (0.912 eV)—1.80 μm (0.689 eV)之间的硅间接跃迁双光子吸收系数谱.尽管此波段范围内的激光光子能量小于硅间接带隙,但当激光辐照在硅基光电二极管受光面时,在二极管两电极端仍然探测到了显著的脉冲光伏信号.光伏信号峰值强度与入射光强呈二次幂函数关系,表明其是双光子吸收过程.采用pn结等效结电容充放电模型,将光伏响应信号峰值与入射光强相关联,从中提取出硅的间接跃迁双光子吸收系数,改变入射波长得到系数谱.研究表明:     

Mesoscale eddies off Peru in altimeter records: Identification algorithms and eddy spatio-temporal patterns

Relatively little is known about coherent vortices in the eastern South-Pacific along the Peruvian coast, even with regard to basic facts about their frequency of occurrence, longevity and structure. This study addresses these issues with nearly 15 years of relatively high-resolution satellite altimetry measurements.We first compare two distinct automated methods for eddy identification. The objective validation protocol shows that the rarely-used geometrical or “winding-angle method”, based on the curvature of the streamline functions, is more accurate than the commonly-used “Okubo–Weiss algorithm”, which defines a vortex as a simple connected region with values of Okubo–Weiss parameter weaker than a given threshold.We then investigate vortices off Peru using more than 20,000 mesoscale eddies identified by the winding-angle method. Coherent eddies, characterized by a high ratio of vorticity to deformation rate, are typically formed along the coast and propagate westward at 3–6 cm s⁻¹. The vortices have a mean radius of 80 km, increasing northward, and are most frequently observed off of Chimbote (9°S) and south of San Juan (15°S). The mean eddy lifetime is about 1 month, but if eddies survive at least 2 months, the probability for surviving an additional week (or month) is constant at 90% (or 67%). Anticyclonic eddies tend to propagate northwestward whereas cyclonic vortices migrate southwestward. In general, cyclones and anticyclones are similar, except for eddies surviving at least 6 months. In this case, after a similar 3–4 months of radius and amplitude growth, amplitudes (or sizes) decay particularly rapidly for anticyclonic (or cyclonic) eddies. In terms of intensity, cyclonic eddies show a rapid decay during the first 3 months before arriving at a quasi-constant value, whereas anticyclones exhibit steady decline. Finally, eddy temporal variations were examined at seasonal and interannual scales in the “coastal” region favorable to the formation of energetic mesoscale structures. On seasonal scales, eddy activity is maximal in fall and minimum in spring. At interannual scales, the eddy activity index was maximal during the strong El Niño of 1997–1998 but another strong maximum of eddy activity also occurred late in 2004. These temporal variations are probably associated with the intensification of the upwelling thermal front and with the passage of coastal-trapped waves which generate baroclinic instabilities. Further investigation of the mechanisms involved on the eddy genesis is needed.     

合浦珠母贝卵子电击脉冲参数的初步研究

运用电脉冲转基因仪对合浦珠母贝卵子进行电脉冲处理以优化电穿孔法转基因的电击参数。实验中调制百分比：100％；脉冲间隔：1．0s：电极距离：2mm；脉冲个数：5个，参数保持不变。用不同的电脉冲参数组合（脉冲电压100-400V、脉冲持续时间0．5～3．0ms、脉冲频率10～50kHz，共28个组合）对卵子电击，然后加入精子进行授精，统计各组受精率和孵化率，以受精率和孵化率达到50％以上为衡量指标。结果表明，合浦珠母贝卵子对低脉冲频率和高电压非常敏感，当频率低于20kHz或脉冲电压高于400V时对卵子损伤较大。脉冲持续时间对其影响不大，适应范围较宽。优化的转基因电击脉冲参教组合为：脉冲电压1.0kV／cm，脉冲持续时间20ms，脉冲频率50kHz，或者脉冲电压1．5kV／cm，脉冲持续时间1．5ms，脉冲频率50kHz。     

Cyclonic Activity of Tropical Cyclones and Its Dynamics: A Single Continuous Process

Izvestiya, Atmospheric and Oceanic Physics - The possible effect of the cyclonic activity of tropical cyclones of one year on the cyclonic activity of the next year has been investigated. The...