Baja California 边缘PC14 岩芯海水表层温度及生产力变化的百年尺度记录

加利福尼亚流是北太平洋环流的重要组成部分,它的变化对全球气候及碳循环有重要影响.对位于东北太平洋低纬区BajaCalifornia外海的PC14柱状样进行了有机地球化学分析,重建了过去14ka来这一地区百年尺度的海水表面温度及生产力变化,发现其存在明显的B/A(Bling-Aller)和YD(Younger Drays)事件,但B/A和YD事件温度变化幅度小于中纬度地区.与中纬度加利福尼亚流系早中全新世温度降低不同,PC14全新世温度无明显变化趋势.这些结果表明了东太平洋低纬地区对高纬地区的气候响应以及沿岸上升流和ENSO现象对加利福尼亚流系中纬和低纬地区的影响不同.从冰消期到全新世,PC14生产力呈现阶段上升趋势,指示了由E1 Nino气候向La Nifia气候的转化以及沿岸上升流加强的总体趋势.在全新世中后期(6.5-3.8ka)生产力的降低,则可能是受ENSO加强的影响.在B/A暖期,PC14生产力增加不多,但氧最小层强度增加,这表明生产力变化不是东太平洋边缘海的氧最小层强化的控制因素.     

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.     

Improvement in the calculation of anti-Stokes energy transfer and experimental justification based on Er0.01YbxY1 - 0.01 - xVO4 crystal

The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{ΔE / kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er_0.01Yb_xY_{1 - 0.01 - x}VO₄ crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time.     

Diurnal SST warming in the Bay of Biscay: satellite measurements and model prediction

INTRODUCTIONIt has long been recognized that a diurnal thermal cycle occurs in the upper layer of the ocean(Stommel et al., 1969; Price and Weller, 1986). Interest in the subject has revived in recentyears due to the importance of resolving the diurnal cycle for correctly coupling the ocean and atmosphere (Lukas, 1991 ). While the study of the diurnal cycle is of intrinsic scientific interest, italso offers the benefit to remote sensing scientists of identifying the bias caused by the di…     

Study on topographic compensation model of the Okinawa Trough I. Calculation of theoretical isostatic response function

INTRODUCTIONTo study the compensation model of sea topography and isostatic states by using toPOgraphicand gravity data, is an imPOrtant mean for further researching deep structures as elastic structure,stress state of lithosphere, and so on. Since Airy and Pratt proPOsed local isostatic model in the1850' s, greater development on the theoretical study has been attained. Veining Meinesz (1941 )introduced regional compensation mechanism by considering it as floating crust in elastic fie…     

国际海道测量标准

一、背景 国际海道测量局(IHB)成立于1921年,与此同时国际海道测量组织(IHO)也应运而生,主要致力于海道测量数据采集与海图出版的规范化工作。1970年9月,当时的成员国代表正式投票通过决议,开始采用国际海道测量组织这一名称,而国际海道测量局只是其设在摩纳     

锦州湾沾污沉积物急性毒性的海洋端足类检验

１９９２年９月￣１９９３年１月对锦州湾沾污沉积物的海洋端足类急性毒性效应进行了研究。从锦州湾湾顶到湾口沿西南－－东北方向每２ｋｍ等距离采集２７个表层沉积我校 品,应用海洋端足类Ａ ｍｐｅｌｉｓｃａ ａｂｄｉｔａ对这些样品进行了１０ｄ直流式急性毒性检验,检验指标为死亡率。结果表明,五里河河口处受试生物死亡率最高,为１００％,从湾顶该河口处沿东北方向随着距离增加,死亡率逐渐递减,笔架山处最低,仅为２．     

Dispersal of the Zhujiang River (Pearl River) derived sediment in the Holocene

High-resolution Chirp profiling and coring reveals an elongated(ca. 400 km) Holocene Zhujiang River(Pearl River)-derived mud area(maximum thickness 20 m) extending from the Zhujiang River Delta, southwestward off the Guangdong coast, to the Leizhou Peninsula. Two depo-centers, one proximal and one distal, are identified. On the continental shelf off the west Guangdong Province, the mud is deposited in water depth shallower than 50 m; while to the southeast of the Zhujiang River Estuary, the mud area can extend to the-120 m isobath. A combined analysis with the stratigraphic sequences of other muddy deposits in the Western Pacific marginal seas(mainly Changjiang(Yangtze) and Huanghe(Yellow) Rivers derived) indicates that the initiation of the Zhujiang River muddy deposit can be further divided into two stages: Stage 1 is before the mid-Holocene sea-level highstand(ca. 7.0 cal. ka BP), the proximal mud was mostly deposited after 9.0 cal. ka BP, when the sea-level rose slowly after the Meltwater Pulse-1C; Stage 2, after the mid-Holocene sealevel highstand, clinoform developed on the continental shelf off the west Guangdong Province, extending ca. 400 km from the Zhujiang River Estuary. The proximal clinoform thins offshore, from ca. 10 m thickness around 5–10 m water depth to less than 1–2 m around 20–30 m water depth. In addition, we also find a developed distal clinoform in the east of the Leizhou Peninsula.     

Analysis of EMD algorithm for identification and extraction of an acoustic signal in underwater channel against wind driven ambient noise

Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, the application of Empirical Mode Decomposition （EMD） technique to analyze nonlinear and non-stationary signals has gained much attention. It is an empirical approach to decompose a signal into a set of oscillatory modes known as intrinsic mode functions （IMFs）. In general, Hilbert transform is used in EMD for the identification of oscillatory signals. In this paper anew EMD algorithm is proposed using FFT to identify and extract the acoustic signals available in the underwater channel that are corrupted due to various ambient noises over a range of 100 Hz to 10 kHz in a shallow water region.Data for analysis are collected at a depth of 5 m and 10 m offshore Chennai at the Bay of Bengal. The algorithm is validated for different sets of known and unknown reference signals. It is observed that the proposed EMD algorithmidentifies and extracts the reference signals against various ambient noises. Significant SNR improvement is alsoachieved for underwater acoustic signals.     

Submarine groundwater discharge and benthic biogeochemical zonation in the Huanghe River Estuary

Submarine groundwater discharge(SGD) has received increasing attention by studies on coastal areas; however,its effects on biogeochemical zonation have not been investigated to date. The Huanghe River Estuary(HRE) is a world class river estuary with high turbidity, and heavy human regulation. This study investigated how SGD is related to the benthic biogeochemistry of the HRE. Based on the distribution of several parameters(e.g., salinity,temperature, dissolved oxygen(DO) levels, p H, radium iso...