Preconditioned Optimizing Utility for Large-dimensional analyses (POpULar)     

Yosuke Fujii 《Journal of Oceanography》2005,61(1):167-181

I present the derivation of the Preconditioned Optimizing Utility for Large-dimensional analyses (POpULar), which is developed for adopting a non-diagonal background error covariance matrix in nonlinear variational analyses (i.e., analyses employing a non-quadratic cost function). POpULar is based on the idea of a linear preconditioned conjugate gradient method widely adopted in ocean data assimilation systems. POpULar uses the background error covariance matrix as a preconditioner without any decomposition of the matrix. This preconditioning accelerates the convergence. Moreover, the inverse of the matrix is not required. POpULar therefore allows us easily to handle the correlations among deviations of control variables (i.e., the variables which will be analyzed) from their background in nonlinear problems. In order to demonstrate the usefulness of POpULar, we illustrate two effects which are often neglected in studies of ocean data assimilation before. One is the effect of correlations among the deviations of control variables in an adjoint analysis. The other is the nonlinear effect of sea surface dynamic height calculation required when sea surface height observation is employed in a three-dimensional ocean analysis. As the results, these effects are not so small to neglect.  相似文献   

Summer distribution and geochemical composition of suspended-particulate matter in the east china sea     

Jia-Jang Hung  Chia-Lin Chan  Gong-Ching Gong 《Journal of Oceanography》2007,63(2):189-202

The distribution and geochemical composition of suspended-particulate matter (SPM) in the East China Sea (ECS) were investigated during the summer period of high continental runoff to elucidate SPM sources, distribution and cross-shelf transport. The spatial variability of SPM distribution (0.3–6.5 mg l⁻¹) and geochemical composition (POC, Al, Si, Fe, Mn, Ca, Mg and K) in the ECS was pronounced during summer when the continental fluxes of freshwater and terrestrial materials were highest during the year. Under the influences of Changjiang runoff, Kuroshio intrusion, surface production and bottom resuspension, the distribution generally showed strong gradients decreasing seaward for both biogenic and lithogenic materials. Particulate organic carbon was enriched in surface water (mean ∼18%) due to the influence of biological productivity, and was diluted by resuspended and/or laterally-transported materials in bottom water (mean 9.4%). The abundance of lithogenic elements (Al, Si, Fe, Mn) increased toward the bottom, and the distribution correlations were highly significant. Particulate CaCO₃ distribution provided evidence that the SPM of the bottom water in the northern part of the study area was likely mixed with sediments originally derived from Huanghe. A distinct benthic nepheloid layer (BNL) was present in all seaward transects of the ECS shelf. Sediment resuspension may be caused by tidal fluctuation and other forcing and be regarded as the principal agent in the formation of BNL. This BNL was likely responsible for the transport of biogenic and lithogenic particles across or along the ECS shelf. Total inventories of SPM, POC and PN are 46, 2.8 and 0.4 Tg, respectively, measured over the total area of 0.45 × 10⁶ km² of the ECS shelf. Their mean residence times are about 27, 13 and 11 days, respectively. The inventory of SPM in the water column was higher in the northernmost and southernmost transects and lower in the middle transects, reflecting the influences of terrestrial inputs from Changjiang and/or resuspended materials from Huanghe deposits in the north and perhaps from Minjiang and/or Taiwan’s rivers in the south. The distribution and transport patterns of SPM and geochemical elements strongly indicate that continental sources and cross-shelf transport modulate ECS particulate matter in summer.  相似文献   

Three cletodid copepods of the genera<Emphasis Type="Italic">limnocletodes</Emphasis> and<Emphasis Type="Italic">kollerua</Emphasis> (harpacticoida,cletodidae) from coastal marshes and estuaries in south Korea     

Ji Min Lee  Cheon Young Chang 《Ocean Science Journal》2007,42(4):255-267

  相似文献   

九龙江河口区磷的转移和入海通量   总被引：1，自引：3，他引：1  

陈松  廖文卓  骆炳坤  许爱玉 《台湾海峡》1996,15(2):137-142

1992～1993年4个航次的调查研究结果表明，九龙江河口区总磷的分布和转移受悬浮物含量明显控制。当SPM含量低时，其迁移过程接近理想行为；SPM含量高时则为非理想行为。估算得出，九龙江水体总磷的平均人海通量为1．47×103t／a。其中，溶解态磷为0．43×103t／a，约占29％；颗粒态磷占71％，九龙江水磷的输入以颗粒态为主。溶解态磷的分布，基本上在某一水平上了波动，其入海通量受环境影响很小，可能意味着颗粒磷的缓冲作用。  相似文献   

数据监控系统中监控软件的实现   总被引：1，自引：0，他引：1  

王文俊  罗林 《海洋技术学报》2001,20(1):35-43

本文主要介绍了国家海洋863计划中的818－01－04课题（上海海洋环境立体监测和信息服务系统）中的数据监控系统在编制中的设计思想和有关技术，数据监控系统是在广泛的对国内外的相关资料进行深入调研和学习后，根据本项目具体的要求，利用当今先进的系统设计理论和计算机软件地工程工技术进行系统功能的设计，并采用了依先的软件编程技术，完成了本课题中监控平台的制作，本系统软件主要是运用Delphi3,VC 5.0进行编制的，同时使用了SQLSVERVER6．5数据库管理系统进行后台输数据的存储管理，在数据的传输控制和数据处理过程中，系统还利用了远程数据文件传输技术FTP和互联网技术INTERNET以及拔号进行数据传输技术等，系统在近半年运动中，系统功能稳定，数据处理及时准确，同时通过了海洋863专家的鉴定，并得到同行业及用户的好评。  相似文献   

Co–rich Mn crusts from the Magellan Seamount cluster: the long journey through time     

Geoffrey P. Glasby  Xiangwen Ren  Xuefa Shi  Irina A. Pulyaeva 《Geo-Marine Letters》2007,27(5):315-323

The Magellan seamounts began forming as large submarine shield volcanoes south of the equator during the Cretaceous. These volcanoes formed as a cluster on the small Pacific plate in a period when tectonic stress was absent. Thermal subsidence of the seafloor led to sinking of these volcanoes and the formation of guyots as the seamounts crossed the equatorial South Pacific (10–0°S) sequentially and ocean surface temperatures became too high for calcareous organisms to survive. Guyot formation was completed between about 59 and 45 Ma and the guyots became phosphatized at about 39–34 and 27–21 Ma. Ferromanganese crusts began formation as proto-crusts on the seamounts and guyots of the Magellan Seamount cluster towards the end of the Cretaceous up to 55 Ma after the formation of the seamounts themselves. The chemical composition of these crusts evolved over time in a series of steps in response to changes in global climate and ocean circulation. The great thickness of these crusts (up to 15–20 cm) reflects their very long period of growth. The high Co contents of the outer parts of the crusts are a consequence of the increasing deep circulation of the ocean and the resulting deepening of the oxygen minimum zone with time. Growth of the Co-rich Mn crusts in the Magellan Seamount cluster can be considered to be the culmination of a long journey through time.  相似文献   

Estimating the geostrophic velocity obtained by HF radar observations in the upstream area of the Kuroshio     

Ryoko Tokeshi  Kaoru Ichikawa  Satoshi Fujii  Kenji Sato  Shoichiro Kojima 《Journal of Oceanography》2007,63(4):711-720

A method to extract geostrophic current in the daily mean HF radar data in the Kuroshio upstream region is established by comparison with geostrophic velocity determined from the along-track altimetry data. The estimated Ekman current in the HF velocity is 1.2% (1.5%) and 48° (38°)-clockwise rotated with respect to the daily mean wind in (outside) the Kuroshio. Furthermore, additional temporal smoothing is found necessary to remove residual ageostrophic currents such as the inertial oscillation. After removal of the ageostrophic components, the HF geostrophic velocity agrees well with that from the altimetry data with rms difference 0.14 (0.12) m/s in (outside) the Kuroshio.  相似文献   

The origin and biogeochemistry of organic matter in surface sediments of Lake Shihwa and Lake Hwaong     

Eun -Ji Won  Hyen -Goo Cho  Kyung -Hoon Shin 《Ocean Science Journal》2007,42(4):223-230

To understand the origin and biogeochemistry of the organic matter in surface sediments of Lake Shihwa and Lake Hwaong, organic nitrogen, inorganic nitrogen, labile organic carbon, and residual organic carbon contents as well as stable isotope ratios for carbon and nitrogen were determined by KOBr-KOH treatment. Ratios of organic carbon to organic nitrogen (C_org/N_org) (mean = 24) were much higher than ratios of organic carbon to total nitrogen (C_org/N_tot) (mean=12), indicating the presence of significant amounts of inorganic nitrogen in the surface sediments of both lakes. Stable isotope ratios for organic nitrogen were, on average, 5.2‰ heavier than ratios of inorganic nitrogen in Lake Shihwa, but those same ratios were comparable in Lake Hwaong. This might be due to differences in the origin or the degree of degradation of sedimentary organic matter between the two lakes. In addition, stable isotope ratios for labile organic carbon were, on average, 1.4‰ heavier than those for residual organic carbon, reflecting the preferential oxidation of¹³C-enriched organic matter. The present study demonstrates that KOBr-KOH treatment of sedimentary organic matter can provide valuable information for understanding the origin and degradation state of organic matter in marine and brackish sediments. This also suggests that the ratio of C_org/N_org and stable isotope ratios for organic nitrogen can be used as indexes of the degree of degradation of organic matter.  相似文献   

Guadalupian （Middle Permian） Conodont Faunas at Shangsi Section, Northeast Sichuan Province   总被引：1，自引：0，他引：1  

孙亚东  赖旭龙  江海水  罗根明  孙思  阎春波  PaulBWignall 《中国地质大学学报(英文版)》2008,19(5):451-460

This study recovered the Guadalupian conodont faunas from Shangsi (上寺) Section in Northeast Sichuan (四川). Four genera and nine species were identified, and three conodont zones were recognized and established; they include Jinogondolella nankingensis Zone, J. aserrata Zone, and J. postserrata Zone. The Roadian and Wordian boundary is set in the interval 5 m from the top of Bed 86 by the first appearance of the conodont J. aserrata. The Wordian and Capitanian boundary is set in the interval 2.3 m from the top of the Bed 95 by the first appearance of J. postserrata. Most of the specimens demonstrated low color alteration index (CAI) as 1.5-3, indicating that most part of the Maokou (茅口) Formation may have the suitable thermal conditions for the formation of oil source rocks.  相似文献   

改进的能量守恒方法及其在CHAMP重力场恢复中的应用(英文)   总被引：1，自引：0，他引：1  

XU Tianhe HE Kaifei Xi’an Research Institute of Surveying  Mapping  Middle Yanta Road  Xi’an  China. 《地球空间信息科学学报》2008,11(3):168-173

An efficient method for gravity field determination from CHAMP orbits and accelerometer data is referred to as the energy balance approach. A new CHAMP gravity field recovery strategy based on the improved energy balance approach IS developed in this paper. The method simultaneously solves the spherical harmonic coefficients, daily Integration constant, scale and bias parameters. Two 60 degree and order gravitational potential models, XISM-CHAMPO1S from the classical energy balance approach, and XISM-CHAMPO2S from the improved energy balance, are determined using about one year＇s worth of CHAMP kinematic orbits from TUM and accelerometer data from GFZ. Comparisons among XISM-CHAMPO1S, XISM-CHAMPO2S, EIGEN-CGO3C, EIGEN-CHAMPO3S, EIGEN2, ENIGNIS and EGM96 are made. The results show that the XISM-CHAMPO2S model is more accurate than EGM96, EIGENIS, EIGEN2 and XISM-CHAMPO1S at the same degree and order, and has almost the same accuracy as EIGEN-CHAMPO3S.  相似文献