Evaluation of a method to reduce uncertainty in wind hindcasts performed with regional atmosphere models     

R. Weisse  F. Feser 《Coastal Engineering》2003,48(4):211-225

For more and more applications in coastal and offshore engineering, numerical simulations of waves and surges are required. An important input parameter for such simulations are wind fields. They represent one of the major sources for uncertainties in wave and surge simulations. Wind fields for such simulations are frequently obtained from numerical hindcasts with regional atmospheric models (RAMs). The skill of these atmospheric hindcasts depends, among others, on the quality of the forcing at the boundaries. Furthermore, results may vary due to uncertainties in the initial conditions. By comparing different existing approaches for forcing a regional atmospheric model, it is shown that the models' sensitivity to uncertainties in the initial conditions may be reduced when a more sophisticated approach is used that has been suggested recently. For a specific, although somewhat brief test period, it is demonstrated that an improved hindcast skill for near surface wind fields is obtained when this approach is adopted. Consequences of the reduced uncertainty in wield fields for the hindcast skill of subsequent wave modelling studies are demonstrated. Recently, this new approach has been used together with a regional atmosphere model to produce a 40-year wind hindcast for the Northeast Atlantic, the North Sea and the Baltic Sea. The hindcast is presently extended to other areas and the wind fields are used to produce 40-year high-resolution hindcasts of waves and surges for various European coastal areas.  相似文献   

Ferromanganese Nodules and their Associated Sediments from the Central Indian Ocean Basin: Rare Earth Element Geochemistry     

J. N. Pattan  Ch. M. Rao  A. A. Migdisov  S. Colley  N. C. Higgs  L. Demidenko 《Marine Georesources & Geotechnology》2001,19(3):155-165

The rare earth element (REE) distribution in nine deep-sea ferromanganese nodules and their associated siliceous sediments from the Central Indian Ocean Basin (CIOB) have been studied to elucidate the REE relationship among them. Total REE concentration varies from 398-928 ppm in the nodules and 137-235 ppm in the associated sediments, suggesting two- to four-fold enrichment in the nodules compared to associated sediments. REE of nodules and their associated sediments show a positive correlation, suggesting REE are supplied from a common source such as seawater. The positive correlation between REE of nodules and sediments from the CIOB is contrary to the competitive scavenging of REE between nodules and sediment in the equatorial Pacific Ocean. REEs in the nodules are carried by Fe, P, and Ti, whereas in the sediment they are carried by P and Mn phases. A similar REE fractionation pattern with middle REE enrichment over heavy and light REE in both the nodules and their associated sediment suggest fractionation is independent of REE abundance and their carrier phases.  相似文献   

多金属结核生长过程中元素通量的变化规律     

孙志国  刘季花  姚德  许东禹 《海洋科学进展》1996,(1)

本文主要研究太平洋ＣＣ区多金属结核ＣＣＡ３３，ＣＣＢ２９，ＣＣＣ５０，ＣＣＣ１４生长过程中锰、铁、镍、铜的通量（ＦＭｎ），ＦＦｅ，ＦＮｉ，ＦＣｕ）的变化规律．研究表明：１．结核生长过程中Ｍｎ，Ｆｅ，Ｎｉ和Ｃｕ的通量都是波动性的；２．ＦＭｎ与ＦＦｅ，ＦＮｉ，ＦＣｕ均呈正相关性；３．结核的元素通量与结核的成因类型和生长阶段密切相关，并记录了海底缺氧事件；４．结核的元素通量存在区域性差异，是沉积环境不同的反映。  相似文献   

Energetics of the Tsunami of 26 December 2004 in the Indian Ocean: A Brief Review     

N. Nirupama  T. S. Murty  I. Nistor  A. D. Rao 《Marine Geodesy》2006,29(1):39-47

The energetics of the most destructive tsunami in historical time, and that of the under ocean earthquake that triggered this tsunami of 26 December 2004 in the Indian Ocean have been briefly reviewed. This latest tsunami has several other unique characteristics besides being one of the worst natural disasters in human history. It is the first truly global tsunami after modern seismographic and sea level monitoring networks have been put in place. It was the first tsunami on record detected by a satellite, even though at present, global satellite coverage of the oceans for real time tsunami detection is not adequate. Finally, the energy associated with the tsunami and the earthquake that triggered it is so large that speculation has been made about the normal modes of oscillation of the earth, that were triggered by the earthquake as well as some suggestions, that some of the earth's rotational characteristics may have temporarily changed to a discernible degree. Here, we briefly review the energetics of the tsunami and the earthquake that triggered it.  相似文献   

Rare earth elements-rich phase and enriching mechanism in sediments from CC area, the Pacific Ocean   总被引：1，自引：0，他引：1  

Meng Xianwei  Chen Zhihu  Wang Xiangqin  Liu Na 《海洋学报(英文版)》2001,20(2):209-214

Compared to North American shale composition (NASC),REE contents of sediments from the CC area in the Pacific Ocean are obviously high except that cerium has equal content to that of NASC.Three-valence rare earth elements were completely enriched in phosphate-phase and cerium in iron-phase.Rare earth elements in the sediments were originally derived from seawater.During lithigenic and minerogenic processes of metalliferous nodules,three-valence rare earth elements in sediments mobilized and incorporated into sediments as authigenous biogenic-apatite,while cerium had change from Ce³⁺ to Ce⁴⁺ and directly precipitated from seawater and entered metalliferous nodules and caused Ceanomalies in REE pattern in sediments.  相似文献   

High resolution velocity analysis of ocean bottom seismometer data by theτ-p method     

Masanao Shinohara  Naoshi Hirata  Narumi Takahashi 《Marine Geophysical Researches》1994,16(3):185-199

A method of high resolution seismic velocity analysis for ocean bottom seismometer (OBS) records is applied to the study of the shallow oceanic crust, especially sedimentary and basement layers. This method is based on the direct-p mapping and the-sum inversion. We use data obtained from a 1989 airgun-OBS experiment in the northern Yamato Basin, Japan Sea and derive P- and S-wave velocity functions that can be compared with the seismic reflection profiles. Using split-spread profile records, we obtain interface dips and true interval velocities from the OBS data. These results show good agreement with the reflection profile records, the acoustic velocities of core samples, and sonic log profiles. We also present a method for estimating errors in the derived velocity functions by calculating covariance of the derived layers' thicknesses. The estimated depth errors are about 150 m at shallow depths, which is close to the seismic wavelength used. The high resolution of this method relies on accurate determination of shot positions by GPS, spatially dense seismic observations, and the use of unsaturated reflected waves arriving after the direct water wave that are observed on low-gain component records.  相似文献   

多系统集成的全球地球观测系统与全球海洋观测系统   总被引：3，自引：0，他引：3  

麻常雷  高艳波 《海洋技术学报》2006,25(3):41-44,50

多系统集成的全球地球观测系统(GEOO S)是一个新概念,它从更高层次上规划全球的地球观测,国际社会十分重视这一系统的建设,其关键是综合、协调、持续的地球观测系统。全球海洋观测系统(GOO S)是GEO SS的重要组成部分,是它的一个子系统。文中阐述了GEO SS的基本概念及与GOO S的关系,综述了海洋环境基本要素观测技术特别是遥感观测技术的最新进展,它也是GEOO S的基本观测手段。  相似文献   

南极沿海冷水环境中低分子挥发性脂肪酸的初步研究     

杨和福 《海洋与湖沼》1992,23(6):599-605

于1988年5月—1989年2月,对东南极Vestfold丘陵地区沿海海域水体中的低分子挥发性脂肪酸的连续测定表明,该海域海水中的低分子挥发性脂肪酸主要以甲酸、乙酸、丙酸和丙烯酸为主,其含量明显呈季节性变化。变化范围分别为:甲酸0.4—7.0μmol/L;乙酸0.1—40.0μmol/L;丙酸0.7—128.0μmol/L和丙烯酸0.001—0.393μmol/L,最高浓度出现在夏季。通过对浮游植物的观察和二甲基硫的测定,揭示低分子挥发性脂肪酸主要来自微生物作用,其中丙烯酸直接来源于棕囊藻(Phaeocystis pouchetii)细胞繁殖生长过程中的代谢作用。  相似文献   

海台及其性质的初步分析   总被引：6，自引：0，他引：6  

张抗 《海洋地质与第四纪地质》1991,11(1):1-13

本文对海台及其性质作了初步分析,它具有相对平静或非线性的磁场,一般为无震区,其地壳明显厚于大洋盆地,并具洋陆地壳间的某种过渡性.  相似文献   

南太平洋风场时空统计特征分析   总被引：2，自引：0，他引：2  

杨亮  刘金芳  张国友  闫明  尼建军 《海洋湖沼通报》2003,(2):17-23

南太平洋风场时空统计特征对船舶远洋交通运输、远洋出访、南极考察和科学试验等活动有重要实用价值。本文根据 1 950～ 1 995年共 46a的南太平洋船舶气象报资料 ,按 1°× 1°和5°× 5°网格统计的海面风进行分析研究。通过分析每月风各要素的等值线分布图 ,得出南太平洋风场季节变化特点不如北半球各大洋显著 ,但仍有较明显的季节变化 ,只是季节性差异较小 ,冬季比夏季风强盛 ,相应的平均风速 6级和 8级以上大风频率也较大 ;全年风场基本相似 ,低纬度地区 (2 5°S以北至赤道 )为信风区 ,常年盛行东至东南风 ;2 5°S～ 35°S的广大海域上 ,风力较小 ,风向变化最大 ;40°S以南盛行偏西风 ,风力最强。  相似文献