Excursion to Bristol: Monday,August 16th,and Five Following Days     

《Proceedings of the Geologists' Association. Geologists' Association》1880,6(8):396-402

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137°经向断面温、盐度的年际变异     

顾玉荷  孙湘平  胡敦欣 《海洋学报》1999,21(6):9-16

系统地分析了137°E断面温、盐度的多年变化,主要结果为:(1)137°E断面100m层温度,在低纬度海域于某些年份出现异常低温,此现象可能与厄尔尼诺事件有关;指出棉兰老冷涡的存在是造成该断面于6°～8°N附近出现低温的主要原因。(2)厄尔尼诺期间,冬季137°E断面上28℃等温线所在纬度小于其多年平均值。(3)冬季137°E断面上次表层高盐水可划分为强型、次强型、中等型和弱型4种类型。  相似文献   

A new hypothesis about the surface circulation in the eastern basin of the mediterranean sea   总被引：3，自引：1，他引：3  

Najwa Hamad  Claude Millot  Isabelle Taupier-Letage 《Progress in Oceanography》2005,66(2-4):287

In time, the circulation of the Atlantic Water (AW) in the eastern basin of the Mediterranean Sea has been described differently, according to two major representations. The historical one, which began with the scheme from Nielsen in 1912 and has been refined up to the 1980s, favours a counterclockwise circulation in the whole basin, with AW flowing in its southern part as a broad flow off Libya and Egypt (from the Ionian to the Levantine subbasins), then continuing along Middle-East and Turkey before flowing back westwards. The more recent one, issued in the 1990s, favours a clockwise circulation in the northern part of the Ionian continuing offshore across the basin from the Cretan to the central part of the Levantine as the so-called “Mid-Mediterranean Jet”. This jet is depicted then as splitting both clockwise in the southeastern part of the basin and counterclockwise off Turkey (where this representation agrees with the former). Because the recent representation cannot be considered as a refinement of the historical ones, we have been interested in understanding why a given data set available to everybody is interpreted in such different ways.In the Algerian subbasin, the combined use of satellite infrared images and a significant amount of in situ data sets (hydrology and both Eulerian and Lagrangian current measurements) allowed us to solve a similar controversy. Therefore, we examined the circulation features in the eastern basin, undertaking the detailed analysis of 1000 daily and weekly composite images spanning the period 1996–2000, and of monthly composite images available since 1985. Whenever in situ observations were available, we have confronted them with the satellite thermal signatures and have shown that both are consistent. This paper focuses on the overall (basin scale) results while the detailed ones are published in an other paper. The new scheme we propose is basically a refined version of the historical ones: the circulation of AW is counterclockwise in the whole eastern basin but it is more constrained alongslope than previously thought, and the broadening historically schematised appears to be due to intense mesoscale eddies mainly generated by the instability of this circulation.  相似文献   

P/E界线全球事件在西藏定日地区的响应     

李祥辉  胡修棉  王成善  包向农  万晓樵  范善发 《海洋地质与第四纪地质》2002,22(1):69-74

生物群、沉积物和有机地球化学变化显示，古新统－始新统（P／E）界线全球事件在西藏南部定日（东特提期残留海低纬度浅水）地区存在明显响应：古新统宗浦组顶部有孔虫动物群的属、种绝灭率分别为87％和94％，始新统遮普惹组底部有孔虫属、种新生率分别达80％和69％；岩层以（生物滩相）薄－中层向厚层－块状生物灰岩转化，泥质含量增加；典型生物标志经合物参数变化明显，Pr／17比值平均从0．365增加到0．86，Ph／18由0．56变为0．92，β／17由12．843剧增到123．17，γ／17由2．46突变为29．5。结合西藏及邻区岩相分布、接触关系后认为，这种全球地质事件的响应在研究区可能是一种古海洋事件，可能由大洋环流（古水团）变化引起。  相似文献   

大沽河干流青岛段水环境容量研究   总被引：4，自引：1，他引：4  

张俊  佘宗莲  王成见  孙宝权 《中国海洋大学学报(自然科学版)》2003,33(5):665-670

本文根据大沽河的水流特性和水文、水质实测资料 ,利用 QUAL2 E综合水质模型 ,分析确定了大沽河干流丰水期和平水期的水环境容量。又利用水库水环境容量的计算方法 ,确定了大沽河干流枯水期的水环境容量。大沽河干流水环境容量的确定 ,可用于河流的水质模拟和预测 ,为实施大沽河污染物总量控制提供基础资料 ,为大沽河流域水污染控制的管理和决策提供科学依据  相似文献   

两种石斑鱼及其杂种子代的分子鉴定   总被引：4，自引：0，他引：4  

杜佳莹  丁少雄  王军  王世锋  庄轩  尤颖哲 《海洋学报》2006,28(6):94-99

针对在分类上存在混淆的点带石斑鱼和斜带石斑鱼,在形态学基础上,运用mtDNA Cytb基因扩增序列分析、RAPD、AFLP等分子标记技术对两种石斑鱼的遗传关系进行了研究.研究结果表明:(1)点带石斑鱼与斜带石斑鱼的分化已达到种间水平,mtDNACytb基因序列相似度为94.4%,AFLP扩增片段的遗传相似率为0.7539;(2)两种石斑鱼存在杂交现象,RAPD、AFLP的扩增谱图中均获得亲本与子代的特异性条带,父本对杂交子代的遗传影响略大于母本;(3)AFLP标记在点带和斜带石斑鱼及其杂交子代中的遗传符合孟德尔遗传规律,可用于构建两种石斑鱼的遗传连锁图谱.研究结果将对两种石斑鱼种质资源的保护及人工繁育的可续性提供重要参考.  相似文献   

青岛和烟台滨海海、气温差的时间变化     

王少文  薛德强  赵绪孔 《海洋科学进展》1994,(2)

本文根据近３０ａ来青岛和烟台逐月气温及滨海水温资料，分析了青岛和烟台海、气温差的时间变化，发现秋、冬季节南岸青岛海、气温差大于北岸烟台；春、夏季则相反．通常当年平均或季平均气温为负距平时，年平均或冬季平均海、气温差为正距平，而夏季平均海、气温差为负距平，对于ＥｌＮｉｎｏ及反ＥｌＮｉｎｏ年结论与之相反．  相似文献   

Determination of snow water equivalent over the eastern part of Turkey using passive microwave data     

A. Unal Sorman  Ozgur Beser 《水文研究》2013,27(14):1945-1958

Information on regional snow water equivalent (SWE) is required for the management of water generated from snowmelt. Modeling of SWE in the mountainous regions of eastern Turkey, one of the major headwaters of Euphrates–Tigris basin, has significant importance in forecasting snowmelt discharge, especially for optimum water usage. An assimilation process to produce daily SWE maps is developed based on Helsinki University of Technology (HUT) model and AMSR‐E passive microwave data. The characteristics of the HUT emission model are analyzed in depth and discussed with respect to the extinction coefficient function. A new extinction coefficient function for the HUT model is proposed to suit models for snow over mountainous areas. Performance of the modified model is checked against the original, other modified cases and ground truth data covering the 2003–2007 winter periods. A new approach to calculate grain size and density is integrated inside the developed data assimilation process. An extensive validation was successfully performed by means of snow data measured at ground stations during the 2008–2010 winter periods. The root mean square error of the data set for snow depth and SWE between January and March of the 2008–2010 periods compared with the respective AMSR‐E footprints indicated that errors for estimated snow depth and predicted SWE values were 16.92 cm and 40.91 mm, respectively, for the 3‐year period. Validation results were less satisfactory for SWE less than 75.0 mm and greater than 150.0 mm. An underestimation for SWE greater than 150 mm could not be resolved owing to the microwave signal saturation that is observed for dense snowpack. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

A new approach of dynamic monitoring of 5‐day snow cover extent and snow depth based on MODIS and AMSR‐E data from Northern Xinjiang region     

Hui Yu  Xuetong Zhang  Tiangang Liang  Hongjie Xie  Xianwei Wang  Qisheng Feng  Quangong Chen 《水文研究》2012,26(20):3052-3061

Taking the Northern Xinjiang region as an example, we develop a snow depth model by using the Advanced Microwave Scanning Radiometer‐Earth Observing System (AMSR‐E) horizontal and vertical polarization brightness temperature difference data of 18 and 36 GHz bands and in situ snow depth measurements from 20 climatic stations during the snow seasons November–March) of 2002–2005. This article proposes a method to produce new 5‐day snow cover and snow depth images, using Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products and AMSR‐E snow water equivalent and daily brightness temperature products. The results indicate that (1) the brightness temperature difference (Tb_18h–Tb_36h) provides the most accurate and precise prediction of snow depth; (2) the snow, land and overall classification accuracies of the new images are separately 89.2%, 77.7% and 87.2% and are much better than those of AMSR‐E or MODIS products (in all weather conditions) alone; (3) the snow classification accuracy increases as snow depth increases; and (4) snow accuracies for different land cover types vary as 88%, 92.3%, 79.7% and 80.1% for cropland, grassland, shrub, and urban and built‐up, respectively. We conclude that the new 5‐day snow cover–snow depth images can provide both accurate cloud‐free snow cover extent and the snow depth dynamics, which would lay a scientific basis for water management and prevention of snow‐related disasters in this dry and cold pastoral area. After validations of the algorithms over other regions with different snow and climate conditions, this method would also be used for monitoring snow cover and snow depth elsewhere in the world. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Search for radio pulsations in four anomalous X-ray pulsars and discovery of two new pulsars     

Marta Burgay  Nanda Rea  GianLuca Israel  Andrea Possenti  Luciano Burderi  Tiziana Di Salvo  Nichi D’Amico  Luigi Stella  Elisa Nichelli 《Astrophysics and Space Science》2007,308(1-4):531-534

We have performed deep searches for radio pulsations from four southern anomalous X-ray pulsars (AXPs) to investigate their physical nature in comparison with the rotation powered pulsars. The data were acquired using the Parkes radio telescope with the 1.4 GHz multibeam receiver. No pulsed emission with periodicity matching the X-ray ephemeris have been found in the observed targets down to a limit of ∼0.1 mJy. A blind search has also been performed on all the 13 beams of the multibeam receiver (the central beam being pointed on the target AXP), leading to the serendipitous discovery of two new radio pulsars and to the further detection of 18 pulsars. Also a search for single dispersed pulses has been performed in the aim to detect signals similar to those of the recently discovered rotating radio transients.   相似文献