台湾岛周边海域近16a来海平面变化研究     

阮海林  杨燕明  李燕初  陈海颖 《台湾海峡》2010,29(3):394-401

利用1992年10月至2008年6月的卫星高度计融合资料对台湾岛周边海域（20°～28°N,117°～124°E）多年海平面变化进行分析.研究结果表明：（1）采用改进的月平均水位周期信号的谱分析方法计算多年来台湾岛周边海域海平面年均上升速率为0.34±0.02 cm/a,与该海域内的潮位站结果较为一致.（2）台湾岛周边海域海平面高度变化以1 a周期变化为主,其次为0.5 a、准2 a周期变化.（3）通过计算海平面异常的标准差得出多年来台湾海峡西南部海域海平面波动最为激烈.（4）分析了台湾岛周边海域海平面4个季节的变化情况,指出台湾岛周边海域海平面季节变化的主要驱动力是风场.  相似文献   

三沙市海域海平面变化   总被引：2，自引：3，他引：2  

王慧  刘克修  张建立  范文静 《海洋学报》2013,35(3):11-17

使用1993-2011年的台站和卫星高度计资料详细分析了三沙市海域近19 a的海平面变化特征及规律。结果表明:三沙市周边海域海平面存在明显的季节变化,且区域特征明显。海平面变化除了明显的年和半年周期,2~3 a、4~7 a和准9 a的周期也较显著。海平面长期变化呈现明显的波动上升趋势,且空间分布上区域特征显著,西沙群岛南部海域海平面上升趋势最强,西沙群岛北部与中沙群岛西部次之,南沙群岛东部海平面上升速率较快,南沙群岛西部上升趋势最弱。受大气环流等异常气候事件的影响,1998年和2010年海平面的年际变化波动较大,年变化振幅显著偏高。未来三沙市海平面将继续上升,预计2030年、2050年、2070年和2100年海平面将比常年分别升高约11 cm、20 cm、30 cm和45 cm。  相似文献   

热带大西洋公海金枪鱼延绳钓海龟兼捕的初步研究   总被引：2，自引：0，他引：2  

庄之栋  戴小杰  许柳雄 《海洋湖沼通报》2011,(2)

根据2007-2010年间2次科学观察员对热带大西洋公海海域(05°37′N～14°59′N,29°00′W～40°54′W)金枪鱼延绳钓渔业的调查,共投钩236次(d),兼捕到棱皮龟和太平洋丽龟2种共23尾,其中死亡8尾,兼捕率为0.03461尾/千钩(0.09746尾/次),上钩后死亡率为34.8%.兼捕海龟的位置范围为06°N～12°N,29°W～38°W.从海龟的钓获部位看,喙部占43.5%;前肢占26.1%;躯干占8.7%;喉部占8.7%;被主绳缠绕占13.0%.此外分析了不同钩深与兼捕海龟数量之间的关系,探讨了影响兼捕率和上钩后死亡率的因素,提出相关保护对策.  相似文献   

浙江近海潮流和余流的特征   总被引：5，自引：0，他引：5  

陈倩  黄大吉  章本照  王敏芳 《海洋学研究》2003,21(4):1-14

依据近年来浙江海岸带和海岛调查的实测海流数据,研究了浙江近海的潮流、余流特征和分布规律。由实测数据得到调和分析的一些参数,并根据这些参数分析了浙江近海的潮流性质、潮流运动形式、最大可能流速、M2分潮潮流椭圆、潮流的垂直分布及冬、夏季的余流分布,从而对浙江近海整个区域的潮流、余流特性有了一个较为全面的认识。  相似文献   

值得重视的海域海相油气勘探   总被引：1，自引：0，他引：1  

温珍河  刘守全  陈建文  龚建明  肖国林  蔡峰  许红 《海相油气地质》2007,12(3):5-9

当前我国海域油气的勘探领域和勘探层位大部分局限于新生界,而对古生代海相地台沉积、特提斯海相沉积、南海生物礁、南海和冲绳等深水盆地领域的勘探涉足不深。通过海域海相油气的地质调查与研究以及新区评价,认为在我国海域拓宽找油的战略选区,力争海域海相油气勘探获得突破、发现储量规模大的整装油田是有可能的。  相似文献   

The grain-size characterisation of coastal sand from the Somme estuary to Belgium: Sediment sorting processes and mixing in a tide- and storm-dominated setting     

Edward J. Anthony  Arnaud Héquette 《Sedimentary Geology》2007,202(3):369-382

Sand-rich Holocene to modern clastic deposits in the eastern English Channel and the southern North Sea coasts of France and Belgium occur extensively as nearshore-sand bank, estuarine-tidal flat, aeolian dune and beach sub-environments. Sand samples (n = 665) collected from these deposits suggest the presence of three different populations: a largely dominant (83%) medium to fine quartz sand population (“b”), and finer- (14%) and coarser-grained (4%) populations (respectively “c” and “a”). The distribution of these populations among the four sub-environments reflects tide- and storm-dominated sorting and transport processes and a variable degree of mixing. These populations are derived from a mixture of very fine- to very coarse-grained fluvial, outwash and paraglacial sediments deposited on the beds of the eastern English Channel and southern North Sea during the late Pleistocene lowstand. The nearshore-sand bank environment, which also corresponds to the main offshore source area of the coastal deposits, exhibits population heterogeneity reflecting the variability of hydrodynamic conditions and sediment sorting in this zone. The nearshore topography of tidal ridges, banks and troughs in these tidal seas leads to variable bed and tide- and storm-induced shear stress conditions. These conditions only allow for the mobilisation and onshore transport of some of the finer fractions (populations “b” and “c”), leaving an offshore mixture of these finer populations with coarser, less mobilisable sediments (population “a”). Once in the coastal zone, these two finer populations undergo further hydrodynamic sorting and segregation. Variably sorted very fine sands to silts (population “c”) are trapped in the low-energy estuarine-tidal flat sub-environment, while the highly homogeneous population “b” is further sorted in aeolian dune and beach sub-environments. This sorting occurs via a coastal sand transport pathway linking the Somme estuary mouth to the southern North Sea bight where tidal range and wave energy decrease relative to the English Channel. Since this sand transport pathway enables longshore transport of hydrodynamically sorted medium to fine sand derived directly from the immediate nearshore zone, it has further contributed to a net flux of this sand population from the eastern English Channel sea bed to the southern North Sea.  相似文献   

Seasonal variations in pCO₂ and its controlling factors in surface seawater of the northern East China Sea   总被引：2，自引：0，他引：2  

JeongHee Shim  Dongseon Kim  Young Chul Kang  Jae Hak Lee  Sung-Tae Jang  Cheol-Ho Kim 《Continental Shelf Research》2007,27(20):2623-2636

Surface partial pressure of CO₂ (pCO₂), temperature, salinity, nutrients, and chlorophyll a were measured in the East China Sea (ECS; 31°30′–34°00′N to 124°00′–127°30′E) in August 2003 (summer), May 2004 (spring), October 2004 (early fall), and November 2005 (fall). The warm and saline Tsushima Warm Current was observed in the eastern part of the survey area during four cruises, and relatively low salinity waters due to outflow from the Changjiang (Yangtze River) were observed over the western part of the survey area. Surface pCO₂ ranged from 236 to 445 μatm in spring and summer, and from 326 to 517 μatm in fall. Large pCO₂ (values >400 μatm) occurred in the western part of the study area in spring and fall, and in the eastern part in summer. A positive linear correlation existed between surface pCO₂ and temperature in the eastern part of the study area, where the Tsushima Warm Current dominates; this correlation suggests that temperature is the major factor controlling surface pCO₂ distribution in that area. In the western part of the study area, however, the main controlling factor is different and seasonally complex. There is large transport in this region of Changjiang Diluted Water in summer, causing low salinity and low pCO₂ values. The relationship between surface pCO₂ and water stability suggests that the amount of mixing and/or upwelling of CO₂-rich water might be the important process controlling surface pCO₂ levels during spring and fall in this shallow region. Sea–air CO₂ flux, based on the application of a Wanninkhof [1992. Relationship between wind speed and gas exchange over the ocean. Journal of Geophysical Research 97, 7373–7382] formula for gas transfer velocity and a set of monthly averaged satellite wind data, were −5.04±1.59, −2.52±1.81, 1.71±2.87, and 0.39±0.18 mmol m⁻² d⁻¹ in spring, summer, early fall, and fall, respectively, in the northern ECS. The ocean in this study area is therefore a carbon sink in spring and summer, but a weak source or in equilibrium with the atmosphere in fall. If the winter flux value is assumed to have been the mean of autumnal and vernal values, then the northern ECS absorbs about 0.013 Pg C annually. That result suggests that the northern ECS is a net sink for atmospheric CO₂, a result consistent with previous studies.  相似文献   

全球变化中的浅海沉积作用与物理环境演化——以渤、黄、东海区域为例   总被引：11，自引：0，他引：11  

高抒 《地学前缘》2002,9(2):329-335

以渤、黄、东海陆架区为例 ,综合评述入海沉积物通量、浅海沉积作用和人类活动影响下的物理环境变化。黄河、长江沉积物入海后主要堆积于河口附近 ,沉积速率为 10～ 10 0mm/a ,部分物质输运至陆架区 ,形成泥质沉积体 ,其沉积速率为 1mm/a量级。但目前河流入海沉积物通量呈减小趋势 ,今后河口附近的堆积将会减缓 ,并在总体上转化为侵蚀状态。在过去的 7ka里 ,来自黄河、长江等河流的沉积物形成了河口三角洲、滨海平原、潮流脊和潮汐汊道沉积体系 ,其演化方式是双重的 ,既有常态边界条件和外力作用下的演化 ,又有边界条件和外力作用发生变异时的演化。边界条件和外力作用变异的原因包括入海通量变化、全球气候变化、海面上升和人类活动等。建议从中国海岸带城市化发展的现状和需求出发 ,对此进行深入研究。  相似文献   

Climatic features of the Mediterranean Sea detected by the analysis of the longwave radiative bulk formulae     

M. E. Schiano  M. Borghini  S. Castellari  C. Luttazzi 《Annales Geophysicae》2000,18(11):1482-1487

Some important climatic features of the Mediterranean Sea stand out from an analysis of the systematic discrepancies between direct measurements of longwave radiation budget and predictions obtained by the most widely used bulk formulae. In particular, under clear-sky conditions the results show that the surface values of both air temperature and humidity over the Mediterranean Sea are larger than those expected over an open ocean with the same amount of net longwave radiation. Furthermore, the twofold climatic regime of the Mediterranean region strongly affects the downwelling clear-sky radiation. This study suggests that a single bulk formula with constant numerical coefficients is unable to reproduce the fluxes at the surface for all the seasons.  相似文献   

Is the pelagic-demersal ratio from fishery landings a useful proxy for nutrient availability? A preliminary data exploration for the semi-enclosed seas around Europe   总被引：5，自引：2，他引：3  

de Leiva Moreno  J. I.; Agostini  V. N.; Caddy  J. F.; Carocci  F. 《ICES Journal of Marine Science》2000,57(4):1091-1102

  相似文献