Calibration of JASON-1 Altimeter over Lake Erie     

C. Shum  Y. Yi  K. Cheng  C. Kuo  A. Braun  S. Calmant  D. Chambers 《Marine Geodesy》2003,26(3):335-354

This article describes absolute calibration results for both JASON-1 and TOPEX Side B (TSB) altimeters obtained at the Lake Erie calibration site, Marblehead, Ohio, USA. Using 15 overflights, the estimated JASON altimeter bias at Marblehead is 58 ± 38 mm, with an uncertainty of 19 mm based on detailed error analysis. Assuming that the TSB bias is negligible, relative bias estimates using both data from the TSB-JASON formation flight period and data from 48 water level gauges around the entire Great Lakes confirmed the Marblehead results. Global analyses using both the formation flight data and dual-satellite (TSB and JASON) crossovers yield a similar relative bias estimate of 146 ± 59 mm, which agrees well with open ocean absolute calibration results obtained at Harvest, Corsica, and Bass Strait (e.g., Watson et al. 2003). We find that there is a strong dependence of bias estimates on the choice of sea state bias (SSB) models. Results indicate that the invariant JASON instrument bias estimated oceanwide is 71 mm, with additional biases of 76 mm or 28 mm contributed by the choice of Collecte Localisation Satellites (CLS) SSB or Center for Space Research (CSR) SSB model, respectively. Similar analysis in the Great Lakes yields the invariant JASON instrument bias at 19 mm, with the SSB contributed biases at 58 mm or 13 mm, respectively. The reason for the discrepancy is currently unknown and warrants further investigation. Finally, comparison of the TOPEX/POSEIDON mission (1992-2002) data with the Great Lakes water level gauge measurements yields a negligible TOPEX altimeter drift of 0.1 mm/yr.  相似文献   

大黄鱼倍性检测研究     

刘伟斌  谢湘筠  林向阳  曾志南  宋希坤 《台湾海峡》2006,25(1):48-53

于2001—2004年对人工诱导大黄鱼的不同发育阶段和不同组织进行倍性检测，胚胎眼泡期采用染色体计数法测定，鱼苗和成鱼阶段用流式细胞法，结果表明，胚胎染色体数目2n=48条为二倍体，3n=72条为三倍体．采用流式细胞法测定鱼苗和成鱼个体时，若受测样品的DNA相对含量值与已知对照组二倍体的比值约为1．5：1，其个体为三倍体；比值约为1：1，则为二倍体，无论用肌肉或尾鳍组织，皆可检测出其个体的倍性。  相似文献   

太平洋海域海平面变化的灰色系统分析   总被引：3，自引：1，他引：3  

左军成  陈宗镛  戚建华 《中国海洋大学学报(自然科学版)》1997,(2)

应用灰色系统理论，对太平洋海域４８个长期验潮站的月均海平面分别建立了ＧＭ（１，１）模型。ＧＭ（１，１）模型能较好地反映太平洋海域的海平面变化的趋势，它除了能给出连续的海平面变化速率外，同时能方便地给出海平面变化的加速率。模拟结果表明，在太平洋地壳均衡假设下，太平洋海域的月均海平面以平均速率０．１７ｃｍ／ａ上升。在太平洋海域所取的４８个长期验潮站中，有４０个站在加速上升，全部站的平均加速度为０．０００２９ｃｍ／ａ２。且加速率逐渐增大。当然这些加速率都很小，但作为一种普遍性的趋势，这已足以说明：太平洋海域的海平面在加速上升  相似文献   

海洋环流模式中不同近似假设下的海表高度   总被引：1，自引：1，他引：1  

李薇  张学洪  金向泽 《海洋科学进展》2003,21(2):132-141

Boussinesq近似是现代海洋环流模式中经常采用的假设，但随着海洋模式的不断发展完善以及气候研究应用的需要，有必要估算Boussinesq近似造成的模式误差。分别利用一个非Boussinesq近似的海洋模式与另一个结构相同且采用Boussinesq近似的模式计算海表高度，并同时利用模式预报的温度、盐度资料计算了比容异常高度。分析结果显示，这3种不同定义的海表高度无论空间结构，还是时间演变，都基本类似，尤其在热带海区最接近，差值≤1cm。Boussinesq近似意味着在模式中以体积守恒代替质量守恒，通常的做法是对其进行简单的质量补偿来保持质量守恒。比较说明，以质量补偿方法进行的高度订正对减小Boussinesq近似带来的误差没有本质的意义。  相似文献   

摄食水平和性别对稀有鮈鲫生长和能量收支的影响   总被引：7，自引：0，他引：7  

朱晓鸣  解绶启  崔奕波  杨云霞  光寿红 《海洋与湖沼》2001,32(3):240-247

于1995年10月采集本所自繁有ju鲫（约1.03g/ind)，在30℃水温下进行摄食－生长实验，研究了从饥饿到饱食5个摄食水平对不同性别稀有ju鲫的生长和能量收支的影响，结果表明，鱼体干物和能量含量不受摄食率和性别的影响，随着摄食率的增加，雌鱼的湿重，干重和能量特定生长率均呈双对数增加，雄鱼湿重特定生长率呈双对数增加，而干物质和能量特定生长率呈指增加，雄鱼生长速度及摄食率低于雌鱼，随着摄食率的增加，食物能损失于粪便中的比例均呈上升趋势，损失于排泄物中的比例变化不大，呈下降趋势，用于代谢的比例呈下降趋势，用于生长的比例呈上升趋势，除饥饿组外，在各个摄食水平，雌鱼食物能用于代谢的比例较雄鱼低，而用于生长的比例较雄鱼高。  相似文献   

沃克环流上升区赤道低空强西风带的分析     

李若钝  于惠苓  刘丽惠  孙瑞本  井传才  苏新锁 《热带海洋学报》1995,(1)

采用ＴＯＧＡ／ＣＯＡＲＥ国际合作考察期间（１９９２年１０月─１９９３年２月）获得的２６７次定点（２°Ｓ，１５５°Ｅ）定时高空大气探测资料，进行计算分析，发现１９９２年１２月─１９９３年２月低空存在一支西风急流，有两次分别持续半月之久，而１９９２年１１月的两次赤道西风急流，因无赤道高空急流配合，仅持续２ｄ便消失。本文还指出：（１）赤道低空西风急流是各种海－气指数产生ＥＮＳＯ异常的重要信息；（２）赤道高空急流有滞后赤道低空急流２ｄ左右的响应关系；（３）赤道低空急流是纬向水汽输送的狭窄通道。  相似文献   

Research on the spectral analysis and test method of period signals in monthly mean sea level     

Ma Jirui  Tian Suzhen  Zheng Wenzhen  Chai Xinmin 《海洋学报(英文版)》1995,14(2):181-190

Ｒｅｓｅａｒｃｈｏｎｔｈｅｓｐｅｃｔｒａｌａｎａｌｙｓｉｓａｎｄｔｅｓｔｍｅｔｈｏｄｏｆｐｅｒｉｏｄｓｉｇｎａｌｓｉｎｍｏｎｔｈｌｙｍｅａｎｓｅａｌｅｖｅｌ￥ＭａＪｉｒｕｉ；ＴｉａｎＳｕｚｈｅｎ；ＺｈｅｎｇＷｅｎｚｈｅｎａｎｄＣｈａｉＸｉｎｍｉｎ（Ｒ...  相似文献   

南海輓近海平面变化与构造升降初步研究     

刘以宣  詹文欢  陈欣树  陈俊仁  陈特固  许时耕 《热带海洋学报》1993,(3)

揭示南海輓近海平面变动和古岸线诸多遗迹,探讨晚更新世以来海平面变化一般规律,初步分析南海周缘中全新世和现代地壳构造升降速率,得出本区海平面上升率适中参考值为0.10—2.0mm/a,初步估算未来50年内海平面变化趋势在1.26—4.0mm/a之间;而构造升降受块断差异运动控制,一般规律是南海北部沿岸自东向西递减,由福建南部1.15mm/a至海南岛南部0.54mm/a。近代地壳形变资料亦证实这种变化规律。  相似文献   

Factors involved in growth plasticity of cockles Cerastoderma edule (L.), identified by field survey and transplant experiments     

Xavier De Montaudouin 《Journal of Sea Research》1996,36(3-4)

In Arcachon Bay, a macrotidal coastal lagoon in southwest France, growth rates of cockles Cerastoderma edule (L.) differ greatly between locations. Sampling of populations at different tidal levels showed that the mean shell length was significantly and positively correlated with immersion time, whereas no correlation was found with population density and microphytobenthos biomass. Transplants of cockles between two intertidal sites were used to examine the relative importance of habitat and site of origin for growth rate and condition index. Artifacts due to manipulation were assessed, i.e. the impact of enclosures on growth, conditon index and mortality. During a 5-mo reciprocal transplant experiment, growth rates of the transplanted cockles and the cockles already present were similar, whereas the sites of origin did not affect growth rate. Condition index, however, displayed significant differences in relation to both transplant and origin sites. During a further 6-mo experiment in which cockles were transplanted from one site to four new sites, growth was mainly influenced by tidal level. These results indicate that net growth started when cockles were immersed 30% of the time. It is concluded that, on the scale of Arcachon Bay (156 km²), differences in growth and condition between cockle populations are largely phenotypic. Tidal level (i.e. food supply and emersion stress) accounts for most of these differences, but the existence of genetically or physiologically different populations cannot be excluded.  相似文献   

Seasonal and Spatial Variations of Iceberg Drift off Dronning Maud Land, Antarctica, Detected by Satellite Scatterometers   总被引：1，自引：0，他引：1  

Shigeru Aoki 《Journal of Oceanography》2003,59(5):629-635

Seasonal and spatial variations of iceberg drift were studied using continuous satellite scatterometer images off Dronning Maud Land, East Antarctica. Generally, iceberg drift speed showed a westward increase to the Greenwich Meridian. Seasonal variations of the drift speed were high in autumn—early winter and low in spring, and their magnitudes also increased westward. Seasonal variations of the drift speed were significantly correlated with variations of sea levels at Syowa and Mawson Stations, and hence qualitatively consistent with geostrophic current variations. Thus, the scatterometer data are demonstrated to be useful in monitoring iceberg trajectory and oceanic current variations. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献