Experimental investigation on a two-part underwater towed system

An experimental set-up is developed and proved to be effective for laboratory study of an underwater towed system. The experimental technique gives a practical method for monitoring the kinematic and dynamic performance of an underwater towed system in a ship towing tank. Both the theoretical and experimental results in the investigation indicate that the hydrodynamic response of a towed vehicle to the wave induced motion of a towing ship can be significantly reduced by applying a two-part tow method. A comparison of the numerical and experimental results in the investigation demonstrates that the numerical simulation results are close to the experimental data, overall agreement between experimental and theoretical results is satisfactory. The results qualitatively verify the mathematical model of a two-part underwater towed system proposed by Wu and Chwang [Wu, J., Chwang, A.T., 2000. A hydrodynamic model of a two-part underwater towed system. Ocean Engineering 27 (5), 455–472].     

千里岩的气温变化特征及其与西北太平洋副热带高压的关系

本文根据１９６０～１９９４年千里岩和青岛月平均气温资料，分析了千里岩与青岛３５年来气温的年、季变化特征及差别，发现３５年来，千里岩和青岛的年、季平均气温均呈变暖趋势，但千里岩增温幅度较青岛小。从分析中发现，与气温变暖趋势相对应，西北太平洋副热带高压（以下简称副高）面积、强度指数的年、季变化也呈明显的增强、增大趋势。且年平均气温与冬季副高面积指数相关最显著。最后依此关系建立回归方程，并预测了１９９６年千里岩年平均气温的变化趋势。     

苏北盐城凹陷复合含油气系统

苏北盐城凹陷含油气系统可划分为上、下2个复合含油气系统。上复合含油气系统，即Pz、K2p、K2t(生)-K2t、E1f1(储)一E1f1 E1f2(盖)，古生界、中生界浦口组和泰州组为烃源岩层，泰州组和阜宁组一段为储集层，阜宁组一段顶部至二段暗色泥岩为区域盖层，油气沿深大断裂运移，油气成藏关键时刻在古近纪晚期至新近纪早期，有利勘探区在深大断裂附近的中、新生界发育地区；下复合含油气系统，即Pz、K2p(生)-Pz、K2p(储)-K2p3 K2p4(盖)，油气通过断层或不整合运移，油气大量生成的关键时刻为古近纪早期，该系统中气藏分布在古生界被中生界覆盖地区。     

数字地球与海洋科学的发展

本文从数字地球的概念出发，根据海洋科学的发展要求，详细论述了数字地球与海洋科学的发展关键。并提出了海洋科学的新的发展战略和配套技术的开发研究理论，从而为我国海洋事业的发展和数字地球的建立有一个协调和统一的认识观点。     

A novel time-series station in the Wadden Sea (NW Germany): First results on continuous nutrient and methane measurements

In autumn 2002 a time-series station was installed in the tidal inlet between the Islands of Langeoog and Spiekeroog (Southern North Sea, NW Germany) to continuously measure physical, chemical, and meteorological parameters, even during extreme weather conditions (gale-force storms, drifting ice). Inside the pole of the station sensor tubes are installed in direction of the prevailing tidal currents. The tubes are equipped with hydrographic sensors (pressure, temperature, conductivity) and allow retrieval of water for nutrient analysis by automated instruments located inside the pole. Dissolved methane and the nutrients ammonia, nitrite, nitrate, phosphate, and silicate are measured at the station.     

Response-based method for determining the extreme behaviour of floating offshore platforms

The accurate prediction of extreme excursion and mooring force of floating offshore structures due to multi-variete environmental conditions which requires the joint probability analysis of environmental conditions for the worst case situation is still impractical as the processing of large amount of met-ocean data is required. On the other hand, the simplified multiple design criteria (e.g. the N-year wave with associated winds and currents) recommended by API known as traditional method does lead neither to the N-year platform response nor to the N-year mooring force. Therefore, in order to reduce the level of conservatism as well as uncertainties involved in the traditional method the response-based method can be used as a reliable alternative approach. In this paper this method is described. In order to perform the calculations faster using large databases of sea states, Artificial Neural Networks (ANN) is designed and employed. In the paper the response-based method is applied to a 200,000 tdw FPSO and the results are discussed.