Dynamics and Variability of Terra Nova Bay Polynya   总被引：1，自引：0，他引：1  

Giannetta Fusco  Daniela Flocco  Giorgio Budillon  Giancarlo Spezie  Enrico Zambianchi 《Marine Ecology》2002,23(S1):201-209

Abstract. We present a process study on the dynamics and variability of the Terra Nova Bay polynya in the western sector of the Ross Sea. The air-sea heat exchange is known to be particularly large in polynya during the winter, when differences between air and sea temperatures are large. We apply a 1-D model (Pease, 1987; Van Woert, 1999a, 1999b), which is modified in the latent heat parameterisation in order to account for time-dependent relative humidity and cloud coverage. Furthermore, the Ice Collection Depth is correlated linearly with a variable wind speed. The model is forced with two different meteorological data sets: the operational analysis of the European Center for Medium Range Weather Forecasts atmospheric data set and the meteorological parameters measured by an Automatic Weather Station located on the coast of Terra Nova Bay. The results are compared in terms of polynya extension, ice, and High Salinity Shelf Water production. According to the two different wind velocities, the results obtained from the different data sets clearly differ. Qualitatively, however, the results are in good agreement.  相似文献   

Jellyfish patch formation investigated by aerial photography and drifter experiment     

Shinya Magome  Tomohiro Yamashita  Takeshi Kohama  Atsushi Kaneda  Yuichi Hayami  Satoru Takahashi  Hidetaka Takeoka 《Journal of Oceanography》2007,63(5):761-773

Jellyfish patch formation is investigated by conducting a drifter experiment combined with aerial photography of a sustained patch of the moon jellyfish in Hokezu Bay, Japan. Jellyfish patches are aggregations of individuals that are caused by a combination of swimming (active influence) and advection by currents (passive influence). The drifter experiment involved the injection of 49 drifters around a distinct surface patch of jellyfish within an area of approximately 300 m × 300 m. The drifters’ motion, caused only by the passive influence, was recorded in a series of 38 aerial photographs taken over approximately 1 h. The ambient uniform current field larger than the patch scale was estimated from the movement of the centroid position of drifters, while the distribution of horizontal divergence and relative vorticity around the patch was estimated from the time-derivative in areas of triangles formed by the drifters. The centroid positions of both drifters and patches moved stably toward the bay head at different speeds. The difference vector between the patch and drifter centroids was directed to the sun, and was opposite to the ambient current. The distributions of vorticity and divergence around patches exhibited inhomogeneity within the patch scale, and the drifters in this nonuniform current field aggregated near the convergence area within 1 h. The results suggest that horizontal patch formation is predominantly influenced by passive factors at the surface of Hokezu Bay. Furthermore, the upward swimming against downwelling may make sustained patch in surface layer.  相似文献   

柴达木盆地新构造运动主要特征与成因机制   总被引：10，自引：0，他引：10  

杨明慧 《海洋地质与第四纪地质》1997,17(3):71-78

研究表明，在壳幔结构、地球物理背景、沉积物结构、多层关地幔和构造样式等方面，达木盆地与中国东部新生代裂谷类伸展盆地具有可比性，应该归属 展性盆 。盆地伸展和收缩作用相间进行，伸展起因于地幔底辟；而收缩受两人因素影响；（１）盆地伸展作用受相邻造山带反作用诱导的挤压应力；（２）板块碰撞传递的远程板内应力。在此基础邮新的构造期达木盆地演化的“双层模式”，即地幔上隆－地壳伸展；被动挤压＋板内应力－地壳收缩  相似文献   

Water mass formation variability in the intermediate layer of the east sea     

Hong Sik Min  Cheol -Ho Kim 《Ocean Science Journal》2006,41(4):255-260

Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing at deeper depths in the intermediate layer took place in the late 1960’s and the mid-1980’s. Records of winter sea surface temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods. Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960’s and the Central Water in the mid-1980’s.  相似文献   

WATER MASS FORMATION IN THE SOUTH INDIAN OCEAN BY AIR-SEA FLUXES     

Ming Feng 《热带海洋学报》2004,23(6):16-21

1Introduction　TheIndianCentralWater (ICW) ,formedandsubductedintheSubtropicalConvergenceintheSouthIndianOcean ,occupiesasignificantportionofthethermoclineintheIndianOcean[1,2 ]　 (Fig .1 ) .TheSubantarcticModeWater(SAMW)isformedinthe 2 6.5-2 7.1σθrangenorthoftheSub antarcticFront—thesouthernboundaryofthesubtropicalgyres[3]　 .InthesoutheastIndianO cean ,theSAMWisthethickest,ventilatedasathicklayerofhighoxygenextendingtothetropicalIndianOcean[4 ,5 ]　 .　Watermasstransformation…  相似文献   

天然气水合物的形成与识别   总被引：3，自引：0，他引：3  

师生宝 《海洋地质前沿》2006,22(10):14-19

探讨了天然气水合物矿藏的形成条件和机理、水合物矿藏的聚集方式。天然气水合物的形成除了必要的气体和水,还需要一定的温压和地质条件;其形成机理可用高渗漏系统和弱渗漏系统来解释;天然气水合物在沉积物中主要以构造聚集和地层聚集的方式存在。综述了天然气水合物矿藏的识别方法。  相似文献   

褐藻酸降解菌的产酶条件研究   总被引：1，自引：0，他引：1       下载免费PDF全文

王艳玲  唐学玺  杨震 《海洋科学》2003,27(2):52-55

以海带病烂处分离到的别单胞菌属（Alkteromonas)的褐藻酸降解菌菌株A1为研究对象，在该菌的产酶条件进行了研究。结果表明，产酶的最适温度20℃，褐藻酸钠浓度（质量分数）0．5％－0．6％，pH7.5，盐度15，氮源为（NH4)2SO4，培养时间72h。  相似文献   

喀什凹陷中生代以来的构造事件对中-下侏罗统铀矿化的影响   总被引：2，自引：0，他引：2  

李盛富  王果 《国外铀金地质》2008,(1):7-12

喀什凹陷是我国西部重要的含铀区,自中生代以来主要发生过5次重大构造事件,对该地区中-下侏罗统铀矿成矿及保矿具有重要意义,即晚三叠世有利的构造背景,早-中侏罗世有利的构造-沉积环境形成的有利岩性-岩相建造,晚侏罗世构造掀斜与古层间氧化带及铀矿化的形成,白垩纪-古近纪的保矿作用及新近纪以来的构造破坏与局部层间氧化带的形成与叠加,从而很可能在中-下侏罗统中形成一定规模受层间氧化带控制的砂岩型铀矿床。指出主要找矿靶区为库孜贡苏断陷以西的南天山山前,同时还有托云盆地。  相似文献   

Bottom Simulating Reflector and Gas Seepage in Okinawa Trough： Evidence of Gas Hydrate in an Active Back-Arc Basin     

栾锡武  Kelin  Wang  Roy  Hyndman  Eleanor  Willoughby 《中国地质大学学报(英文版)》2008,19(2):152-161

To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation:to help gather enough methane into a small area and to modulate the thermal regime.  相似文献   

Formation Models and Distribution of Oil and Gas Pools in Tarim Basin,China     

龙胜祥 《中国地质大学学报(英文版)》2008,19(6):665-674

This article reports the main formation models and distribution of the oil and gas pools in Tarim basin,China,including (I) occurrence of the found oil and gas pools,(2) main formation models of oil and gas pools,and (3) distribution law of oil/gas pools.Petroleum is distributed widely in the strata of Tarim basin from the Sinian at the bottom to the Neogene at the top.However,the found oil and gas fields are mainly distributed in Shaya (沙雅) uplift,Tazhong (塔中) uplift,and Kuche (库车)depression.This article presents 4 main formation models,namely,early formation and long-term preservation,early formation and late reformation,middle-late multiphase-multisource formation,late single-stage formation.Tarim basin is very rich in petroleum resources.Long-term inherited intrabasinal paleohighs and slope zones are the most favorable areas for accumulation of hydrocarbons,but the types of oil and gas pools are different from area to area.The control of unconformities and faults on hydrocarbon accumulating is prominent in Tarim basin.Preservation conditions are of utmost importance.Formation of some oil and gas pools is the result of reforming and re-accumulating of early accumulated hydrocarbons.  相似文献