浙江沿海大雾的时空分布特征及影响因子分析     

俞燎霓  胡波  黄新晴  黄娟 《气象科技》2017,45(2):324-330

利用1958—2012年33个浙江沿海气象站资料,统计分析浙江沿海大雾时空分布特征和生、消特点,以及沿海大雾与地面风向风力的关系。得出以下结论:年均出现大雾10天以上的有28个站,整个沿海地区分布比较均匀;1971—2012年浙江沿海年平均有51.7天6个以上的基准站出现大雾,且有较明显的年际特征;沿海大雾有明显的季节性和月际变化,以春季和初夏出现次数最多;沿海大雾有明显的日变化特征,23:00至次日06:00是大雾生成的主要时段,而大雾消散时间主要集中在06:00—10:00。沿海大雾大部分在南风条件下发生,一般风力小于12m/s。文中还分析了2005—2011年出现沿海大雾时的天气形势,发现浙江处在入海变性冷高压西部、地面低压倒槽东部、静止锋或冷锋前部、弱高压底部、鞍形场,日本海高压西南部等6种天气形势下容易出现沿海大雾。  相似文献   

抓住奥运机遇,加快青岛海洋旅游开发研究   总被引：4，自引：0，他引：4  

董玉明  盛红  陈娟 《海岸工程》2003,22(1):91-94

青岛市作为2008年北京奥运会唯一的伙伴城市，将给青岛海洋旅游开发提供难得的机遇，产生重大而积极的影响。为了加快青岛海洋旅游开发的进程，尽快与国际海洋旅游接轨，必须抓住这一机遇，采取应对措施。  相似文献   

Possible diapirs in the gulf of Elat,Southern Dead Sea rift     

Yossi Mart  Philip D. Rabinowitz 《Geo-Marine Letters》1984,4(2):63-67

Elongate trending diapiric structures occur along faulted rifts in the Gulf of Elat. Those diapirs in the southern part of the Gulf, believed to be of salt origin were formed in the embryonic continental margin during the separation of the Nubian and Arabian plates. The diapirs farther to the north are believed to be of shale origin. These findings support other recent geological evidence suggesting that the tectonic regime in the region is obliquely extensional. Comparison with the structure of the Suez Rift indicates a jump of the northern extension of the Red Sea spreading center during the early Pliocene period.  相似文献   

High-resolution seismic imaging of gas accumulations and seepage in the sediments of the Ria de Aveiro barrier lagoon (Portugal)     

Henrique Duarte  Luis Menezes Pinheiro  Francisco Curado Teixeira  José Hipólito Monteiro 《Geo-Marine Letters》2007,27(2-4):115-126

Methane is a powerful greenhouse gas and an important energy source. The global significance and impact in coastal zones of methane gas accumulation and seepage in sediments from coastal lagoon environments are still largely unknown. This paper presents results from four high-resolution seismic surveys carried out in the Ria de Aveiro barrier lagoon (Portugal) in 1999, 2002 and 2003. These comprise three chirp surveys (RIAV99, RIAV02, RIAV02A) and one boomer survey (RIAV03). Evidence of extensive gas accumulation and seepage in tidal channel sediments from the Ria de Aveiro barrier lagoon is presented here for the first time. This evidence includes: acoustic turbidity, enhanced reflections, acoustic blanking, domes, and acoustic plumes in the water column (flares). The stratigraphy and structural framework control the distribution and extent of gas accumulations and seepage in the study area. In these shallow systems, however, tidal altitude variations have a significant impact on gas detection using acoustic methods, by changing the raw amplitude of the enhanced seismic reflections, acoustic turbidity, and acoustic blanking in gas-prone areas. Direct evidence of gas escape from drill holes in the surrounding area has shown that the gas present in the Ria de Aveiro consists of biogenic methane. Most of the gas in the study area was probably generated mainly in Holocene lagoon sediments. Evidence of faults affecting the Mesozoic limestones and clays underlying some of the shallow gas occurrences, and the presence of high-amplitude reflections in these deeper units raise the possibility that some of this gas could have been generated in deeper sedimentary layers, and then migrated upward through the fractured Mesozoic strata.  相似文献   

Underwater Acoustic Communication Based on Pattern Time Delay Shift Coding Scheme   总被引：1，自引：0，他引：1  

殷敬伟  惠俊英惠娟姚直象  王逸林 《中国海洋工程》2006,20(3):499-508

1 .Introduction Underwater acoustic (UWA) communicationis a fast developingfield,and its applicationis notlimitedto military affairs ,but is also extendinginto commercial fields .Catipovic (1990) ,Stojanovic(1996) and Kilfoyle and Baggeroer (2000) pointed…  相似文献   

Use of a tropical bay in southeastern Brazil by juvenile and subadult Micropogonias furnieri (Perciformes, Sciaenidae)     

da Costa  Marcus R; Araujo  Francisco G 《ICES Journal of Marine Science》2003,60(2):268-277

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Effects of mining wastes on a seagrass ecosystem: metal accumulation and bioavailability, seagrass dynamics and associated community structure   总被引：1，自引：0，他引：1  

Marín-Guirao L  Atucha AM  Barba JL  López EM  Fernández AJ 《Marine environmental research》2005,60(3):317-337

Two different Cymodocea nodosa (Ucria) Ascherson beds growing in mining-contaminated sediments were compared with two reference beds in the Mar Menor coastal lagoon. The accumulation of Zn, Pb and Cd in different fractions of the plant, the sediment parameters that regulate the availability of metals, the seabed structure and dynamics of each seagrass bed and its associated macroinvertebrate community were studied. C. nodosa accumulates metals from the sediments and reflects their bioavailability for this seagrass. At each station, the metal content of the rhizomes was lower than that of leaves and roots. The concentration of acid-volatile sulfides does not seem to influence the availability of metals to the seagrass, possibly due to oxygen transport to underground tissues. The highest metal concentration in all the contaminated stations was found in the leaf-biofilm, due to the formation of complexes between metals and the extracellular polymeric substances that form the biofilm. All the seagrass beds were seen to be undergoing expansion, those growing in contaminated sediments accumulating great quantities of metals and showing highest photosynthetic leaf surface area and highest leaf biomass. However, these structural parameters were not seen to be responsible for the differences in the faunal composition observed between contaminated and reference beds. Moreover, the multivariate analysis identified the metal content of leaves, biofilm and sediments as important variables that may be responsible for these differences in faunal composition. In this study we have demonstrated that both the seagrass C. nodosa and the biofilm on the plant leaves may be used as environmental tools in the Mar Menor lagoon. The former is an useful indicator of sediment contamination, whereas the latter seems to be a good sentinel of water quality.  相似文献   

潮坪层序的粒度特征与沉积相划分--以杭州湾庵东浅滩为例   总被引：1，自引：0，他引：1  

郭艳霞  范代读  赵娟 《海洋地质前沿》2004,20(5):9-14

现代潮滩依据多年平均潮位线划分高、中、低潮滩，这对于古代潮坪沉积相研究无实际意义。本文尝试用潮坪层序粒度参数剖面来划分沉积相。潮坪沉积物以粉砂为主，但敏感地反映沉积动力变化的却是粗、细尾部分。因此，在沉积相划分时主要依据粘土、砂含量及平均粒径的变化特征。分选系数是一重要依据，但要考虑絮凝沉积的影响。偏态和峰态变幅小、较复杂，在相划分中只具参考价值。利用粒度参数剖面进行潮坪沉积相划分可广泛应用于古代潮坪层序研究，而且根据中潮坪沉积厚度(x)与平均潮差(y)存在的显著性相关关系：y=1．8314x 157．31(单位cm)，推算古潮差。  相似文献   

Effectiveness of the structural fisheries policy in the European Union     

Juan C. Surís-Regueiro  Manuel M. Varela-Lafuente  Carlos Iglesias-Malvido 《Marine Policy》2003,27(6):535-544

This paper presents an analysis of the effectiveness of the community structural policy in the fisheries sector by comparing the relative level of compliance with objectives (reduction of fleets and economic viability) with the mechanisms that have been implemented (structural funds and allocation of quotas). On the one hand, this analysis shows that there is a positive correlation between the level of structural funds and the attainment of goals. On the other hand, it was found that the greater the relative availability of quotas, the poorer the countries performed in complying with the objective of reducing the fishing capacity, and the higher the expectations of achieving acceptable yields. These correlations, however, were not very strong.  相似文献   

Diel variation in the vertical distribution and schooling behaviour of sardine (Sardina pilchardus) off Portugal     

Zwolinski  Juan; Morais  Alexandre; Marques  Vitor; Stratoudakis  Yorgos; Fernandes  Paul G. 《ICES Journal of Marine Science》2007,64(5):963-972

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