共查询到20条相似文献，搜索用时 15 毫秒
1.
《Marine Policy》2004,28(1):13-18
Naval strategy and operational focus are shifting toward regional and littoral warfare. The application to extended jurisdictional zones of rules formulated for 3 nm territorial seas is creating international tension as well as new roles for navies. But the argument that the Navy should control the EEZ has fundamental weaknesses. Tentative recommendations are given for reforming the rules of naval warfare in light of extended jurisdictional zones.The growing importance of Rules of Engagement (ROE) reflects a greater degree of control of the military by politicians. This and the spread of high tech weapons have made the operations of naval forces extremely complex. ROE are now being rewritten around three key elements—separation of prohibitions from permissions, determination of the political objective, and conformity between the rules and the force profile and objective. ROE must also be separated from rules of behavior, which are the province of the military. And multilateral naval operations in the same EEZ must have the same ROE. 相似文献
2.
Kaiji Jamaguchi 《Marine Policy》1982,6(2):151-154
These articles concern two countries with broadly similar diplomatic and military alignments but with defence policies which appear to be evolving in opposite directions. In the first article, Keith Speed MP, Parliamentary Under-secretary of State for the Royal Navy until May 1981, offers a critique of UK naval policy as outlined in the Defence White Paper of June 1981. In the second article, Kaiji Yamaguchi, a professor of international law and member of the Japanese Navy, analyses Japan's defence imperatives in the light of Soviet activity in North-east Asia and US pressure on the Japanese government to increase its defence budget. Both articles highlight the dilemma posed by Soviet expansionism requiring a positive response from the West and a world recession which demands reductions in public spending. 相似文献
3.
Keith Speed 《Marine Policy》1982,6(2):150-151
These articles concern two countries with broadly similar diplomatic and military alignments but with defence policies which appear to be evolving in opposite directions. In the first article, Keith Speed MP, Parliamentary Under-secretary of State for the Royal Navy until May 1981, offers a critique of UK naval policy as outlined in the Defence White Paper of June 1981. In the second article, Kaiji Yamaguchi, a professor of international law and member of the Japanese Navy, analyses Japan's defence imperatives in the light of Soviet activity in North-east Asia and US pressure on the Japanese government to increase its defence budget. Both articles highlight the dilemma posed by Soviet expansionism requiring a positive response from the West and a world recession which demands reductions in public spending. 相似文献
4.
Michael MccGwire 《Marine Policy》1980,4(4):317-322
The purpose of this article is to draw attention to a change in the trend of Soviet naval developments. This change stems from a combination of: (1) a sharp increase in the allocation of resources to naval shipbuilding; (2) a marked rise in the navy's political influence; and (3) a new approach to the role of seapower in Soviet policy. Professor MccGwire, Senior Fellow at the Brookings Institution, USA, believes that both the nature and the significance of the change are being obscured by the fact that for the past decade naval leaders in the West have been talking of ‘a Soviet naval build-up’, and continue to use the same language to describe the very different present situation. There is no general awareness, even within naval circles, that we are now facing a significant change in established trends. This article draws on a longer and more general article.1 相似文献
5.
Most international discussions on ballast water management onboard ships have been virtually on the prevention of the transport of biotic alien species. This study focuses on how to improve this limited knowledge regarding the transport of butyltin compounds via ballasting. Butyltin compounds in ballast water, extracted from three sea-going merchant ships with similar voyage routes and berth ports but with different ballasting practices, were determined. Only monobutyltin (8–57 ng l?1) and dibutyltin (10–32 ng l?1) onboard two general cargo ships were detected in the ballast water taken outside the ports. In contrast, significant tributyltin (23–93 ng l?1) was detected onboard the container ship in the ballast water pumped inside the loading/unloading ports. The comparison results from this study indicate that the risk of tributyltin transfer may be effectively prevented by ballasting outside the ports. 相似文献
6.
Seakeeping of two ships in close proximity 总被引：1，自引：0，他引：1
Underway replenishment is an essential component of long-term naval operations. During underway replenishment, two ships travel in close proximity at moderate forward speed. This paper examines the hydrodynamic interactions that can influence seakeeping during such operations. Presented numerical predictions include the influence of interaction effects on hydrodynamic forces for two ships in waves. A scarcity of validation material for numerical predictions prompted new towing tank experiments for two ships in waves. The experiments used semi-captive models, and the numerical code was modified to include restraining forces for specified modes. The numerical predictions and experiments show that the presence of a larger ship can significantly influence the motions of a smaller ship in close proximity. 相似文献
7.
《Ocean & Coastal Management》2006,49(9-10):779-788
Oil, chemicals and unexploded ordinances onboard sunken World War II (WWII) warships and merchant vessels pose a real and significant marine pollution risk to the nations of the Pacific and East Asia. A recent project of the South Pacific Regional Environment Program (SPREP), through its Pacific Ocean Pollution Prevention Program, has highlighted the extent of the risk posed by vessels lost in WWII to Member Governments. Some of these vessels have already begun to leak fuel oil and cargo into the fragile environment of the Pacific atolls. The oil spills from the oil tanker USS Mississinewa sunk in Ulithi Lagoon, Federated States of Micronesia, will be used as an example of the problems associated with WWII wrecks in the region.A Regional WWII Wreck Strategy was formulated and endorsed by the Members of SPREP, and a preliminary risk assessment of WWII shipwrecks was carried out by the program, as part of this exercise. This led to the development of a Geographic Information System (GIS) database, which details the types of ships, the tonnage and location of over 3800 vessels lost in the Pacific and East Asia. Although not complete, the Pacific WWII Shipwreck Database totals over 13 million tons of sunken vessels—ranging from aircraft carriers to battleships and including over 330 tankers and oilers.As a major proportion of vessels lost during WWII rest in the East Asian–Pacific sea area, close collaboration needs to be established between the regional environmental bodies and their affected Member Governments to address the scale of marine pollution risk. Complex maritime jurisdictional issues, along with overlapping claims on Economic Exclusion Zones and the interrelationships of the marine environments in the region, also underscore the need to address the issue on a multilateral basis.This paper aims to highlight the extent of the risks posed by sunken WWII vessels to fisheries, marine and coastal resources of the Pacific and East Asian regions, as well as the issues of ownership and responsibility for the WWII shipwrecks of the Pacific. 相似文献
8.
9.
During the 1982 invasion of southern Lebanon, the Israeli Air Force faced the problem of neutralizing the massive Syrian air defense network in the Bekka Valley as a step in gaining air control in the area. They accomplished this, in a matter of days, without the loss of a single aircraft, while inflicting a loss of over 80 aircraft on the Syrian Air Force. The key to this smashing tactical success was the tactic used to suppress the extensive air defense network. The Israelis used remotely piloted vehicles (RPV's) for the high-risk elements of their tactical plan. RPV's conducted in-depth reconnaissance to spot and fingerprint the search and fire control radars in the valley and on adjacent mountainsides and to locate surface-to-air missile (SAM) launch sites. When the attack started, the first waves were RPV's configured to appear as attack aircraft and draw first fire. As the engagement started, manned attack fighter-bombers used antiradiation missiles (ARM's) and other smart ordnance to destroy enemy radars and launch sites as they were engaging the RPV's. While there was some loss of the low-cost RPV's, there were no losses to the Israeli aircraft. A "hornet's nest" of weapons and radars had been effectively neutralized without loss and in a period of a few hours. Recent statements of current U.S. Naval doctrine [1] emphasize a forward area strategy of naval action in or near enemy waters. The Soviet Navy in turn has been attributed as having a "bastion" strategy [2] to operate their SLBM force in Arctic waters and heavily defend the sea approaches to these waters. In other words, we postulate that they will create a "hornet's nest" and the U.S. Navy would intend to attack it, a Naval "Bekka Valley." This article examines the potential need for unmanned systems in the execution of the forward-area strategy. Emphasis is upon medium- and long-range submersibles capable of autonomous operation. 相似文献
10.
Naoto Iwasaka Yuichi Isozaki Susumu Kuwashima Hirotaka Otobe Kimio Hanawa 《Journal of Oceanography》2000,56(6):717-726
In situ observation of downward solar radiation in the Western Pacific were carried out with voluntary merchant ships for five years from autumn 1990 through autumn 1995. Daily means of the short wave radiation were computed from the observed solar radiation. Then, the effects of shadows of the ship's superstructures on the observed radiation were corrected if needed. A 5-year average of short wave radiation along the main sea-lanes in the Western Pacific was calculated based on the observed daily mean solar radiation. Maximum values of 270–280 Wm–2 are found around 15°–20°N in May and June, while those of 290 Wm–2 are observed south of 18°S in November and December along the lanes. Small annual variations are found in the equatorial region. Annual mean values at the equator are about 230 Wm–2 between New Guinea and Indonesia, and 200 Wm–2 east of New Guinea. The 5-year average of short wave radiation was compared with the climatologies given in previous studies. We have concluded that some of results of previous studies are significantly underestimated. 相似文献
11.
The paper presents a discussion of the ventilation inception and air drawing prediction of ships propellers, aiming to predict under what conditions ventilation will happen, and the actual physical mechanism of the ventilation.Three different types of ventilation inception mechanisms are included in our discussion: free surface vortex ventilation, ventilation by sucking down the free surface without forming a vortex as well as ventilation by propeller coming out of the water. Ventilation prediction is based on a series of model tests, where the propeller is tested in different levels of intermittent ventilation. The use of underwater video gives a visual understanding of the ventilation phenomena.Ventilation by vortex formation has analogies with other phenomena, such as the inlet vortex in pump sumps, ground vortex at the inlet of the aircraft engines and the Propeller Hull Vortex Cavitation (PHVC). The paper includes comparison between Propeller Hull Vortex Cavitation (PHVC) and Propeller Free Surface Vortex Ventilation (PFSVV) as well as comparison between PFSVV and vortex formations of aero engines during high power operation near a solid surface.Experimental data based on several different model tests shows the boundary between the vortex forming, non-vortex forming and free surface ventilation flow regimes. For comparison the following parameters, which determined the intensity of the hydrodynamic interaction between the propeller and free surface have been used: propeller load coefficient cT, tip clearance ratio c/D, propeller submergence ratio h/R, ambient velocity Vi and flow cavitation/ventilation number σcav/σvent. 相似文献
12.
M.J. Broom 《Estuarine, Coastal and Shelf Science》1982,15(2):135-150
An assessment of community composition and the functional roles of the dominant species has been carried out in two intertidal areas of Malaysian mudflat dominated by natural populations of the arcid bivalve mollusc Anadara granosa.In addition to A. granosa, organisms of numerical importance are the venerid bivalve Pelecyora trigona, the neogastropod Plicarcularia leptospira, the mesogastropods Stenothyra glabrata and Cerithidea cingulata and the hermit crab Diogenes sp. The mesogastropod Natica maculosa and the neogastropod Thais carinifera may be of some importance to community organization but they are not numerically dominant. Annelids are conspicuous by their absence.The following trophic roles are ascribed to specific members of the community: A. granosa—facultative surface deposit feeder; P. trigona—suspension feeder; P. leptospira—scavenger; C. cingulata—deposit feeder/grazer; S. glabrata—deposit feeder/grazer; N. maculosa—predator; T. carinifera—predator; Diogenes sp.—scavenger/predator. S. glabrata is of particular interest because it appears to fill the niche occupied by mud snails of the genus Hydrobia in temperate mudflat systems.There is evidence of seasonality on the mudflats which points to a spawning of certain forms triggered by the major annual salinity depression at the time of the onset of the north-east monsoon in October/November. Concentrations of benthic chlorophyll a show no obvious signs of a seasonal fluctuation and the seasonality of the primary consumers is not thought to be related to food abundance. However there is some evidence of seasonality of reproduction in N. maculosa which preys on the seasonally reproducing bivalves. 相似文献
13.
The tremendous increase in offshore operational activities demands improved wave forecasting techniques. With the knowledge of accurate wave conditions, it is possible to carry out the marine activities such as offshore drilling, naval operations, merchant vessel routing, nearshore construction, etc. more efficiently and safely. This paper describes an artificial neural network, namely recurrent neural network with rprop update algorithm and is applied for wave forecasting. Measured ocean waves off Marmugao, west coast of India are used for this study. Here, the recurrent neural network of 3, 6 and 12 hourly wave forecasting yields the correlation coefficients of 0.95, 0.90 and 0.87, respectively. This shows that the wave forecasting using recurrent neural network yields better results than the previous neural network application. 相似文献
14.
Evaluation of ADEOS-II GLI ocean color atmospheric correction using SIMBADA handheld radiometer data
Hajime Fukushima Mitsuhiro Toratani Hiroshi Murakami Pierre-Yves Deschamps Robert Frouin Akihiko Tanaka 《Journal of Oceanography》2007,63(3):533-543
The performance of the “version 2” Global Imager (GLI) standard atmospheric correction algorithm, which includes empirical
absorptive aerosol correction and sun glint correction, was evaluated using data collected with handheld above-water SIMBADA
radiometers during 23 cruises of opportunity (research vessels, merchant ships), mostly in the North Atlantic and European
seas. A number of 100 match-up data sets of GLI-derived and SIMBADA-measured normalized water-leaving radiance (nL
W
) and aerosol optical thickness (AOT) were sorted out, using objective selection criteria, and analyzed. The Root-Mean-Square
(RMS) difference between GLI and SIMBADA nL
W
was about 0.32 μW/cm2/nm/sr for the 412 nm band, showing improvement by 30% in RMS difference with respect to the conventional “version 1” GLI
atmospheric correction algorithm, and the mean difference (or bias) was reduced significantly. For AOT, the RMS difference
was 0.1 between GLI estimates and SIMBADA measurements and the bias was small (a few 0.01), but the ?ngstr?m exponent was
systematically underestimated, by 0.4 on average, suggesting a potential GLI calibration offset in the near infrared. The
nL
W
differences were not correlated to AOT, although performance was best in very clear conditions (AOT less than 0.05 in the
865 nm band). Despite the relatively large scatter between estimated and measured nL
W
, the derived chlorophyll-a concentration estimates, applying the same ratio algorithm (GLI OC4V4) to GLI and SIMBADA, were
consistent and highly correlated in the range of 0.05–2 μg/l. The large variability in chlorophyll-a concentration estimate
for clear clean water areas (e.g. with the concentration range lower than about 0.05 μg/l) turns out to be due to the nature
of the “band ratio” based in-water algorithm. 相似文献
15.
《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(26):2928-2935
Iron could play a key role in controlling phytoplankton biomass and productivity in high-nutrient, low-chlorophyll regions. As a part of the iron fertilization experiment carried out in the western subarctic Pacific from July to August 2004 (Subarctic Pacific iron Experiment for Ecosystem Dynamics Study II—SEEDS II), we analysed the concentrations of trace gases in the seawater for 12 d following iron fertilization. The mean concentrations of chlorophyll a in the mixed layer (5–30 m depth) increased from 0.94 to 2.81 μg L–1 for 8 d in the iron patch. The mean concentrations of methyl bromide (CH3Br; 5–30 m depth) increased from 6.4 to 13.4 pmol L–1 for 11 d; the in-patch concentration increased relative to the out-patch concentration. A linear correlation was observed between the concentrations of 19′-hexanoyloxyfucoxanthin, which is a biomarker of several prymnesiophytes, and CH3Br in the seawater. After fertilization, the air–sea flux of CH3Br inside the patch changed from influx to efflux from the ocean. There was no clear evidence for the increase in saturation anomaly of methyl chloride (CH3Cl) due to iron fertilization. Furthermore, CH3Cl fluxes did not show a tendency to increase after fertilization of the patch. In contrast to CH3Br, no change was observed in the concentrations of bromoform (in-patch day 11 and out-patch day 11: 1.7 and 1.7 pmol L–1), dibromomethane (2.1 and 2.2 pmol L–1), and dibromochloromethane (1.0 and 1.2 pmol L–1, respectively). The concentration of isoprene, which is known to have a relationship with chlorophyll a, did not change in this study. The responses of trace gases during SEEDS II differed from the previous findings (in situ iron enrichment experiment—EisenEx, Southern Ocean iron experiment—SOFeX, and Subarctic Ecosystem Response to Iron Enrichment Study—SERIES). Thus, in order to estimate the concomitant effect of iron fertilization on the climate, it is important to assess the induction of biological activity and the distributions/air–sea fluxes of trace gases by iron addition. 相似文献
16.
The article presents initial ideas towards a network-based approach for sea state estimation used for marine operations and other maritime applications. In principle, all available means, ranging from in situ buoys, fleet of ships to remote sensing by satellite and aircraft, could be considered, emphasising that each means and any combinations among may act simultaneously. This study focuses on just one of the means; the use of ships as sailing wave buoys. The article introduces the wave buoy analogy, i.e. ship-as-a-wave-buoy, and it makes a proposal on how to impose (different) weights to the single ship-specific wave spectrum estimates obtained from multiple ships. Moreover, the work includes a discussion about the importance to associate a measure to reflect the (un)certainty of the wave spectrum estimate. The article presents a numerical case study, where multiple ships act simultaneously as wave spectrum-estimators. The case study relies on numerical motion simulations, as appropriate full-scale data is not yet available. In the analysis, it is shown that the use of simultaneous data from multiple ships leads to more accurate wave spectrum estimations. 相似文献
17.
《Marine Policy》2013
This paper investigates the effects of fuel subsidies and value added tax refunds on the operation of two types of firms associated with the jumbo squid (Dosidicus gigas) fishery in Mexico: (a) firms with ships that catch shrimp and squid in different periods of the year and (b) firms that deploy outboard-motor boats to catch squid year-round. The cost-benefit ratios of the policies are analyzed for 2008–2015, both with and without subsidy-related income. Additionally, the net cash surplus is calculated. The elimination of subsidies may affect jobs related to vessel operations in the squid fishery and may also encourage the voluntary retirement of shrimp ships. This effect is less evident in the case of the smaller boats. Strategies aimed at improving the landed squid prices are nonetheless suggested. 相似文献
18.
Maintenance and repair at the operational level is a critical function to comply with the standard of competence for officers in charge of an engineering watch in a manned/unmanned ship engine room. The human factor in ship maintenance especially deals with fulfilling of the required competency about dismantling, inspecting, repairing and reassembling equipment in accordance with manuals and good practice stated in STCW Code, as amended in 2010. This study extends the shipboard operation human reliability analysis (SOHRA) through the marine auxiliary machinery maintenance operations. The approach involves the determined marine-specific error producing conditions (EPC) and generic task type parameters to quantify generic error probability (GEP) values along with the subtasks of the maintenance operation. To acquire the EPC and GEP values, the real case study on heavy fuel oil (HFO) purifier overhauling considers different operating conditions on-board selected five ships in a dry bulk fleet. The case study shows that human error probability (HEP) values of tasks in maintenance operation change in regard to ship operating conditions. Consequently, the study contributes to the marine engineering field in improving the human factor in ship repair and maintenance operations. This approach is further extended by incorporating maintenance 4.0 requirements into ship operating environment to conduct scenario-based task analysis. 相似文献
19.
Ship sources of ambient noise 总被引：2，自引：0，他引：2
The rapid increase in world shipping results in an increase in low-frequency ambient noise at an average rate of about 1/2 dB per year. During the past 10 years there has been a virtual revolution in the sizes and speeds of merchant ships, resulting in significant increases in the noise radiated by the average ship. This trend is continuing. In this paper, the trends in world merchant shipping will be presented, including important changes in propulsion plants as well as in numbers and sizes of ships. The need for radiated noise measurements of these new ship types will be stressed. Ambient noise is also dependent on the geographical distribution of shipping. The LRAPP-sponsored program to establish standard shipping distributions for the Northern Hemisphere will be discussed, and the reliability of current information will be assessed. 相似文献
20.
M. V. Kurgansky 《Izvestiya Atmospheric and Oceanic Physics》2013,49(5):479-484
Two results that are fundamentally different from what takes place in a dry atmosphere have been obtained for adiabatic motions of unsaturated moist air: (1) the steady helical motion of moist air with collinear velocity and vorticity vectors everywhere is dynamically impossible; (2) the spontaneous amplification (generation) of helicity in a moist air due to baroclinicity is dynamically and thermodynamically feasible. In the absence of helicity flux through the boundary of the domain occupied by air flows, the difference between the values of integral helicity H at time instant t delaying at a small time interval from the initial instant t 0 (at which the instantaneous state of air motion is isomorphic either to a steady Beltrami flow or to an irrotational flow) and the initial value of H increases proportionally to (t ? t 0)4. The nonzero value of the proportionality factor is ensured by the difference in values of the Poisson ratio for dry air and water vapor, respectively. 相似文献