首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Plastics on the Sargasso sea surface   总被引:3,自引:0,他引:3  
Plastic particles, in concentrations averaging 3500 pieces and 290 grams per square kilometer, are widespread in the western Sargasso Sea. Pieces are brittle, apparently due to the weathering of the plasticizers, and many are in a pellet shape about 0.25 to 0.5 centimeters in diameter. The particles are surfaces for the attachment of diatoms and hydroids. Increasing production of plastics, combined with present waste-disposal practices, will undoubtedly lead to increases in the concentration of these particles. Plastics could be a source of some of the polychlorinated biphenyls recently observed in oceanic organisms.  相似文献   

2.
It is difficult to estimate the area affected by an oil spill at sea, the degree of coverage by oil pollutants within the affected area, and the quantity of pollutants involved. Estimates of volumes and flow rates are based on estimated changes in areal extent of the spill. Uncertainties in measurement of area degrade the accuracy of estimating other parameters. To resolve this problem, available stock components have now been assembled into a system that yields repeatable, economical measurement of the areal extent of oil spills at acceptable levels of accuracy. The system comprises overflights with a thermal infrared imaging system, densitometric color enhancement of the infrared images, and automatic digital planimetry of the areas of specified image densities.  相似文献   

3.
胡彬 《安徽农业科学》2008,36(10):4198-4199
利用国际石油市场的数据对油价波动进行实证分析。由于市场供求结构发生了长期性的改变,以垄断市场结构或竞争型市场结构来解释油价波动的方法难以得到实际数据的支持,而经济结构上的内在变化才能使油价波动形态发生根本性的变化。  相似文献   

4.
Satellite measurements of sea surface temperature through clouds   总被引:5,自引:0,他引:5  
Measurements of sea surface temperature (SST) can be made by satellite microwave radiometry in all weather conditions except rain. Microwaves penetrate clouds with little attenuation, giving an uninterrupted view of the ocean surface. This is a distinct advantage over infrared measurements of SST, which are obstructed by clouds. Comparisons with ocean buoys show a root mean square difference of about 0.6 degrees C, which is partly due to the satellite-buoy spatial-temporal sampling mismatch and the difference between the ocean skin temperature and bulk temperature. Microwave SST retrievals provide insights in a number of areas, including tropical instability waves, marine boundary layer dynamics, and the prediction of hurricane intensity.  相似文献   

5.
根据2006年1-6月中国鱿钓船在西南大西洋的生产统计和表面水温(SST)、海面高度距平值(SSHA)的资料,利用海洋地理信息系统软件Marine explorer 4.0绘制了各月产量、日产量与SST和SSHA的关系图,推测出各月渔场的最适SST和SSHA值,并经K-S检验.结果表明:1-3月中心渔场主要分布在45°S、60°W附近海域,各月最适SST分别为11~12℃、12~13℃、12~13℃;4-6月中心渔场主要分布在420S、58°W附近海域,各月最适SST分别为11~13℃、9~11℃、8~9℃.中心渔场主要分布在SSHA=0附近海域.中心渔场分布与SST和SSHA关系极为密切,可作为渔情分析指标.  相似文献   

6.
Chlorinated hydrocarbons in the Sargasso sea atmosphere and surface water   总被引:2,自引:0,他引:2  
Polychlorinated biphenyls (PCB), DDT, and chlordane concentrations were measured in air sampled from a tower on the south shore of Bermuda and in Sargasso Sea surface water approximately 80 to 320 kilometers south of Bermuda. The atmospheric chlorinated hydrocarbons appeared to be gaseous, and the DDT concentration was two orders of magnitude higher than previously reported particulate values. The PCB and DDT were enriched in the surface microlayer (150 micrometers) relative to their concentrations in water at a depth of 30 centimeters. Atmospheric residence times for PCB and DDT of 40 to 50 days, calculated from the concentrations in the air and water, are 20 times shorter than values previously estimated for DDT from rainfall and DDT production data.  相似文献   

7.
Organogenic elements, mainly carbon, nitrogen, phosphorus, and sulfur are present in the particulate material and in a breccia rock from Tranquillity Base in amounts ranging from 5 to 4200 parts per million. The major compounds of carbon released by heating are carbon monoxide and carbon dioxide; the former predominates. Small amounts of other compounds of carbon have also been observed. Sulfur can be released as hydrogen sulfide by treatment with acid. The carbon isotopic delta(13L)C values are definitely nonterrestrial (+ 13 to + 18.5 per mil).  相似文献   

8.
根据1990—2001年中西太平洋海域(20°N25°S,175°W以西)鲣Katsywonus pelamis围网作业产量和作业频次,结合海水表面温度(SST)数据,以高产频次的相对比值表示栖息地适应指数(HSI),采用3种方法建立HSI-SST模型。根据建立的3个模型,利用1990—2001年各月HSI值与实际作业产量进行比较,以选择最优HSI-SST模型;最后,利用2003年SST数据计算其各季度HSI值,用来验证预测中心渔场的可行性。结果表明:采用模型A时,主要产量分布在HSI>0.4的区域;采用模型B时,主要产量分布在HSI>0.6的区域;采用模型C时,主要产量分布在HSI>0.8的区域,因此认为模型C更符合鲣资源分布的特征。利用模型C估算2003年各季度HIS值,高产主要分布在HSI>0.8的区域,这进一步说明,模型C能较为准确地预报鲣中心渔场的位置。  相似文献   

9.
基于蒙特卡洛方法的集鱼灯海面照度模型建立   总被引:1,自引:1,他引:0  
集鱼灯照度分布计算和模拟是研究灯光渔船集鱼灯合理布置的重要途径。利用海表面风速、相对湿度数据、集鱼灯参数、渔船参数,在分析光子传输特性的基础上,运用蒙特卡洛方法建立灯光渔船集鱼灯海面照度模型。该模型利用米氏散射计算相对湿度与海表面风速对光子的吸收和散射,并考虑光子进入水面时海表风速对菲涅尔反射的影响。研究模型与叠加法比较,结果表明,该模型的理论计算值与实测值线性拟合斜率系数更接近1。计算不同风速及相对湿度的海面照度,结果表明:照度随着与船中线距离的增大而先增大后减小;相对湿度一定,随着与船中线距离的增加,先是风速越大照度越大,随后风速越大照度越小;风速一定,相对湿度对海面照度影响较小。本研究旨在建立一种集鱼灯海面照度模型,为今后灯光配置研究提供理论基础。  相似文献   

10.
太平洋褶柔鱼(Todarodes pacificus)是重要的大洋性经济头足类资源,其资源变动极易受海洋环境的影响。将影响太平洋褶柔鱼种群变动的内禀自然增长率(intrinsic natural growth rate,r)、最大环境容纳量(carrying capacity,K)与海表面温度(sea surface temperature, SST)结合起来,分别构建4种剩余产量模型(模型1、模型2、模型3、模型4),研究SST影响下的太平洋褶柔鱼种群资源变动情况。结果表明,其中加入环境因子的3种资源评估模型(模型2、模型3、模型4)的偏差信息准则(DIC)的值均小于传统的剩余产量模型(模型1)的DIC值,且以模型4的DIC值最小(132.6),表明该模型评估效果较好。研究认为,2007—2018年,太平洋褶柔鱼的捕捞死亡率Ft普遍低于最大可持续产量(maximum sustainable yield, MSY)水平的捕捞死亡率FMSY,其捕捞产量普遍低于最大可持续产量MSY。目前太平洋褶柔鱼冬生种群资源状况受环境影响较大,建议有必要留意因...  相似文献   

11.
基于表温的中西太平洋鲣栖息地适应指数的研究   总被引:2,自引:0,他引:2  
根据1990-2001年中西太平洋海域(20°N~25°S,175°W以西)鲣Katsywonus pelamis围网作业产量和作业频次,结合海水表面温度(SST)数据,以高产频次的相对比值表示栖息地适应指数(HSI),采用3种方法建立HSI-SST模型.根据建立的3个模型,利用1990-2001年各月HSI值与实际作业产量进行比较,以选择最优HSI-SST模型;最后,利用2003年SST数据计算其各季度HSI值,用来验证预测中心渔场的可行性.结果表明:采用模型A时,主要产量分布在HSI0.4的区域;采用模型B时,主要产量分布在HSI0.6的区域;采用模型C时,主要产量分布在HSI0.8的区域,因此认为模型C更符合鲣资源分布的特征.利用模型C估算2003年各季度HIS值,高产主要分布在HSI0.8的区域,这进一步说明,模型C能较为准确地预报鲣中心渔场的位置.  相似文献   

12.
Satellite and research vessel observations of sea surface temperature during the southwest monsoon of 1979 show the development of large wedge-shaped areas of cold water along the Somali coast at both 5 degrees and 10 degrees N during June and July. The cold water associated with the large northern and southern Somali eddy systems could be traced several hundred kilometers offshore. By late August the cold wedge at 5 degrees N translated northeastward as far as 10 degrees N at speeds of 15 to 30 centimeters per second, indicating a coalescence of the systems.  相似文献   

13.
我国石油战略储备问题研究   总被引:1,自引:0,他引:1  
分析了我国石油储备现状及面临的国内外严峻形势的挑战,阐述了建立战略石油储备的必要性。认为应该借鉴国际石油储备经验,有计划地建立我国的石油储备制度,分步建立和完善符合我国国情的石油储备体系。  相似文献   

14.
基于AMSR-E与MODIS数据海表面温度遥感反演研究   总被引:1,自引:0,他引:1  
海洋表面温度是海洋环境的重要参数。遥感技术是进行海表面温度研究的有效手段之一。以印度洋北部海域为研究区域,利用Aqua卫星上的微波数据(AMSR-E)和光学数据(MODIS),进行了海表温度反演研究。首先对AMSR-E L2A数据和MODIS-L1B数据进行预处理,然后将AMSR E的各极化通道亮温数据与实测海表温度进行相关性分析,通过多元线性回归建立AMSR-E海表温度的反演模型,而MODIS海表温度则通过采用线性多通道算法得到,最后以AMSR-E亮温数据为主,MODIS海表温度数据为辅,采用多元线性回归的方法建立了海表温度反演模型。利用该模型反演印度洋北部海域海表温度,反演结果与实测数据相比,其均方根误差为0.323 97 ℃。  相似文献   

15.
Lea DW  Pak DK  Spero HJ 《Science (New York, N.Y.)》2000,289(5485):1719-1724
Magnesium/calcium data from planktonic foraminifera in equatorial Pacific sediment cores demonstrate that tropical Pacific sea surface temperatures (SSTs) were 2.8 degrees +/- 0.7 degrees C colder than the present at the last glacial maximum. Glacial-interglacial temperature differences as great as 5 degrees C are observed over the last 450 thousand years. Changes in SST coincide with changes in Antarctic air temperature and precede changes in continental ice volume by about 3 thousand years, suggesting that tropical cooling played a major role in driving ice-age climate. Comparison of SST estimates from eastern and western sites indicates that the equatorial Pacific zonal SST gradient was similar or somewhat larger during glacial episodes. Extraction of a salinity proxy from the magnesium/calcium and oxygen isotope data indicates that transport of water vapor into the western Pacific was enhanced during glacial episodes.  相似文献   

16.
Initial results from the Seasat scanning multichannel microwave radiometer indicate that the sea surface temperature can be measured with a root-mean-square sensitivity of 1.2 degrees C or better. The first microwave map of sea surface temperature for the entire Pacific has been produced.  相似文献   

17.
The Paleocene-Eocene Thermal Maximum (PETM) has been attributed to a rapid rise in greenhouse gas levels. If so, warming should have occurred at all latitudes, although amplified toward the poles. Existing records reveal an increase in high-latitude sea surface temperatures (SSTs) (8 degrees to 10 degrees C) and in bottom water temperatures (4 degrees to 5 degrees C). To date, however, the character of the tropical SST response during this event remains unconstrained. Here we address this deficiency by using paired oxygen isotope and minor element (magnesium/calcium) ratios of planktonic foraminifera from a tropical Pacific core to estimate changes in SST. Using mixed-layer foraminifera, we found that the combined proxies imply a 4 degrees to 5 degrees C rise in Pacific SST during the PETM. These results would necessitate a rise in atmospheric pCO2 to levels three to four times as high as those estimated for the late Paleocene.  相似文献   

18.
The (14)C activity of dissolved organic carbon (DOC) can be used to distinguish between the fossil organic carbon due to petrochemical effluents and modern organic carbon due to domestic wastes and natural decaying organic matter. Rivers polluted by petrochemical effluents show varying amounts of depression of the DOC (14)C activity, reflecting concentrations of (14)C-deficient fossil carbon of as much as about 40 percent of the total DOC.  相似文献   

19.
Peruvian sea catfish (Galeichthys peruvianus) sagittal otoliths preserve a record of modern and mid-Holocene sea surface temperatures (SSTs). Oxygen isotope profiles in otoliths excavated from Ostra [6010 +/- 90 years before the present (yr B.P.); 8 degrees 55'S] indicate that summer SSTs were approximately 3 degrees C warmer than those of the present. Siches otoliths (6450 +/- 110 yr B.P.; 4 degrees 40'S) recorded mean annual temperatures approximately 3 degrees to 4 degrees C warmer than were measured under modern conditions. Trophic level and population diversity and equitability data from these faunal assemblages and other Peruvian archaeological sites support the isotope interpretations and suggest that upwelling of the Peru-Chile current intensified after approximately 5000 yr B.P.  相似文献   

20.
张硕  马满园  代晓琳  张崇禧 《广东农业科学》2012,39(12):106-108,121
为了探讨即食鲜海参加工工艺,在单因素试验的基础上,应用响应面方法设计正交试验,对鲜海参漂烫、调味、蒸煮等工艺进行优化。依据回归分析确定影响感官评价的影响因素,分析数据得出最佳加工工艺为:腌制温度21℃、腌制时间70 min、调料浓度64%,在此条件下实际测得感官评价为9.3分,符合商业无菌标准。所建立的回归方程能真实地反映腌制温度、腌制时间、腌制调料浓度对加工工艺的影响,通过优化能有效地提高生产工艺,并建立了一种生产软包装即食海参的新工艺。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号