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A new algorithm of retrieving a petroleum substances absorption coefficient in sea water based on a remote sensing image 被引量:7
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作者 HUANG Miaofen XING Xufeng +2 位作者 SONG Qingjun LIU Yang DONG Wentong 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第11期97-104,共8页
Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a ... Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a remote sensing technology. A remote sensing reflectance is a basic physical parameter in water color remote sensing. Apply it to directly retrieve the absorption coefficient of seawater petroleum substances is of potential advantage. The absorption coefficient of waters containing petroleum [ACWCP, a_o(λ)], consists of the absorption coefficient of pure water [ACPW, a_w(λ)], plankton [ACP, a_(ph)(λ)], colored scraps [ACCS, a_(d,g)(λ)], and petroleum substance [ACPS, a_(oil)(λ)]. Among those, ACCS consists of the absorption coefficient of nonalgal particle [ACNP, a_d(λ)] and colored dissolved organic matter [ACCDOM, a_g(λ)]. For waters containing petroleum, the retrieved ACCS using the existing method is a combination absorption coefficient of ACNP,ACCDOM and ACPA [CAC, a_(d,g,oil)(λ)]. Therefore, the principle question is how to extract ACPS from CAC.Through the analysis of the three proportion tests conducted between the year of 2013 and 2015 and the corresponding remote sensing data, an algorithm of retrieving the absorption coefficient of petroleum substances is proposed based on remote sensing reflectance. First of all, ACPS and CAC are retrieved from the reflectance using the quasi-analytical algorithm(QAA), with some parameter modified. Secondly, given the fact that the backscatter coefficient [BC, b_(bp)(555)] of total particles at 555 nm can be obtained completely from the reflectance, the relation between BC and ACNP in petroleum contaminated water can be established. As a result, ACNP can be calculated. Then, combining the remote sensing retrieving algorithm of a_g(440), the method of achieving the spectral slope of the absorption coefficient can be established, from which ACCDOM,can be calculated. Finally, ACPS can be computed as the residual. The accuracy of ACPS based on this algorithm is 86% compared with the in situ measurements. 展开更多
关键词 petroleum substances in sea water remote sensing technology absorption coefficient retrieval algorithm
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Preliminary study on the distribution of nutrients, organic matter, trace metals in sea surface microlayer in Xiamen Bay and Jiulong Estuary 被引量:4
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作者 Hong Huasheng and Lin Jie Department of Oceanography, Xiamen University. Xiamen, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1990年第1期81-90,共10页
The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The m... The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer. 展开更多
关键词 Preliminary study on the distribution of nutrients trace metals in sea surface microlayer in Xiamen Bay and Jiulong Estuary BAY
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Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water
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作者 Qiu Xinfang( Received May 17, 1990 accepted August 20, 1990) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1991年第2期271-280,共10页
By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatur... By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given. 展开更多
关键词 Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water ACID
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Analysis of atmospheric turbulence in the upper layers of sea fog 被引量:5
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作者 李永平 郑运霞 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第3期809-818,共10页
Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thu... Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus,the turbulence characteristics of upper fog layers are poorly known. In this paper,we present 4-layers of data,measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy,momentum flux,and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset,high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold,it was crucial to enhancing the cooling rate,and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode,the vertical distribution of sensible heat flux reversed,contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog,than during the fog episode. Turbulence energy was greatest in upper levels,around 430 m and 450 m above mean sea level(AMSL),than in lower levels of the fog(390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer,affecting the underlying fog by decreasing or increasing average wind speed,as well as promoting or demoting air temperature stratification. 展开更多
关键词 ultrasonic anemometers turbulence characteristics momentum flux sensible heat flux variation in sea fog
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Temporal and spatial variability of the carbon cycle in the east of China's seas:a three-dimensional physical-biogeochemical modeling study 被引量:1
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作者 JI Xuanliang LIU Guimei +2 位作者 GAO Shan WANG Hui ZHANG Miaoyin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第3期60-71,共12页
In the east of China's seas, there is a wide range of the continental shelf. The nutrient cycle and the carbon cycle in the east of China's seas exhibit a strong variability on seasonal to decadal time scales. On th... In the east of China's seas, there is a wide range of the continental shelf. The nutrient cycle and the carbon cycle in the east of China's seas exhibit a strong variability on seasonal to decadal time scales. On the basis of a regional ocean modeling system(ROMS), a three dimensional physical-biogeochemical model including the carbon cycle with the resolution(1/12)°×(1/12)° is established to investigate the physical variations, ecosystem responses and carbon cycle consequences in the east of China's seas. The ROMS-Nutrient Phytoplankton Zooplankton Detritus(NPZD) model is driven by daily air-sea fluxes(wind stress, long wave radiation, short wave radiation, sensible heat and latent heat, freshwater fluxes) that derived from the National Centers for Environmental Prediction(NCEP) reanalysis2 from 1982 to 2005. The coupled model is capable of reproducing the observed seasonal variation characteristics over the same period in the East China Sea. The integrated air-sea CO_2 flux over the entire east of China's seas reveals a strong seasonal cycle, functioning as a source of CO_2 to the atmosphere from June to October, while serving as a sink of CO_2 to the atmosphere in the other months. The 24 a mean value of airsea CO_2 flux over the entire east of China's seas is about 1.06 mol/(m^2·a), which is equivalent to a regional total of3.22 Mt/a, indicating that in the east of China's seas there is a sink of CO_2 to the atmosphere. The partial pressure of carbon dioxide in sea water in the east of China's seas has an increasing rate of 1.15 μatm/a(1μtm/a=0.101 325Pa), but p H in sea water has an opposite tendency, which decreases with a rate of 0.001 3 a^(–1) from 1982 to 2005.Biological activity is a dominant factor that controls the pCO_2 air in the east of China's seas, and followed by a temperature. The inverse relationship between the interannual variability of air-sea CO_2 flux averaged from the domain area and Ni?o3 SST Index indicates that the carbon cycle in the east of China's seas has a high correlation with El Ni?o-Southern Oscillation(ENSO). 展开更多
关键词 the east of China's seas physical-biogeochemical model partial pressure of carbon dioxide in sea water air-sea CO2 flux
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Slowdown of sea surface height rises in the Nordic seas and related mechanisms
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作者 SHI Wenqi ZHAO Jinping +2 位作者 LIAN Xihu WANG Xiaoyu CHEN Weibin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第8期20-33,共14页
A slowdown of sea surface height (SSH) rise occurred in the Nordic (GIN) seas around 2004. In this study, SSH satellite data and constructed steric height data for the decades before and after 2004 (i.e., May 199... A slowdown of sea surface height (SSH) rise occurred in the Nordic (GIN) seas around 2004. In this study, SSH satellite data and constructed steric height data for the decades before and after 2004 (i.e., May 1994 to April 2014) were used for comparative analysis. The findings indicate that the rate of slowdown of SSH rises in the GIN seas (3.0 mm/a) far exceeded that of the global mean (0.6 mm/a). In particular, the mean steric height of the GIN seas increased at a rate of 4.5 mm/a and then decreased at a slower pace. This was the main factor responsible for the stagnation of the SSH rises, while the mass factor only increased slightly. The Norwegian Sea particularly experienced the most prominent slowdown in SSH rises, mainly due to decreased warming of the 0-600 m layer. The controlling factors of this decreased warming were cessation in the increase of volume of the Atlantic inflow and stagnation of warming of the inflow. However, variations in air-sea thermal flux were not a major factor. In the recent two decades, mean halosteric components of the GIN seas decreased steadily and remained at a rate of 2 mm/a or more because of increased flow and salinity of the Atlantic inflow during the first decade, and reduction in freshwater inputs from the Arctic Ocean in the second decade. 展开更多
关键词 Nordic seas sea surface height steric height slowdown in sea level rises
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Sailing In Sea of Commerce
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作者 HU YUE 《Beijing Review》 2008年第4期38-39,共2页
The law of big fish swallowing little fish has expired when it comes to the era of new economy.What prevails nowadays in the sea of commerce is quick fish swallowing slow fish.In the Internet economy,small companies a... The law of big fish swallowing little fish has expired when it comes to the era of new economy.What prevails nowadays in the sea of commerce is quick fish swallowing slow fish.In the Internet economy,small companies are not destined to lose to giants,but slow ones are doomed to become prey of their quick counterparts. The swiftly rising Yongkang Group has made a breakthrough in dental treatment by translating the law into practice.It is called"Law of the Sea."‘Law of the Sea’ 展开更多
关键词 CO Sailing in sea of Commerce
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基于惯导和无时延滤波器的舰船升沉测量 被引量:15
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作者 严恭敏 苏幸君 +1 位作者 翁浚 秦永元 《导航定位学报》 2016年第2期91-93,107,共4页
在利用惯导测量舰船的升沉运动中,针对传统方法设计的高通数字滤波器存在较大的相位滞后误差(即信号处理后的时间延迟误差)问题,提出一种滤波器设计方法:通过先设计传统的无限冲激响应低通滤波器,再采用互补方法将其转换为无相位滞后的... 在利用惯导测量舰船的升沉运动中,针对传统方法设计的高通数字滤波器存在较大的相位滞后误差(即信号处理后的时间延迟误差)问题,提出一种滤波器设计方法:通过先设计传统的无限冲激响应低通滤波器,再采用互补方法将其转换为无相位滞后的高通滤波器,解决了信号时延问题;阐述了舰船升沉测量信号处理过程,即根据舰船上惯导姿态信息和加速度计采样输出,解算并给出天向加速度,通过积分和无时延高通滤波处理,获得升沉运动信息。最后,利用海上舰船试验数据进行验证,结果表明该方法的升沉测量精度提高了一个数量级。 展开更多
关键词 升沉运动测量 惯导 无时延数字滤波器 海试
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位置未知条件下惯性/星敏组合系统海上牵引启动方法 被引量:1
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作者 郭正东 赵汪洋 +2 位作者 刘伟 李晓 孙大开 《中国惯性技术学报》 EI CSCD 北大核心 2022年第3期316-321,共6页
针对地理位置未知条件下惯导系统海上启动对准实现问题,提出了基于锚泊条件的惯性/星敏组合导航系统位置未知条件下的海上牵引启动方法。建立了惯性/星敏信息的迭代滤波模型,研究了惯性/星敏牵引启动方法、分析了自主启动精度、提出了... 针对地理位置未知条件下惯导系统海上启动对准实现问题,提出了基于锚泊条件的惯性/星敏组合导航系统位置未知条件下的海上牵引启动方法。建立了惯性/星敏信息的迭代滤波模型,研究了惯性/星敏牵引启动方法、分析了自主启动精度、提出了自主启动实现方案。通过惯性基准和星敏感器联合使用,惯性基准辅助星敏感器进行观星定位,观星定位数据对惯性基准平台反馈修正,基于惯性/星敏位置和姿态信息在牵引启动下的相互校准方式,组合系统经过多次迭代修正,构造高精度水平基准,完成惯性/星敏组合系统海上位置未知条件下纬度、经度自估计,实现船舶对准后的正常航行。实验结果表明,采用所提出的惯性/星敏组合系统牵引启动方法获得的经纬度自估计精度与星敏感器的测量精度相当。 展开更多
关键词 惯性/星敏 纬度未知 海上对准 纬度估计
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船用惯性导航系统试验方法研究 被引量:8
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作者 郑梓桢 刘德耀 蔡迎波 《中国惯性技术学报》 EI CSCD 2004年第1期74-76,共3页
为应对新型惯性导航系统试验鉴定的需要,在分析船用惯性导航系统技术特点和试验要求的基础上,对其试验鉴定方法进行了探讨。提出一种海陆结合试验模式,并论述了其实施要点。
关键词 惯性导航系统 船舶导航 模拟测试系统 海陆结合试验模式 惯性敏感器 基准方向
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横门围垦对邻近海域水环境影响的数值模拟 被引量:4
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作者 万军明 李适宇 《上海环境科学》 CAS CSSCI CSCD 2000年第3期105-107,共3页
用二维水动力数值模型,模拟了横门围垦工程对邻近海域水环境的影响。计算结果表明,工程后流速的改变幅度在-10.15~+10.03cm/s之间,平均为-3.39cm/s。水位的改变幅度在-5.24~+8.85cm之间,平均为-0.16cm,大潮期间落潮最大流速时水位的... 用二维水动力数值模型,模拟了横门围垦工程对邻近海域水环境的影响。计算结果表明,工程后流速的改变幅度在-10.15~+10.03cm/s之间,平均为-3.39cm/s。水位的改变幅度在-5.24~+8.85cm之间,平均为-0.16cm,大潮期间落潮最大流速时水位的变化幅度,稍大于涨潮最大流速时的变化幅度。围垦工程完成后,邻近海域浅滩处的流速进一步降低,有利于促进淤积,加快浅滩成围速度,而深槽处的流速则略有提高,对河道泄洪没有太大影响。邻近海区水位低潮时将略有下降,高潮时将略有上升,但变化不大,最大不超过10cm,平均不到1cm。 展开更多
关键词 近海水域 潮流 数值模型 围垦工程 水环境影响
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