On a rapid method of mapping sea areas using NOAA AVHRR data

An effective method for plotting cartographical projections to solve different problems of local monitoring of sea areas is suggested using high-resolution data in the format of digital transmission HRPT derived from NOAA AVHRR.Translated by Mikhail M. Trufanov.     

气象卫星用于近海污染监测及赤潮预报方法探索

近年来，由于工农业和沿海养殖业的发展，我国近海污染逐年加重，赤潮发生频次增加。因此，监测近海污染和赤潮发生预报方法研究势在必行。本文用ＮＯＡＡ／ＡＶＨＲＲ数据，分析近海水域污染状况，并探索赤潮发生的预报方法。     

NOAA/AVHRR卫星海表温度在西北太平洋的印证及分析

本文详细分析了TeraScan系统反演NOAA/AVHRR卫星海表温度的过程,解决了反演过程中的海陆匹配问题和云检测过程中的误检、漏检问题,处理得到2002年(5°～45°N)、(105°～150°E)区域内的卫星海表温度数据.利用东北亚地区海洋观测系统NEAR-GOOS提供的现场海表温度数据做比较,印证NOAA/AVHRR海表温度在西北太平洋海域的精度,并分析其误差产生的来源.     

Spatial and Temporal Scale Variations of Sea Surface Temperature in the East Sea Using NOAA/AVHRR Data

Sea surface temperature fields in the East Sea are composed of various spatial structures such as eddies, fronts, filaments, turbulent-like features and other mesoscale variations associated with the oceanic circulations of the East Sea. These complex SST structures have many spatial scales and evole with time. Semi-monthly averaged SST distributions based on extensive satellite observations of SSTs from 1990 through 1995 were constructed to examine the characteristics of their spatial and temporal scale variations by using statistical methods of multi-dimensional autocorrelation functions and spectral analysis. Two-dimensional autocorrelation functions in the central part of the East Sea revealed that most of the spatial SST structures are anisotropic in the shape of ellipsoids with minor axes of about 90–290 km and major axes of 100–400 km. Two dimensional spatial scale analysis demonstrated a consistent pattern of seasonal variation that the scales appear small in winter and spring, increase gradually to summer, and then decrease again until the spring of the next year. These structures also show great spatial inhomogeneity and rapid temporal change on time scales as short as a semi-month in some cases. The slopes in spectral energy density spectra of SSTs show characteristics quite similar to horizontal and geostrophic turbulence. Temporal spectra at each latitude are demonstrated by predominant peaks of one and two cycles per year in all regions of the East Sea, implying that SSTs present very strong annual and semi-annual variations. This revised version was published online in August 2006 with corrections to the Cover Date.     

The estimate of sea ice resources quantity in the Bohai Sea based on NOAA/AVHRR data

The research on sea ice resources is the academic base of sea ice exploitation in the Bohai Sea. According to the ice-water spectrum differences and the correlation between ice thickness and albedo, this paper comes up with a sea ice thickness inversion model based on the NOAA/AVHRR data. And then a sea ice resources quantity (SIQ) time series of Bohai Sea is established from 1987 to 2009. The results indicate that the average error of inversion sea ice thickness is below 30%. The maximum sea ice resources quantity is about 6 × 10 9 m 3 and the minimum is 1.3 × 10 9 m 3 . And a preliminary analysis has been made on the errors of the estimate of sea ice resources quantity (SIQ).     

利用NOAA卫星AVHRR图像对渤海表层水温年变化的初步分析

利用ＮＯＡＡ卫星ＡＶＨＲＲ图像（使用１９９２～１９９４年共２２幅图像）选取渤海中的１５个特征区域进行分析。根据其年变化曲线,结合渤海的实际情况,讨论了渤海中相应海区的年变化,并且对大部分区域水温变化特征的形成机制进行一些初步的探讨。文中指出,辽西低温中心的动力机制是绕半岛潮流引起的垂直向环流的作用,而正是由于辽东半岛的特殊的地理特征,才可能产生这一明显的低温中心。冬季的黄海暖流在渤海中的作用是非常显著的,它是使冬季渤海中部及南部水温明显高于北部辽东湾水温的重要原因。上述工作证实,利用卫星图像进行海水温度年变化的分析是切实可行的,由此,应充分发挥卫星遥感技术上的优势,以加快海洋学的发展。     

Seasonal and Spatial Variations of Iceberg Drift off Dronning Maud Land, Antarctica, Detected by Satellite Scatterometers

Seasonal and spatial variations of iceberg drift were studied using continuous satellite scatterometer images off Dronning Maud Land, East Antarctica. Generally, iceberg drift speed showed a westward increase to the Greenwich Meridian. Seasonal variations of the drift speed were high in autumn—early winter and low in spring, and their magnitudes also increased westward. Seasonal variations of the drift speed were significantly correlated with variations of sea levels at Syowa and Mawson Stations, and hence qualitatively consistent with geostrophic current variations. Thus, the scatterometer data are demonstrated to be useful in monitoring iceberg trajectory and oceanic current variations. This revised version was published online in July 2006 with corrections to the Cover Date.     

利用NOAA卫星图像和水文资料研究东海水文的变化

本文利用ＮＯＡＡ卫星图像处理结果与同期水文观测资料，对东海表层水团的分布和转移特征作了初步分析。结果表明，东海表层水温的分布与结构同该海区的水团和环流发展相联系，水团消长和东海冬季高密水核心上层环流的发展可诱导长江口外混合水向外海扩散，表层水块的移动速度可达２６ｃｍ／ｓ，与动力学估算和同期漂移浮标所得的结果一致     

台湾近海水文观测体系的构建及其数据分析方法

台湾岛地处亚欧大陆和太平洋交界处,台风、东北季风等所引起的海洋灾害频繁,所以建立完备的海洋水文观测体系显得尤为重要.中国台湾自主建置完成的近海水文观测体系由资料浮标站、观测桩、潮位站、岸边气象站、雷达测波站等多种近海水文观测系统构建组成;同时,为确保观测体系的准确性和规范性,还建立了数据品质管理系统和标准化作业模式.在近海水文观测数据的分析方面,尝试应用新的数学分析方法,如通过EMD(empirical mode decomposition)方法探讨风暴潮水位变化,利用小波转换从雷达观测影像中分析近岸波浪信息,以及发展数据同化技术将观测数据应用于作业化波浪现报、预报模式.此外,近海水文观测体系在社会应用方面有着很大的发展潜质.     

Reconstruction of radiation fluxes at the ocean surface from NOAA satellite data

Algorithms for obtaining operative information on the fluxes of the total solar radiation and radiation balance at the ocean surface are developed and realized on the basis of satellite observations within the spectral ranges 0·725–1·1 and 10·3–11·3 m at arbitrary scanning angles. For the 10-day and monthly values, the reconstruction errors remain at the level of the accuracy of the shipboard measurements. The atlas of charts of the above parameters (grid 0·5°×0·5°) is compiled using data obtained by the RVAkademik Vernadsky in the Atlantic Ocean during 1986–1989.Translated by Mikhail M. Trufanov.     

Distribution of suspended particulate matter in the North Sea as inferred from NOAA/AVHRR reflectance images and in situ observations

Distribution patterns of suspended particulate matter (SPM) in the surface water of the North Sea were calculated on the basis of: (1) the 1973–1993 data base of the EC MAST North West European Shelf Programme (NOWESP); and (2) composite reflectance images constructed from data that were collected by the NOAA/AVHRR satellite in 1990–1991. Three models were used for interpolating the in situ data: (1) a distance-weighted interpolation algorithm in which only the in situ data are taken into account; (2) an algorithm in which the ratios between the measured SPM concentrations and reflectances are interpolated, and the distribution of SPM is calculated from the field of interpolated ratios and the synoptic reflectance image; and (3) a distance-weighted algorithm similar to model-1, but with an additional weight factor that is based on local differences in reflectance. The models were tested for periods of 1 and 3 weeks in September 1990 and January 1991, and for the merged set consisting of all in situ data measured in September and January, respectively, between 1973 and 1993. Model-2 and -3 gave largely similar results and had a performance superior to model-1, particularly because they showed more detailed structures in the spatial distributions. Validations and cross-validations showed that the absolute concentrations of SPM predicted by the models were too low at high in situ concentrations and too high at low in situ concentrations. This shortcoming was due to the relatively high degree of smoothing that we applied in the models to account for the large variance of the in situ data. Semivariograms and correlograms indicated that the in situ data had substantial variability and were poorly correlated even at short distances. Only for the 20-year-merged data set did some correlation ( %) exist for stations km from each other. Monthly distributions of SPM were calculated with model-3 and the 20-year data set. The distributions confirm the main patterns previously found by others, such as the turbidity plume crossing the North Sea from southeast England towards the depository in the Skagerrak and the Norwegian Channel. The distributions indicate that materials from this plume may be deposited in the central North Sea in spring and summer and eroded again in autumn and winter. Areas with maximum SPM concentrations were identified off the Belgian coast and north of the Wadden Sea, particularly in winter, from which particles are entrained into the main current in a narrow strip along the continental coast to the German Bight. The results suggest that the two main fluxes of SPM in the North Sea, off England and along the continental coast, remain largely separated until they both end in the Skagerrak.     

渤海、黄海、东海AVHRR海表温度场的季节变化特征

海表温度场表征了海洋热力、动力过程和海洋与大气相互作用的综合结果.它不仅是研究海面水汽和热量交换的一个重要物理参数,也为海洋环流、水团、海洋锋、上升流和海水混合等海洋学课题的研究提供一种直观的指示量.20世纪60年代以来,我国海洋工作者在历次海上观测和台站资料的基础上,对渤海、黄海、东海表层温度的空间分布和变化进行了较为详细的分析研究[1～4],并绘制了系列的水温气候图集.这些研究成果对认识黄海、东海海域的平均海表温度场的分布、变化以及相关物理海洋现象的研究起到了重要的作用.     

Transfer of lipids from plankton to blubber of harp and hooded seals off East Greenland

Sub-Arctic marine ecosystems are some of the most productive ecosystems in the world's oceans. The capacity of herbivorous zooplankton, such as Calanus, to biosynthesize and store large amounts of lipids during the short and intense spring bloom is a fundamental adaptation which facilitates the large production in these ecosystems. These energy-rich lipids are rapidly transferred through the food chain to Arctic seals. The fatty acids and stable isotopes from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) off East Greenland as well as their potential prey, were analysed. The results were used to describe the lipid dynamics and energy transfer in parts of the East Greenland ecosystem. Even if the two seal species showed considerable overlap in diet and occurred at relatively similar trophic levels, the fatty acid profiles indicated that the bases of the food chains of harp and hooded seals were different. The fatty acids of harp seals originate from diatom-based food chain, whereas the fatty acids of hooded seals originate from dinoflagellate and the prymnesiophyte Phaeocystis pouchetii-based food chain. Stable isotope analyses showed that both species are true carnivores on the top of their food chains, with hooded seal being slightly higher on the food chain than harp seal.     

Structure of the Sunda Trench lower slope off sumatra from multichannel seismic reflection data

Multichannel seismic reflection profiles across the Sunda Trench slope off central Sumatra reveal details of subduction zone structure. Normal faults formed on the outer ridge of the trench offset deep strate and the oceanic crust, but die out upsection under the trench sediments. At the base of the inner trench slope, shallow reflectors are tilted seaward, while deeper reflectors dip landward parallel to the underlying oceanic crustal reflector. Intermediate depth reflectors can be traced landward through a seaward-dipping monocline. We interpret this fold as the shallow expression of a landward-dipping thrust fault at depth. Landward of this flexure, relatively undeformed strata have been stripped off the oceanic plate, uplifted 700 meters, and accreted to the base of the slope. The oceanic crust is not involved in the deformation at the toe of the slope, and it can be observed dipping landward about 25 km under the toe of the accretionary prism.The middle portion of the trench slope is underlain by deformed accreted strata. Shallow reflectors define anticlinal structures, but coherent deep reflectors are lacking. Reflectors 45 to 55 km landward of the base of the slope dip 4°-5° landward beneath a steep slope, suggesting structural imbrication.A significant sediment apron is absent from the trench slope. Instead, slope basins are developed in 375–1500 m water depths, with an especially large one at about 1500 m water depth that is filled with more than 1.1 seconds of relatively undeformed sediments. The seaward flank of the basin has recently been uplifted, as indicated by shallow landward-dipping reflectors. Earlier periods of uplift also appear to have coincided with sedimentation in this basin, as indicated by numerous angular unconformities in the basin strata.Contribution of the Scripps Institution of Oceanography, new series.     

Surface circulation in the southwestern Japan/East Sea as observed from drifters and sea surface height

The mean circulation of the surface layer of the southwestern Japan/East Sea (JES) was examined using current measurements collected at 15 m by satellite-tracked drifters and merged sea level anomalies from satellite altimeters. The study of circulation patterns in this paper focused on the inflow passing through the western channel of the Korea Strait from the East China Sea. Empirical Orthogonal Function (EOF) analysis of non-seasonal sea level anomalies revealed that significant energy in the circulation pattern of Ulleung Basin was controlled by the inflow conditions through the Korea Strait. Three circulation patterns were identified that depended on the initial relative vorticity of the inflow. When inflow had initially large negative vorticity, the flow gained more negative vorticity due to deepening of the bottom (stretching) and then turned right after entering the JES. The inflow then followed the path of the Tsushima Warm Current along the coast of Japan. When the inflow was strong, with a speed in excess of 55 cm/s and with a large positive vorticity, potential vorticity appeared to be conserved. In this case, the EKWC followed isobaths along the coast and then left the coast, following topographic features north of Ulleung-Do. The northward flowing jet developed inertial meandering after leaving the coast, which is a characteristic of many western boundary currents. The regular, bimonthly deployments of drifters in the western portion of the Korea Strait revealed that splitting or branching of the flow through the western channel of the Korea Strait occurred only 15% of the time. And splitting or branching rarely occurred during the fall and winter seasons, when the inflow splitting was previously reported in hydrographic surveys. The time-averaged circulation map of the EKWC and its seaward extension were considerably enhanced by using regularly sampled geostrophic velocities calculated from sea level anomalies to remove biases in the mean velocity that were caused by irregular spatial and temporal drifter observations. The East Korean Warm Current, a mean coastal current along the Korean coast, behaved like the simple model by Arruda et al. (2004) in which the generation of the Ulleung Warm Eddy and the meandering circulation pattern were well reproduced.     

Retrieving the surface axis of the Kuroshio off southern coast of Japan from SST data

1IntroductionThe remarkable shape of the axis of the Kuro-shio revealed by a simple zig-zag bathythermographwas surveyed in1965(Stommel,1972).This sur-vey revealed that the15℃isotherm at the200mdepth is indicative of the axis of the Kuroshio,and ithas be…     

南海北部陆坡气泡羽状流的发现:多波束水体数据

利用2016年在南海西北部陆坡琼东南海域采集的多波束水体数据,发现了海底气体渗漏至海水中形成的羽状流。在多波束数据上, 羽状流成火焰状,直径大约为30~50 m,从1 380多米的海底延伸至大约650 m的深度,高度超过700 m。在经过羽状流的浅剖剖面上,存在显示浅层气存在的声学空白区域,并识别出断裂和裂隙区域,但在水体中并无明显的异常。这可能是由于浅剖数据的分辨率不够未能捕捉到水体异常,或者气体渗漏具有间歇性。该海域存在明显的似海底反射显示,气体渗漏可能与水合物系统之间存在复杂的相互作用。由于缺乏经过羽状流的多道地震数据,难以对羽状流的形成机制进行进一步的推测。南海北部陆坡羽状流的发现对于理解被动大陆边缘的甲烷渗漏机制、水合物的形成与分解具有重要的意义。