黄海绿潮分布年际变化特征分析

2008-2015年,连续8年在黄海海域暴发大规模绿潮,但因暴发时间、规模及漂移路径的不同,对沿海地区造成的环境影响和经济损失大不相同。本文利用EOS/MODIS卫星的多通道资料,采用NDVI算法获取绿潮信息,给出了2007年以来5-8月所有无云或少云晴朗天气下黄海海面绿潮的分布情况。黄海绿潮覆盖面积变化每年呈现单峰值分布,MODIS卫星在5月中旬至6月初首次发现绿潮,随后30~40 d内达到覆盖面积峰值,7月快速消退,8月上旬完全消失。2007年绿潮出现首年覆盖面积极低,发现绿潮时面积均未超过50 km2;2008年和2009年绿潮覆盖面积峰值分别为3 110 km2和4 075 km2,自此绿潮灾害成为新的海洋环境事件;2010-2012年绿潮暴发规模异常低值,各年覆盖面积峰值均未超过1 800 km2,但从2013年开始绿潮规模逐渐攀升,到2015年绿潮覆盖面积峰值达5 629 km2,持续可达98 d,覆盖面积和持续时间为历年之最。绿潮漂移路径可归纳分为3类:2008年和2011年绿潮主体先北向漂移越过34°30'N后,西北向垂直于岸线漂移,主要对连云港、日照和青岛造成较大影响;2009年和2012年绿潮主体先北向漂移越过35°N后,东北向平行于岸线漂移,故只有少许绿潮上岸;2010年、2013-2015年绿潮主体北向漂移至近岸后东北向沿岸漂移,对日照、青岛和荣成沿海造成大面积影响。所有年份绿潮影响范围均限于南黄海内,东侧边界最远未越过124.2°E。     

Comparison of Multimission Altimetric Sea-Surface Heights with Tide Gauge Observations in the Southern Baltic Sea

One possible technique to validate the observations of altimeter missions is the comparison with sea-surface heights measured by tide gauges. In our investigation, we compared observations of the two tide gauge stations, Sassnitz and Warnemünde, which are located at the southern coast of the Baltic Sea, with sea-surface heights obtained from the altimeter missions Geosat, ERS-1, ERS-2, and TOPEX/Poseidon. For this purpose, the compared sea-surface heights were related to a common reference system and extrapolated to a common location. GPS observations, leveling data, regional geoid information, sea-surface topography, and postglacial rebound were included in the analysis. Considering the uncertainties of all model components, a more reliable estimation of the error budget (source, type, and magnitude of the errors) was performed. The obtained absolute altimeter biases are (-243 - 32) mm for Geosat, (467 - 19) mm for ERS-1, (76 - 19) mm for ERS-2, and (13 - 18) mm for TOPEX.     

光电码盘式验潮仪的设计

光电码盘式验潮仪采用高性能的光电码盘取代传统的机械码盘,是一种高可靠性、高准确度、实时的全量程潮位观测系统。文中对该仪器的工作原理、组成、主要技术指标、特点以及实现方法作了概要描述。     

An Improved Calibration of Satellite Altimetric Heights Using Tide Gauge Sea Levels with Adjustment for Land Motion

Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data.     

Distribution of 9 Principal Tidal Constituents and Tide Prediction for the East China Sea

By use of the hydrodynamic model,the harmonic constants of 8 principal tidal constituents(Q_1,O_1,P_1,K_1,N_2,M_2,S_2andK_2)are obtained for the East China Sea,and the harmonic constant ofS_a is calculated by two-dimensional interpolation.The calculated results agree well with the observed dataaround the sea.The harmonic constants can be used to predict the tide in the East China Sea.The cotidalcharts of the 9 tidal constituents reveal their distribution.     

Recent improvements to the physical model of the Bohai Sea,the Yellow Sea and the East China Sea Operational Oceano-graphy Forecasting System

In order to satisfy the increasing demand for the marine forecasting capacity, the Bohai Sea, the Yellow Sea and the East China Sea Operational Oceanography Forecasting System (BYEOFS) has been upgraded and improved to Version 2.0. Based on the Regional Ocean Modeling System (ROMS), a series of comparative experiments were conducted during the improvement process, including correcting topography, changing sea surface atmospheric forcing mode, adjusting open boundary conditions, and considering atmospheric pressure correction. (1) After the topography correction, the volume transport and meridional velocity maximum of Yellow Sea Warm Current increase obviously and the unreasonable bending of its axis around 36.1°N, 123.5°E disappears. (2) After the change of sea surface forcing mode, an effective negative feedback mechanism is formed between predicted sea surface temperature (SST) by the ocean model and sea surface radiation fluxes fields. The simulation errors of SST decreased significantly, and the annual average of root-mean-square error (RMSE) decreased by about 18％. (3) The change of the eastern lateral boundary condition of baroclinic velocity from mixed Radiation-Nudging to Clamped makes the unreasonable westward current in Tsushima Strait disappear. (4) The adding of mean sea level pressure correction option which forms the mean sea level gradient from the Bohai Sea and the Yellow Sea to the western Pacific in winter and autumn is helpful to increasing the fluctuation of SLA and outflow of the Yellow Sea when the cold high air pressure system controls the Yellow Sea area.     

东海对马暖流水来源的数值模拟

本文通过二维数值模拟对1986年6月～1988年12月东海对马暖流水的来源问题进行了初步探讨,结果得出东海对马暖流水的来源基本上分为三种类型:(1)东海对马暖流水主要为东海黑潮水继续北上部分构成;(2)东海对马暖流水由东海黑潮水、东海陆架水以及东海北部黄海大陆沿岸水几部分混合而成;(3)东海对马暖流水几乎全部由东海北部的黄海大陆沿岸水构成。模拟与实测结果基本一致.     

中国历代灾害性海潮的特点、成因及防治措施

本文以《中国历代灾害性海潮史料》为基础,对中国历代灾害性海潮的特点进行了初步研究,探讨了中国历代灾害性海潮随时间演进的月际和年际发生特征、主要发生类型、危害性及主要危害区域、分形性质。在此基础上,还初步探讨了灾害性海潮的成灾原因及相关防治措施。     

The Taiwan-Tsushima Warm Current System: Its Path and the Transformation of the Water Mass in the East China Sea

Using a temperature data set from 1961 to 1990, we estimated the monthly distribution of the vertically integrated heat content in the East China Sea. We then drew the monthly map of the horizontal heat transport, which is obtained as the difference between the vertically integrated heat content and the surface heat flux. We anticipate that its distribution pattern is determined mainly due to the advection by the ocean current if it exists stably in the East China Sea. The monthly map of the horizontal heat transport showed the existence of the Taiwan-Tsushima Warm Current System (TTWCS) at least from April to August. The T-S (temperature-salinity) analysis along the path of TTWCS indicated that the TTWCS changes its T-S property as it flows in the East China Sea forming the Tsushima Warm Current water. The end members of the Tsushima Warm Current water detected in this study are water masses in the Taiwan Strait and the Kuroshio surface layer, the fresh water from the mainland of China, and the southern tip of the Yellow Sea Cold Water extending in the northern part of the East China Sea. This revised version was published online in August 2006 with corrections to the Cover Date.     

东海陆架盆地瓯江凹陷古近系层序地层学与沉积特征研究

应用层序地层学方法,通过钻井、测井、地震反射等标志,识别出层序界面和最大海泛面,将东海陆架盆地瓯江凹陷古近系划分为3个层序,层序界面分别为T20、T40、T42、T50,并以地层叠置样式、岩性、岩相的变化为依据在单井上将每个三级层序细分为低位、湖侵和高位3个体系域;在层序格架内利用钻井和古生物资料分析了沉积体系在瓯江凹陷的平面展布：月桂峰组主要是三角洲相和湖泊相沉积,灵峰组和明月峰组是三角洲相和滨海相沉积,瓯江组和温州组为三角洲相和滨海相沉积,其中瓯江凹陷东次凹为浅海相沉积;沉积物源主要以西向东注入和西北方向向东南注入,同时揭示了古近系两次大规模海侵分别是古新世中期灵峰组沉积时期和始新世中期瓯江组沉积时期。     

An Improved Calibration of Satellite Altimetric Heights Using Tide Gauge Sea Levels with Adjustment for Land Motion

Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data.     

东海近海赤潮水体中酯酶活性测定及其意义

测试了东海正常海水与赤潮暴发时水体中的酯酶浓度，初步研究了营养盐的变化与酯酶浓度及其赤潮暴发的关系，发现赤潮暴发时水体的酯酶浓度大大高于正常海水，表明在赤潮暴发水体中浮游植物大量裂解死亡。     

Modeling of coupled tide–wave–surge process in the Yellow Sea

A coupled wave–tide–surge model has been developed in this study in order to investigate the effect of the interactions among tides, storm surges, and wind waves. The coupled model is based on the synchronous dynamic coupling of a third-generation wave model, WAM cycle 4, and the two-dimensional tide–surge model. The surface stress, which is generated by interactions between wind and wave, is calculated by using the WAM model directly based on an analytical approximation of the results using the quasi-linear theory of wave generation. The changes in bottom friction are created by the interactions between waves and currents and calculated by using simplified bottom boundary layer model. In consequence, the combined wave–current-induced bottom velocity and effective bottom drag coefficient were increased in the shallow waters during the strong storm conditions.     

Determination of Ocean Tide Loading Displacement by GPS PPP with Priori Information Constraint of NAO99b Global Ocean Tide Model

The published global ocean tide models show good agreement in deep oceans and exhibit differences in complex coastal areas, along with subsequent Ocean Tide Loading Displacement (OTLD) modeling differences. Meanwhile, OTLD parameters (amplitudes and phase lags) derived by Global Positioning System (GPS) Precise Point Positioning (PPP) approach need long time to converge to a stable state and show poor precision of S2, K1, and K2 constituents. Based on the fact that no constraint is imposed in the current kinematic solution, a new method is put forward, in which global ocean tide model predictions are taken as the priori information constraints to speed up the convergence rate and improve the accuracy of the GPS-derived OTLD parameters. First, the data of tide gauge from 01 January 2014 to 31 December 2016 are used to generate the harmonic parameters to evaluate the accuracy of six global ocean tide models and a regional ocean tide model (osu.chinesea.2010). Osu.chinesea.2010 model shows good agreement with the tide gauge results, while NAO99b model presents relatively large difference. The predictions from osu.chinesea.2010 and NAO99b model are employed as reference and the prior information, respectively. Second, continuous observations of 12 GPS sites during 2006–2013 in Hong Kong are collected to generate three dimensional OTLD amplitudes and phase lags of eight constituents using PPP with prior information constraints approach and harmonic analysis. Third, comparing the convergence time of eight constituents from PPP without and with priori information constraints approaches, the results show that the new method can significantly improve the convergence rate of OTLD amplitude estimates which obtain a certain level of stability seven years earlier than that derived by the PPP without priori information constraints. Precision of OTLD parameters derived by the new method is about 1 mm. By comparing with the precision of single PPP approach, the accuracy of eight constituents has been improved, especially for S2, K1, and K2 constituents. Finally, through comparing the different correction effects of OTLD estimates on the coordinates and their time series of the ground GPS stations, the results show that OTLD estimates derived by the new approach have similar influence as the osu.chinasea.2010 ocean tide model. The new method provides an effective means to improve the convergence and precision of the GPS-derived OTLD parameters, and achieve a similar correction as the high precision ocean tide model.     

Characteristics of Tide in The South China Sea

Based ourself mainly on the harmonic constant in the tide table (English-edition), we acquire data from 320 tidal observatories, calculate the different tidal ranges and cotidal hours of the South China Sea, and by the contour line method, draw the M_2, S_2. K_1, O_1 constituent charts, thus better showing the tide distribution in the South China Sea and presenting tide characteristics in the area more accurately.     

长江口外潮汐精细化模型研究与精度分析

长江口外海上测量除受风浪影响较大外,最重要的问题是潮位控制非常困难。文中简要阐述了开展长江口外潮汐精细化模型研究的方法,介绍了利用潮汐精细化模型对长江口外航路任意点进行潮汐预报的方法,并通过实测数据进行了精度分析,提出了建议。     

Trichodesmium in the East China Sea

A study is made on the surface distribution ofTrichodesmium thiebautii Gomont in the East China Sea during the years 1961–1967.

1. This alga is very scarce or absent in the period from January to March, and begins to increase in May and June, reaching the maximum population density from July to September, and again decreases in October and November.
2. In summerT. thiebautii is predominantly distributed in the area along the Kuroshio current with high densities of 10²–10³ filaments/l, occasionally exceeding 10³ filaments/l. This alga is estimated to occupy the major part or almost all the parts of chlorophylla in situ contained in the surface water of this season.
3. The occurrence ofT. thiebautii off the southern coasts of Central Japan seems to be caused rather by the multiplication in its own habitat than by the transportation by the Kuroshio current from the East China Sea.

     

Sediments in the East China Sea

This paper describes measurements of sediments during the 2000-2001 Asian Seas International Acoustic Experiment in the East China Sea. A number of techniques were used to infer properties of these sediments, including gravity and piston cores, subbottom profiling using a water gun, long-range sediment tomography, and in situ measurement of conductivity. Historical data from echosounder records and cores showed two regions of surficial sediments in the experimental area: a silty area to the west and a sandy area to the east. The tomography, cores, and water-gun measurements confirm the two surficial sediment regions seen in the historical data and also indicate that the subbottom structure at the experimental site consists of a thin (0-3 m thick) layer of sandy sediment directly beneath the sea floor. Below this layer, there is an extensive package of sediment with relatively uniform acoustic attributes. Core analysis shows that the surface sediment layer varies in compressional wave speed from a low near 1600 m/s in the west side of the experiment area to 1660 m/s in the east side of the experiment area. Long-range sediment tomography inversions show a similar spatial variation in the surface layer properties. In addition, the layer thickness as determined from tomography is consistent with the estimates from subbottom profiling.