利用T/P海面高度数据校验验潮站地面升降的初步研究

利用TOPEX/Poseidon卫星1993—2001年的海面测高资料提取了上海和江苏临近海域这9年间的绝对海面变化信息，并与该区域6个验潮站的同时段潮位记录数据进行了对比分析。研究结果表明根据T/P海面高度数据提取的月均海面变化曲线与同海区验潮站测得的同期海面变化过程具有相当好的一致性和同步性，但是根据潮位序列得出的9年平均海面上升速率值均大于根据卫星资料得出的上升速率值。由于卫星测高数据是严格建立在地心坐标基础上的，因此二者的差异在很大程度上应与验潮站所在地点的地面沉降有关。值得注意的是经过地面沉降校正的上海吴淞验潮站数据得出的9年平均海面上升速率值仅比卫星测高结果大0. 43 mm/a，而江苏省射阳河口至三条巷之间5个未经地面沉降校正的验潮站得出海面上升速率与卫星测高结果之间的差值在0.95～3.01 cm/a之间，并呈向北递增趋势。这一对比结果反映该岸段近期的地面沉降速率可能有自南向北增大的趋势，其量值有可能达到年厘米量级。     

长江口潮位变化对潮型影响的研究

利用代表潮位站吴淞站19752010年实测资料,分析了长江口潮位变化对潮型的影响。研究结果表明,随着年平均潮位的上升,代表站年平均高（低）潮位会相应抬升,二者线性相关关系非常密切,而潮差、潮历时与年平均潮位的相关关系不明显。另外,年最高（低）高（低）潮位、年最大涨（落）潮潮差、年最大（小）涨（落）潮历时等各项极值与年平均潮位变化也没有明显的相关关系。     

中国近海海面地形的计算与研究

介绍了海面地形的研究现状,并根据几何水准求得了中国近海的海平面倾斜及其精度.给出应用水文资料计算中国近海海面地形的公式及其计算结果.探讨了由球函数模型计算中国近海海面地形的理论和方法,并对不同方法进行了比较,得出了一些有益的结论.     

基于卫星高度计的全球大洋潮汐模式的准确度评估

依据152个深海验潮站与大洋岛屿地面验潮站观测得到的8个主要分潮(M2、S2、K1、O1、N2、K2、P1及Q1)调和常数,对现有7个全球大洋潮汐模式的准确度进行了检验,结果显示各模式在深海大洋区域均达到了比较高的准确度:M2分潮的潮高均方根偏差在1.0～1.3cm之间;8个分潮的和方根偏差在2.1～2.3cm之间,与早期的模式相比,准确度又有了进一步提高。还依据中国近海18个岛屿的调和常数对其中的5个大洋潮汐模式的准确度进行了检验,结果表明,M2分潮均方根偏差在4.4～10cm,明显高于大洋的均方根偏差。其中日本国家天文台的潮汐模式NAO99在中国近海的结果相对较准确。     

应用数字滤波消除潮位短周期波动对确定海平面变化趋势的影响

由一元线性回归分析的正则方程计算表明,在验潮记录较短的客观条件下,验潮序列中的周期波动对确定海平面变化趋势的影响是显着的.着重讨论采用数字滤波方法消除周期小于4年的短周期波动对确定海平面变化趋势的影响,并设计了最平滤波器,其通带截止频率对应的周期为4年,即应用最平滤波器对月均验潮序列进行低通滤波,基本上可消除周期小于4年的短周期波动对确定海平面变化趋势的影响.     

基于云计算的水深测量潮位改正体系架构探索与实践

针对国外软件不能进行水深测量多站潮位改正等关键技术问题,将潮位改正理论方法与云计算技术集成,提出了潮位改正系统的体系架构。在考虑潮位控制方案、验潮站布设合理性、质量控制等水深测量技术规范要求的基础上,利用Web技术和数据库研制了具有完全自主知识产权的通用潮位改正系统。某市海岸带地质调查项目超过7 000 km测线及其所涉及的20多个验潮站的试验表明,该系统可自适应进行单站、双站、三站、多站的潮位数据改正,并可同时实施多基面的数据改正。自主开发的系统与国际Hypack软件的改正结果是一致的,满足规范要求。     

基于潮流数值模拟的设计潮位推算方法

针对一些拟建工程位于潮位不易观测地区的情况,提出了一种设计潮位的推算方法。首先,通过潮流数值计算,获得拟建工程地点一个月以上的短期潮位过程;其次,与临近的、具有长期实测资料的港口或验潮站的潮位进行同步相关分析,建立回归方程;最后,采用《海港水文规范》中的方法推算港口或验潮站的设计潮位,并将其由回归方程换算至拟建工程地点。通过算例的计算分析,表明本文方法是合理的、可行的。     

海平面上升可能使珠江三角洲灾害增加

由中国科学院、广东省科学院等 13个单位、10 0多位科技人员历时 8a合作完成的一项研究表明 ,珠江三角洲地区沿海的海平面到 2 0 30年可能会上升 30cm。研究内容包括广东海平面变化的历史背景、近期趋势和预测以及海平面上涨后的影响和对策。该项研究的数据来源于广东沿海 11个验潮站的验潮记录。根据数据 ,专家计算出相对海平面上升速率为平均每年 2至 2 5mm。据推断 ,海平面上升30cm可能会加重珠江三角洲的洪水灾害 ,使得原来按 10 0a一遇洪水设计的堤围 ,连 2 0a一遇的洪水都抵御不了。同时 ,地势低平的珠江三角洲届时将有 4 2 %的面积…     

略论全新世海面变化的波动性及其环境意义

本文根据统计分析、模型模拟、虚拟试验和多种海面变化代用资料的研究结果,提出了全新世中国东部海面和全球平均海面千年尺度波动期和两千年来中国东部海面百年尺度波动期的划分方案,分析了这些波动与同期全球和中国温度波动之间的对应关系.以长江三角洲地区为例,探讨了全新世千年-百年尺度海面波动对沿海地区海陆环境演变和人地关系的影响,提出了三角洲和沿海平原全新世海陆交互作用研究应注意从趋势模式向波动模式推进的建议.     

天津市大沽高程系统与国家高程系统数值关系

本文较为详细地介绍了天津市大沽高程系统基准地沿革。根据对天津及其周边地区的四期重复水准测量资料和大沽、青岛验潮站的验潮记录的计算和分析,求出了大沽高程系和国家黄海高程系换算公式。建议经修正后的大沽高程系可称为天津大沽高程系１９７２。并指出,这一换算关系将随时间的推移而有缓慢的变化。     

Return period estimates of extreme sea level along the east coast of India from numerical simulations

Estimates of return periods of extreme sea level events along the coast are useful for impact assessment. In this study, a vertically integrated 2D model was developed for the simulation of storm surges in the Bay of Bengal. The bathymetry for the model was derived from an improved ETOPO-5 data set, which was prepared in our earlier work. The meteorological forcing for the model was obtained from the cyclone model of Holland using the data available for 136 low-pressure systems that occurred during 1974–2000 in the Bay of Bengal. The simulated total sea level and the surge component were obtained for each event. The simulated peak levels showed good agreement with the observations available at few stations. The annual maxima of sea levels, extracted from the simulations, were fitted with Gumbel distribution using r-largest annual maxima method to estimate the 5- and 50-year return periods of extreme events at 26 stations along the east coast of India. The return periods estimated from simulated sea levels showed good agreement with those obtained from observations. The 5- and 50-year return levels of total sea level along the east coast of India show a considerable increase from south to north, with the 50-year return total sea levels being as high as 6.9 and 8.7 m at stations along the north eastern coast such as Sagar Island and Chandipur, respectively. The high return levels are expected at these stations as the cyclones developed in the Bay of Bengal generally move north or north-west, producing extreme events in the northern part, and moreover, these stations are characterized by high tidal ranges. However, at some regions in the southern part such as Surya Lanka and Machilipatnam, though 50-year return levels of total sea level are not very high (2.98 and 2.97 m, respectively) because of the relatively lower tidal ranges, high return levels of surges (0.84 and 0.57 m, respectively) are found. In addition to the role of shallow depths (5.0 and 6.1 m, respectively) at the two stations, the high return levels of surges are attributed to the effect of geometrical configuration at Surya Lanka and width (100 km) and orientation of continental shelf at Machilipatnam.     

A new Holocene sea-level curve for the southern North Sea

A new sea-level curve (MHW, mean high water level) for the southern North Sea is presented, spanning the last 10 000 years and based on new data recently obtained along the German coast. The 118 dates were selected from basal as well as intercalated peats of the Holocene sequence and archaeological dates from the last 3000 years. Because of different MHW levels along the German North Sea coast, all data were corrected to the standard tide gauge at Wilhelmshaven to make them comparable. Special advantages of this area for sea-level reconstructions are negligible tectonic and isostatic subsidence and the absence of coastal barrier systems that might have mitigated or masked sea-level changes. Changes of water level had therefore immediate consequences for the facies and could be dated exactly. The chronostratigraphic Calais-Dunkirk system has been improved and adapted to the new data. Altogether seven regressions (R 1-R 7) have been identified, each of them characterized by a distinct decline in sea level. These fluctuations are in accord with the evidence from other parts of the North Sea region. A draft of former North Sea shorelines is presented on the basis of this sea-level curve.     

广西北海现代海岸沉积作用

本文讨论了广西北海现代海岸各种环境的自然地理分带、地质营力、沉积物以及生物生态等特征，指出环境能量直接决定了环境类型、沉积物类型以及生物组合类型。海岸环境据其能量划分为高能海滩、低能海湾、中能岩质潮坪和砂质潮坪、低能泥质红树林潮坪以及高能潮上沙丘等6种沉积类型；混合沉积作用主要发育于高能海滩和中能潮坪沉积环境内。涠洲岛现代地壳的上升活动控制着该区海蚀地貌的形成。     

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Sea‐level rise has been related to global warming. The modern system on the northern coast of Anholt, Denmark, may well be analogous to other beach ridge systems formed in microtidal regimes and our results should have impact on estimation of past sea‐level variation. Ground‐penetrating radar data collected across the modern (<30 years old) berm, beach ridge and swale deposits resolve downlapping reflections interpreted to mark sea level at the time of deposition. Existing time series of sea‐level data constrain actual sea‐level variation. Nineteen readings of sea‐level markers made along our profile fluctuate within ?0.42 and 0.57 m above present mean sea level, consistent with 95% of the sea‐level data. These fluctuations reflect tidal effects and meteorological conditions. Main data uncertainties are well‐known and the sea‐level markers may be identified with a high degree of confidence.     

Insights into Holocene relative sea-level changes in the southern North Sea using an improved microfauna-based transfer function

In light of global warming and rising relative sea level (RSL), detailed reconstructions of RSL histories and their controlling processes are essential in order to manage coastal-protection challenges. This study contributes to unravelling Holocene RSL change on the East Frisian North Sea coast in high resolution and with a new approach for the German Bight. For the first time, a transfer function (vertical error: 29.7 cm ? ~11% of the mean tidal range) for RSL change based on a combined training set of benthic foraminifers and ostracods from the back-barrier tidal basin of Spiekeroog is applied to the Holocene record of the back-barrier tidal basin of Norderney. The resulting RSL curve for the Norderney tidal basin is corrected for decompaction and shows a deceleration in RSL rise between 6000 and 5000 cal bp. The smallest possible error envelope (~1 m) results from the good suitability of salt-marsh layers between 5000 and 4000 cal bp. The RSL curve provides an approach towards the closure of the common data gap of peat-based curves for the southern North Sea related to a lack of basal peats in the youngest age range, and verifies regional differences in glacial isostatic adjustment.     

Late Holocene Sea Level Reconstructions Based on Observations of Roman Fish Tanks,Tyrrhenian Coast of Italy

We present estimates for late Holocene relative sea level change along the Tyrrhenian coast of Italy based on morphological characteristics of eight submerged Roman fish tanks (piscinae) constructed between the 1st century B.C. and the 2nd century A.D. Underwater geomorphological features and archaeological remains related to past sea level have been measured and corrected using recorded tidal values. We conclude that local sea level during the Roman period did not exceed 58 ± 5 cm below the present sea level. These results broadly agree with previous observations in the region but contrast with recent analysis that suggests a significantly larger sea level rise during the last 2000 years. Using a glacial isostatic adjustment model, we explain how regional sea level change departs from the eustatic component. Our calculation of relative sea level during the Roman period provides a reference for isolating the long‐wavelength contribution to sea level change from secular sea level rise. Precise determination of sea level rise in the study area improves our understanding of secular, instrumentally observed, variations across the Mediterranean. © 2012 Wiley Periodicals, Inc.     

渤海构造收缩与沉积充填

通过对多年的渤海海岸线变化、水深变化、构造、卫星影像和水文等数据进行分析,讨论了渤海构造收缩和沉积充填问题。GPS观测结果清楚地显示渤海正处于构造收缩的过程中;地质记录以及长期验潮站的结果显示渤海海域的海平面正在下降;而地震剖面以及钻井数据则显示渤海盆地的基底沉降自上新世至今已大幅下降,和北黄海相比,目前已经停止沉降。渤海的构造收缩、海平面下降以及基底沉降的停止,这3个因素是决定渤海演化方向的3个关键因素,它们共同奠定了渤海正走向构造关闭的道路。渤海岸线的向海推进、渤海水深变浅作为强有力的地质证据呼应了渤海正在走向关闭的地质进程。黄河三角洲和辽河三角洲不断向渤海的淤积推进是在渤海必然走向关闭的地质构造背景下进行的,其淤积造陆效果非常明显,从而成为渤海快速关闭的主要因素。预计在400 a后黄河河口和辽河河口可能在渤海对接起来,至此渤海将不复存在;100 a后,莱州湾将被封闭。喜马拉雅山隆升的远程效应导致渤海的构造收缩和大量沉积物通过黄河进入渤海,从而从根本上导致渤海的关闭。从总体效果来说,渤海走向构造关闭的道路在短期内不会改变,同时也不会因为人为因素而产生明显变化。     

未来江苏中部沿海相对海面变化预测

相对海面变化是由全球绝对海面变化和区域性地面和海面因素共同控制。通过对江苏沿海近几十年来的潮位记录的分析,得出江苏沿海近期的相对海面变化速率。在此基础上根据近期绝对海面的变化速率计算出局地因素对江苏沿海相对海面变化的贡献量。在假设未来局地因素影响基本不变的前提下与IPCC对未来100年绝对海面的变化趋势 进行叠加,预测了江苏沿海未来相对海面变化的趋势。结果显示,江苏中部沿海海面在2000-2100年的100年间将上升15～152 cm,较IPCC对同期全球平均海平面上升的预测结果大的多。最后就区域性海面气压对相对海面变化的影响进行了讨论。     

Groundwater level fluctuation in the Waimea Plains, New Zealand: changes in a coastal aquifer within the last 30 years

Data for the Waimea Plains, New Zealand indicate that the lower confined groundwater aquifer is hydraulically homogeneous and that shallow groundwater levels inland are affected mostly by anthropogenic processes, while those near the coast are affected more by sea level variation. Analysis of long-term data for New Zealand indicates that sea level has increased continuously, but trends are not spatially uniform. Results from non-parametric trend analysis show that rising trends for groundwater levels are predominant in the shallow aquifer both inland on the Waimea Plains and, for recent years, near the coast, while decreasing trends are evident in the underlying confined aquifer near the coast. Groundwater level change in the shallow aquifer appears to be more affected by climate change than the lower confined aquifer. Correlation analysis indicated that groundwater levels are more affected by rainfall during the rainy season than the dry season and more influenced by rainfall inland than near the coast. Groundwater level declines in the lower confined aquifer near the coast, which has its major recharge area inland in the catchment, may be substantially affected by groundwater abstraction in inland areas as well as sea level variation, but there are little evidences of seawater intrusion. Meanwhile, groundwater recharge over the catchment area has great influence on rising groundwater levels in the shallow aquifer and its recharge is estimated to be 417.8 mm/year using chloride concentrations of precipitation and groundwater.     

A modelling approach for estimating the frequency of sea level extremes and the impact of climate change in southeast Australia

An efficient approach for evaluating storm tide return levels along the southeastern coastline of Australia under present and future climate conditions is described. Storm surge height probabilities for the present climate are estimated using hydrodynamic model simulations of surges identified in recent tide gauge records. Tides are then accounted for using a joint probability method. Storm tide height return levels obtained in this way are similar to those obtained from the direct analysis of tide gauge records. The impact of climate change on extreme sea levels is explored by adding a variety of estimates of mean sea level rise and by forcing the model with modified wind data. It is shown that climate change has the potential to reduce average recurrence intervals of present climate 1 in 100 year storm tide levels along much of the northern Bass Strait coast to between 1 and 2 years by the year 2070.