走航ADCP数据处理与质量控制方法研究

介绍了声学多普勒流速剖面仪(ADCP)测流的基本原理和利用ADCP自带软件进行原始数据处理过程中需要设置的关键参数;着重论述了ADCP数据标准化处理和质量控制方法的研究,并利用实测数据对研究方法进行了验证。结果表明,本文研究的方法针对ADCP底跟踪观测数据处理效果良好,并可为GPS跟踪模式下的ADCP数据处理和质量控制提供可行的技术参考。     

Estimating uncertainty of streamflow measurements with moving-boat acoustic Doppler current profilers

A theoretical and a semi-empirical model are presented for estimating the uncertainty of streamflow measurements made with an acoustic Doppler current profiler (ADCP) mounted on a moving platform. Both models are based on the statistical analysis of ADCP ensemble discharge time series collected during a transect; therefore, they account for all random error sources associated with the measurement at a site. The theoretical model is developed based on the law of propagation of variance; it explores the theoretical relationship between the variables involved in the problem. The semi-empirical model is developed based on the theory of dimensional analysis; it explores the empirical relationship between the variables. The semi-empirical model is calibrated using 205 transect datasets and verified with an additional 382 transect datasets. It provides a useful tool for the uncertainty analysis and uncertainty-based measurement quality control of moving-boat ADCP streamflow measurements.     

台湾东北黑潮入侵东海陆架强度的变化规律:持续一年的ADCP现场流速观测

本文利用台湾东北陆坡附近海域持续一年的多普勒流速剖面仪(AcousticDopplerCurrent Profilers,ADCP)定点深水测流数据提取了观测站点处黑潮跨陆坡入侵强度的时间序列,并与美国海军混合坐标海洋模式(HybridCoordinateOceanModel,HYCOM)分析数据中提取的观测站点处以及台湾东北陆坡东西区段黑潮入侵强度的时间序列进行了对比研究。研究结果显示黑潮在观测站点处的跨陆坡入侵强度存在显著的季节和季节内变化特征,并且与台湾东北黑潮主轴位置的摆动有较好的对应关系,黑潮主轴东(西)移,则黑潮在台湾东北陆坡西段及观测站点处的入侵显著减弱(增强),而在台湾东北陆坡东段的入侵显著增强(减弱)。此外,观测站点处黑潮跨陆坡入侵强度的时间序列还显示出较强的10d和20d左右的短周期信号,其中10d的周期信号对应着东海黑潮斜压不稳定波动的特征周期,而20d的周期信号则体现了台湾东北附近海域局地涡旋的短期变化。     

基于海上实测的秋刀鱼舷提网沉降和提升性能研究

根据2015年7-10月和2016年6-10月蓬莱京鲁渔业有限公司"鲁蓬远渔019"在西北太平洋进行的海上秋刀鱼舷提网网具性能测试所获得的数据,采用线性回归方法,分析了舷提网在沉降和提升阶段,网衣的沉降深度和提升深度以及网具沉降速度和提升速度的变化状况。利用广义加性模型(GAM)探讨秋刀鱼舷提网沉降深度和提升速度各自有效的影响因子,且分析了这些影响因子与舷提网主要性能参数两者之间的关系。结果发现:(1)网衣沉降深度随时间连续增加;网具下纲和侧纲的沉降速度都是先逐渐增大,然后缓慢减小,直至沉降过程结束;网衣沉降速度波动剧烈,无规律性变化。(2)网具下纲、侧纲的提升速度均快速达到最大值然后随时间连续降低,下纲的最大提升速度大于侧纲,网衣提升速度无规律性变化,上下波动剧烈。(3)GAM模型结果显示,30 m水层流速、60 m水层流速、下纲纲索松放长度3个因子对网衣最大沉降深度有显著性影响(P0.05),影响程度依次为30 m水层的流速下纲纲索松放长度60 m水层流速。30 m水层流速和绞网速度两个因子对平均提升速度有着显著性影响(P0.05),其中,绞网速度影响最大。     

截流水文泥沙监测中几个关键技术的研究与实践

基于三峡工程大江截流水文泥沙监测除常规水文要素外,要求监测围堰龙口和导流明渠附近水体多维水文要素的时间和空间动态变化,因此应尽可能应用相关科技的最新成果和一切先进经验,成熟的技术方法和设备。本文介绍了其中无人立尺接测水位ＡＤＣＰ测流,龙口测验,ＧＰＳ和数据传输等几个关键部位,关键技术室内外研究实验及现场率定校正的情况,实践证明,这些技术的研究与应用,为截流水文泥沙监测打下了基础,并发挥了重要作用。     

2008年8—9月份吕宋海峡西南侧锚定ADCP的斜压海流观测

2008年8月份在吕宋海峡西侧大约4000m深的海域首次布放了两套深水潜标,对上层海洋进行了为期一个月的高频率ADCP海流采样。对数据进行了多重处理,分解得到平均流和逐层潮流,并分析了具有斜压性海流的频率分布。调和分析结果表明,该海域以不规则日周期潮流为主,潮流椭圆随深度旋转。海流的功率谱分析表明,内潮能量在温跃层附近最大,并随深度减小,同时海流有明显的近惯性振荡信号。该观测为了解吕宋海峡深层海洋的潮流、近惯性运动以及海峡水交换提供了第一手的资料。     

Circulation on the West Antarctic Peninsula derived from 6 years of shipboard ADCP transects

Over the past 30 years, shelf circulation on the West Antarctic Peninsula (WAP) has been derived from hydrographic data with a reasonable level of confidence. However, with the exception of a very few drifter tracks and current-meter timeseries from moorings, direct velocity measurements have not previously been available. In this article, shelf and shelf-edge circulation is examined using a new velocity dataset, consisting of several years of acoustic Doppler current profiler transects, routinely collected along the ship tracks of the R/V Gould and the R/V Palmer since the fall of 1997. Initial processing and quality control is performed by Dr. Teresa Chereskin and Dr. Eric Firing, who then place the data in an archive accessible by public website, resulting in the broad availability of the data for a variety of uses. In this study, gridded Eulerian means have been calculated to examine circulation on the shelf and slope off the South Shetland Islands, in Bransfield Strait, and on the shelf and slope south of these regions, including Marguerite Bay and the adjacent shelf and shelf-edge. Shelf-edge flow is northeastward in the study area from the offshore of northern Alexander Island to Smith Island, while a southward flowing shelf-edge feature, probably the shallow component of the polar slope current, appears between Elephant Island and Livingston Island. The shallow polar slope current appears to turn shoreward to pass through Boyd Strait between Smith and Livingston Islands. In Bransfield Strait, there is cyclonic circulation. The previously identified northeastward-flowing South Shetland Island jet is strong and present in all seasons, with a large barotropic component not revealed by the hydrography-based velocities derived in the past. On the shelf seaward of Adelaide, Anvers and Brabant Islands, the strong along-shelf Antarctic Peninsula coastal current flows southwestward, with strongest velocities in winter (June–September) off Anvers and Brabant Islands, but stronger in summer (December–March) off Adelaide Island. Seaward of Marguerite Bay, there is seaward flow in the upper 400 m of the water column over the southwest bank of Marguerite Trough, strongest in summer, and shoreward flow near the northeast bank and adjacent shallower shelf areas.     

Study of the Kuroshio/Ryukyu Current system based on satellite-altimeter and <Emphasis Type="Italic">in situ</Emphasis> measurements

Data from satellite altimeters and from a 13-month deployment of in situ instruments are used to determine an empirical relationship between sea-level anomaly difference (SLA) across the Kuroshio in the East China Sea (ECS-Kuroshio) and net transport near 28°N. Applying this relationship to the altimeter data, we obtain a 12-year time series of ECS-Kuroshio transport crossing the C-line (KT). The resulting mean transport is 18.7 ± 0.2 Sv with 1.8 Sv standard deviation. This KT is compared with a similarly-determined time series of net Ryukyu Current transport crossing the O-line near 26°N southeast of Okinawa (RT). Their mean sum (24 Sv) is less than the mean predicted Sverdrup transport. These KT and RT mean-flow estimates form a consistent pattern with historical estimates of other mean flows in the East China Sea/Philippine Basin region. While mean KT is larger than mean RT by a factor of 3.5, the amplitude of the KT annual cycle is only half that of RT. At the 95% confidence level the transports are coherent at periods of about 2 years and 100–200 days, with RT leading KT by about 60 days in each case. At the annual period, the transports are coherent at the 90% confidence level with KT leading RT by 4–5 months. While the bulk of the Kuroshio enters the ECS through the channel between Taiwan and Yonaguni-jima, analysis of satellite altimetry maps, together with the transport time series, indicates that the effect of mesoscale eddies is transmitted to the ECS via the Kerama Gap southwest of Okinawa. Once the effect of these eddies is felt by the ECS-Kuroshio at 28°N, it is advected rapidly to the Tokara Strait.     

DGPS走航测深验潮技术中的潮位信息提取方法

提出了一种提取观测海域潮位信息的新方法--DGPS走航测深验潮技术,即在走航ADCP重复测量断面潮周期流场观测的同时获取潮位信息,并实现水下地形的潮位改正.该方法通过重复测量点瞬时水深数据选取、潮位差数据计算、叠加拟合和迭代逼近等预处理与算法,可在潮差约1.6 m、地形起伏高达10～20 m的台湾浅滩沙波区,获取均方根误差小于0.1 m的潮位观测结果.     

Two‐dimensional and three‐dimensional computational models in hydrodynamic and morphodynamic reconstructions of a river bend: sensitivity and functionality

This study assesses hydrodynamic and morphodynamic model sensitivity and functionality in a curved channel. The sensitivity of a depth‐averaged model to user‐defined parameters (grain size, roughness, transverse bed slope effect, transport relations and secondary flow) is tested. According to the sensitivity analysis, grain size, transverse bed slope effect and sediment transport relations are critical to simulated meander bend morphodynamics. The parametrization of grain size has the most remarkable effect: field‐based grain size parametrization is necessary in a successful morphodynamic reconstruction of a meander bend. The roughness parametrization method affects the distribution of flow velocities and therefore also morphodynamics. The combined effect of various parameters needs further research. Two‐dimensional (2D) and three‐dimensional (3D) reconstructions of a natural meander bend during a flood event are assessed against field measurements of acoustic Doppler current profiler and multi‐temporal mobile laser scanning data. The depth‐averaged velocities are simulated satisfactorily (differences from acoustic Doppler current profiler velocities 5–14%) in both 2D and 3D simulations, but the advantage of the 3D hydrodynamic model is unquestionable because of its ability to model vertical and near‐bed flows. The measured and modelled near‐bed flow, however, differed notably from each other's, the reason of which was left open for future research. It was challenging to model flow direction beyond the apex. The 3D flow features, which also affected the distribution of the bed shear stress, seem not to have much effect on the predicted morphodynamics: the 2D and 3D morphodynamic reconstructions over the point bar resembled each other closely. Although common features between the modelled and measured morphological changes were also found, some specific changes that occurred were not evident in the simulation results. Our results show that short‐term, sub‐bend scale morphodynamic processes of a natural meander bend are challenging to model, which implies that they are affected by factors that have been neglected in the simulations. The modelling of short‐term morphodynamics in natural curved channel is a challenge that requires further study. Copyright © 2014 John Wiley & Sons, Ltd.