The Combined Effect of Initial Error and Model Error on ENSO Prediction Uncertainty Generated by the Zebiak-Cane Model

Initial errors and model errors are the source of prediction errors. In this study, the authors compute the conditional nonlinear optimal perturbation （CNOP）-type initial errors and nonlinear forcing singular vector （NFSV）- type tendency errors of the Zebiak-Cane model with respect to El Nifio events and analyze their combined effect on the prediction errors for E1 Nino events. The CNOP- type initial error （NFSV-type tendency error） represents the initial errors （model errors） that have the largest effect on prediction uncertainties for E1 Nifio events under the perfect model （perfect initial conditions） scenario. How- ever, when the CNOP-type initial errors and the NFSV- type tendency errors are simultaneously considered in the model, the prediction errors caused by them are not am- plified as the authors expected. Specifically, the predic- tion errors caused by the combined mode of CNOP-type initial errors and NFSV-type tendency errors are a little larger than those caused by the NFSV-type tendency er- rors. This fact emphasizes a need to investigate the opti- mal combined mode of initial errors and tendency errors that cause the largest prediction error for E1 Nifio events.     

斜压罗斯贝变形半径优化的误差相关尺度及其对最优插值效果的改进

利用最优插值方法进行三维温盐场重构时,如何正确估算背景场误差协方差至关重要。针对背景场误差协方差主要取决于误差相关尺度的问题,本文提出了用中国东部海域及其附近海域的最新的高分辨率气候态数据进行斜压罗斯贝变形半径优化其误差相关尺度计算的研究方案和技术途径;对比分析了均一化相关尺度方案和法国ISAS系统尺度方案,讨论了变形半径对最优插值的影响。结果表明:均一化相关尺度方案的均方根误差小于ISAS方案,但温度场过于平滑,难以刻画一些重要的物理现象;相比而言,本文提出的基于变形半径的相关尺度方案在取2倍变形半径时,不仅均方根误差在各水平层较小,且温度场能够更好地刻画四国海盆海域涡旋及黑潮影响的温度场三维结构。由于实际海洋中各层物理过程的尺度存在差异,实际应用时各层的最优尺度设置也应有所不同。     

基于阈值区间的海洋锋面提取模型

A model （Bayesian oceanic front detection, BOFD） of sea surface temperature （SST） front detection in satel- lite-derived SST images based on a threshold interval is presented, to be used in different applications such as climatic and environmental studies or fisheries. The model first computes the SST gradient by using a Sobel algorithm template. On the basis of the gradient value, the threshold interval is determined by a gradi- ent cumulative histogram. According to this threshold interval, front candidates can be acquired and prior probability and likelihood can be calculated. Whether or not the candidates are front points can be deter- mined by using the Bayesian decision theory. The model is evaluated on the Advanced Very High-Resolution Radiometer images of part of the Kuroshio front region. Results are compared with those obtained by using several SST front detection methods proposed in the literature. This comparison shows that the BOFD not only suppresses noise and small-scale fronts, but also retains continuous fronts.     

应用极化合成孔径雷达检测海上溢油研究进展

海上溢油给海洋生态环境带来严重的影响,快速准确地探测溢油对于防灾减灾具有重要的意义。利用卫星遥感探测溢油已成为目前主要的检测手段,大多采用合成孔径雷达(SAR)数据,运用图像处理的方法,开展了多种溢油提取算法的研究,取得了较好的结果,但由于海洋的类溢油现象存在,造成提取信息的精度达不到要求。近年来,国内外运用极化SAR数据开展溢油信息提取研究,从极化分解与相位差等角度对溢油特性分析,能有效地区分一些类溢油现象,得到了较理想的结果。分析了应用SAR数据开展溢油信息提取的研究状况,总结了溢油极化SAR探测的研究,指出了目前研究中存在的不足,并提出了今后溢油极化SAR遥感监测的方向。     

基于GPS反射信号技术的渤海海冰实验

传统的海冰检测手段都存在着受天气影响或实时检测成本太高的缺点,为了更实时有效的检测海冰,减轻海冰灾害对于我国的影响,并达到防灾减灾的目的,本文研究了GPS反射信号(GPS-R)技术检测海冰的可能性。通过对2013年2月下旬在中国天津渤海湾的岸基架设GPS信号接收机所接收的观测数据进行分析,使用不同特性的反射海域(几乎全为海水或是海冰)的数据进行比对分析,其结果显示极化比值(反射左旋信号与直射右旋信号的比值)能够明显反演海冰密集度。本文首次将GPS-R技术应用于国内自主设计的渤海海冰检测实验中。     

海杂波微弱目标分形检测

The target on the sea surface is complex and difficult to detect due to the interference of backscattered returns from the sea surface illuminated by the radar pulse. Detrended fluctuation analysis （DFA） has been used successfully to extract the time-domain Hurst exponent of sea-clutter series. Since the frequency of the sea clutter mainly concentrates around Doppler center so that we consider to extract frequency-do- main fractal characterization and then detect a weak target within sea clutter by using the difference of frequency-domain fractal characterization. The generalized detrended fluctuation analysis （GDFA） is more flexible than traditional DFA owing to its smoothing action for the clutters. In this paper, we apply the GDFA to evaluate the generalized Hurst exponent of sea-clutter series in the frequency domain. The difference of generalized Hurst exponents between different sea-clutter range bins would be used to determine whether the target exists. Moreover, some simulations with the real IPIX radar data have also been demonstrated in order to suooort this conclusion.     

海洋能发电装备现场检测技术研究

近年来,随着海洋能发电装备研发工作的不断深入,其性能测试工作越来越受到人们的重视。因此,在综合分析目前我国海洋能发电装备研发现状以及海洋能发电装备测试需求的基础上,提出了海洋能发电装备现场检测平台设计方案。主要介绍了现场检测平台的基本功能和系统构成。该方案使得设计出的现场检测平台能够满足波浪能、潮流能等海洋能发电装备功率特性和电能质量特性的测试需求。被测海洋能发电装备可以是已进入实海况示范试验阶段的全比例尺或小比例尺工程样机。     

从Nio-3指数看MJO不确定性对ENSO可预报性的影响

通过在Zebiak Cane数值模式中引入参数化MJO随机外强迫,着重从Nio 3指数的演变发展探讨了MJO不确定性对ENSO可预报性的影响。结果表明,对Zebiak Cane模式而言,MJO不确定性对由条件非线性最优扰动(CNOP)导致的ENSO事件最大预报误差影响较小;与初始误差相比,由MJO不确定性产生的模式误差在ENSO预报不确定性的产生中具有较小作用,对ENSO可预报性的影响不显著。该结果强调了初始误差在ENSO预报不确定性中的主要作用,从而为ENSO预测的资料同化提供了理论基础。     

多模式智能路灯控制系统

使用AT89S52单片机作为主控芯片,设计了一种多模式智能路灯控制系统,该系统能够根据道路、巷口或定时应用3种情况进行工作模式选择,并根据环境光亮度决定是否启动所设定的工作模式.巷口工作模式时,系统通过红外传感器检测道路上有汽车或行人通过时,将识别信号送入单片机,由单片机控制交通灯开启;道路工作模式时,路灯处于开启状态,以保障行人畅行;定时模式时,通过DS1302定时模块,可以设定路灯的开关时间.此外,该系统还具有自动故障检测功能,功能全面,有较强的实用价值.     

更正

正本刊2014年第3期第101页《关于垂准仪一测回垂准测量标准偏差检测方法的探讨》一文第二章第3节中,二维点坐标标准偏差计算公式应为