加密探空资料同化对一次降水预报能力改进研究

通过设计不同的试验方案,将加密探空资料同化到WRF模式中,对一次层状云系的降水过程进行了数值模拟.采用实时四维资料同化的方法,使得背景场和观测资料相协调,在一定程度上解决了模式的spin up问题.将温度同化到模式里,改变了模式原有的热力场,使得模式动力场随之改变,模式模拟的结果更接近实际观测.经过松弛(nudging)之后,得到的雷达回波、高度场、温度和实况很像,降水也要比不加探空资料的降水更接近实况.鉴于只有两个地方的探空资料,并不能覆盖整个模式区域,以及同化过程还需要改进,模式模拟的结果和实际观测之间还有一定的差异,有待更深入的研究.     

CSRH—Ⅱ信号传输方案的选择

分析和比较了CSRH—Ⅱ（中国频谱日像仪二期工程,即厘米波段日像仪）的几种可行光传输方案（包括全频段适时模拟光传输,分频段分时模拟光传输,数字光传输等）的技术难度及性价比。对优选的分频段分时模拟光传输作了原理性电路设计及计算。     

基于实时监测的河口糖厂滑坡监测系统研究

滑坡监测工作已经开展了多年,本文提出滑坡监测的内容包括基础因子、诱发因子和过程因子三部分,认为诱发因子和过程因子是滑坡监测的重点.针对降雨型滑坡监测,提出降雨-入渗-位移变形三者相结合的滑坡监测技术方法,并在河口糖厂滑坡监测工程中应用,实现了监测数据的实时自动采集、自动传输、自动入库的全自动监测系统.通过监测可知,河口...     

震级序列的插值新息实时预报方法

提出一种用于震级序列预报的新方法，给出其数学模型，并导出实用公式和写出用此方法编程的程序框图。对大华北地区１９００年以来的每年最大震级序列建模，给出了１９８４－１９９４年的预测结果。     

闪电位置图形处理系统

本系统与LLP公司出品的闪电位置分析仪连为一体,可以实现闪电资料实时处理、显示地闪位置和自动整理、记录闪电数据,定时或实时向用户传送闪电数据,并能以不同的地理图为背景及时反映闪电活动演变规律及移动路径,显示雷电图直观形象。也可实现闪电资料的格式化处理及向用户提供接口,为研究、统计、分析雷电资料提供了方便。新研制的系统与原系统一起组成了一个完整的雷电观测网络,扩大了其应用功能,提高了应用效益。     

数据中断对实时精密单点定位的影响分析

实时精密单点定位的应用日趋广泛,而收敛速度是其优劣的一个重要指标,在定位作业时要尽量避免多次重新收敛。利用自主研发的软件,分析了实时观测数据中断对实时精密单点定位的影响。采用基于广播星历的实时SSR改正数据的精密轨道和钟差进行实时精密单点定位。结果表明：连续60 s的数据中断会导致实时精密单点定位需要重新收敛;而频繁短时间中断但不连续中断的数据对实时精密单点定位影响不明显,不会导致重新收敛。     

The New Doppler Shift-and-Range Positioning Algorithm for the Global Navigation Satellite System

Under some circumstances in using the Global Navigation Satellite System （GNSS）, since navigation signals from the satellites are blocked a receiver cannot simultaneously track four or more satellites to estimate its 3-dimensional （3D） coordinates and clock bias. This paper proposes a Doppler Shift-and-Range （DS-R） positioning algorithm with which pseudoranges and Doppler shifts are simultaneously measured. The measurement results are used as inputs to four equations in the algorithm, and the 3D position can be estimated from the equations. Through this approach the algorithm can achieve real-time 3D positioning. By synthesizing multi-frequency observational results and adopting a new method of jointly using code-carrier phases, this algorithm expectably has accuracies similar to those of the standard approach of point positioning.     

Kalman-filter-based GPS clock estimation for near real-time positioning

In this article, an algorithm for clock offset estimation of the GPS satellites is presented. The algorithm is based on a Kalman-filter and processes undifferenced code and carrier-phase measurements of a global tracking network. The clock offset and drift of the satellite clocks are estimated along with tracking station clock offsets, tropospheric zenith path delay and carrier-phase ambiguities. The article provides a brief overview of already existing near-real-time and real-time clock products. The filter algorithm and data processing scheme is presented. Finally, the accuracy of the orbit and clock product is assessed with a precise orbit determination of the MetOp satellite and compared to results gained with other real-time products.

Real-time wave forecasting using genetic programming

The forecasting of ocean waves on real-time or online basis is necessary while carrying out any operational activity in the ocean. In order to obtain forecasts that are station-specific a time-series-based approach like stochastic modeling or artificial neural network was attempted by some investigators in the past. This paper presents an application of a relatively new soft computing tool called genetic programming for this purpose. Genetic programming is an extension of genetic algorithm and it is suited to explore dependency between input and output data sets. The wave rider buoy measurements available at two locations in the Gulf of Mexico are analyzed. The forecasts of significant wave heights are made over lead times of 3, 6, 12 and 24 h. The sample size belonged to a period of 15 years and it included an extensive testing period of 5 years. The forecasts made by the approach of genetic programming indicated that it can be regarded as a promising tool for future applications to ocean predictions.     

BDS/GPS动态RTK技术在超高层变形监测中的应用

随着我国北斗导航系统的发展,多系统组合在变形监测中的应用将是今后发展的趋势。为了监测超高层的变形趋势,本文利用BDS/GPS组合RTK技术对国内某超高层进行变形监测,经分析发现,BDS/GPS组合相比于单系统卫星可见数目增多,PDOP值减小,卫星空间分布得到改善,变形监测精度以及稳定性相比于单系统有了很大提高,能更精确的监测出超高层的变形趋势。