2003年淮河流域特大暴雨期间低纬环流分析

利用NCEP NCAR提供的OLR和气象要素场再分析资料 ,对 2 0 0 3年 6～ 7月淮河流域特大暴雨期间西南季风和东亚季风以及热带低纬地区环流的异常特征及其对梅雨暴雨的贡献进行了分析。结果表明 ,暴雨期间 ,长江流域附近地区维持准稳定的比常年明显偏强的南风带 ,北方冷空气亦比常年偏强 ;三次强降雨过程 ,低层均表现为稳定的强南风与阶段性增强的偏北气流的经向辐合。三次强降水过程中有两次 ,来自西北太平洋的东南气流的水汽输送占主导地位。异常环流分析表明 ,淮河流域强降雨时段 ,东南亚季风和南海季风异常偏弱 ;赤道西北太平洋地区东风气流比常年同期异常偏强。诊断分析认为 ,高原东部和南部地区对流活动比常年同期偏弱 ,80～1 1 5°E地区越赤道气流比常年异常偏弱 ,可能是西南季风异常偏弱原因。而偏强的WAKER环流可能是西北太平洋地区低纬地区东风异常偏强的原因。另外 ,印度尼西亚地区低层气流辐合异常偏强有利于副高的稳定和加强 ,进而使我国东南部地区长时间维持强异常偏强的东南气流 ,从而为淮河流域的持续暴雨提供了源源不断的来自南海和西北太平洋的暖湿气流     

甘肃省测绘地理信息成果分发服务系统的设计与实现

根据现代社会各行业对测绘地理信息档案成果的需求,档案信息化已成为档案存储、管理、应用的趋势和要求。本文基于档案信息化项目背景,阐述和分析了测绘地理信息成果分发服务系统的实现与集成等关键技术。     

Study on the Configuration of Towed Flexible Cables

Based on the fundamental equation of flexible cable dynamics for a towed system, an easily solved mathematical model is set up in this paper by means of appropriate simplification. Several regular patterns of spatial motion of towed flexible cables in water are obtained through numerical simulation with the finite difference method, and then modification and verification by trial results at sea. A technical support is provided for the towing ship to maneuver properly when a flexible cable is towed. Furthermore, the relations between two towed flexible cables, which are towed simultaneously by a ship, are investigated. The results show that the ship towing two flexible cables is safe under the suggested arrangement of two winches for the towing system, and the coiling/uncoiling sequences of the cables as well as the suggested way of maneuvering.     

胶州湾的初级生产力和新生产力

海洋初级生产力是海洋食物链的基础,是进行海洋生物资源评估和合理开发利用的基本依据。70年代在国际生物圈计刘(IBP)的推动下,本领域的一些学者曾在世界各大洋的代表性海区进行过大量现场观测研究。最近,随着世界性的资源与环境问題的日趋严重,全球C循环已成为人们关注的研究课题。海洋初级生产力是了解全球C循环必不可少的指标之一,因而再度成为生物海洋学家的研究对象。新生产力是总初级生产力的一部分,亦是海洋N循环的特征参数,对于大洋水域而言,它反映了真光层生物群落的净生产力,代表了真光层向下输出的C通量,是当今有关国际研究计划,如全球海洋通量联合研究( JGOFS)的核心内容之一。初级生产力和新生产力的研究,对于海洋生物资源的持续利用和C、N生物地球化学循环具有十分重要的意义。 胶州湾作为我国温带地区的典型海湾,已成为我国生态研究系统网络(CERN)的野外观测站。代表性的地理位置和强度开发下的生态条件,使其生态学资料在环境监测和资源开发方面极具理论意义和应用价值。胶州湾的初级生产力曾用黑白瓶生氧量法测定过(郭玉洁等,1992),而新生产力的实测研究在国内尚属空白。本文运用14C,15N同位素示踪方法,在胶州湾进行了季节性的初级生产力和新生产力现场实验研究,获得了比较系统的观测资料。     

Analysis and Research of Ice Loads Acting on Offshore Structures

- Usually, the action of sea ice on offshore engineering structures is one of the controlling loads in cold waters engineering structure design. The reasonable selection of environmental condition and the physical mechanical properties of ice in the region are directly related to the structure design, operation and safety. In this paper, the sea ice force acting on the structure, the physical mechanical properties of ice and the selection of parameters in calculation are discussed. Some suggestions are proposed as to the calculation of various kinds of ice loads acting on the structure.     

Comparison of Linear Level I Green-Naghdi Theory with Linear Wave Theory for Prediction of Hydroelastic Responses of VLFS

Very Large Floating Structures (VLFS) have drawn considerable attention recently due to their potential significance in the exploitation of ocean resources and in the utilization of ocean space. Efficient and accurate estimation of their hydroelastic responses to waves is very important for the design. Recently, an efficient numerical algorithm was developed by Ertekin and Kim (1999). However, in their analysis, the linear Level I Green-Naghdi (GN) theory is employed to describe fluid dynamics instead of the conventional linear wave (LW) theory of finite water depth. They claimed that this linear level I GN theory provided betler predictions of the hydroelastic responses of VLFS than the linear wave theory. In this paper, a detailed derivation is given in the conventional linear wave theory framework with the same quantity as used in the linear level I GN theory framework. This allows a critical comparison between the linear wave theory and the linear level I GN theory. it is found that the linear level     

应用模糊识别方法进行水库鱼产力等级评判

将模糊识别方法用于水库鱼产力等级评判,为解决定量评价由于多指标交迭而造成的难判、误判提供新途径。对山东省部分代表性大、中型水库的应用表明,效果是令人满意的。     

On the Interaction of Surface Waves with An Elastic Plate of Finite Length in Head Seas

An eigen-function expansion method based on a new orthogonal inner product is proposed by Sahoo et al. (2000) for the study of the hydroelastic response of mat-type VLFS in head seas. However, their main emphasis is on the effect of edge conditions and they assume that the plate is of a semi-infinite length. In reality, the plate is of finile length. For consider-alion of the finite length effect, the reflection and transmission from the other end must be considered. The effect of this reflection and transmission on the hydroelaslic response of VLFS is of interest for praclical application. Furthermore, the physi-cal meaning of the new inner producl was not given in their paper. In this paper, it is shown that the new inner product can be derived from the governing equation and the bottom boundary conditions. Then the same eigen-function expansion method is adopted for the study of the hydroelastic response of an elastic plate of finite length in surface waves. Delailed comparisons are made between the     

影响水库鱼产力的基础环境因素的分析

本文以山东省30座代表性的大中型水库为样本,对影响水库鱼产力的基础环影境条件——集雨区性状、水库形态和水文状况各方面共计21项变量,运用聚类分析、主成分分析、相关分析和逐步回归等方法进行了分析和筛选。结果表明,影响水库鱼产力的主要因素是:集雨区的土壤、相对人口密度、植被覆盖率以及水文换率等。其中,最重要的是土壤肥力,文中建立的土壤肥力指数(SF1),第一次定量证明了集雨区、土壤对水库营养水平乃至鱼产力的决定性作用。这些关键性影响因素可作为评价水库鱼产力的环境指标。     

基于FIA和光学原理的酶传感器检测海水甲基对硫磷

将乙酰胆碱酯酶(acetylcholinesterase,AChE)传感器与流动注射系统(flow injection analysis system,FIA)相结合,通过光学方法测定固定化酶受农药抑制后的残余活性,对海水中微量甲基对硫磷进行定量分析。该系统的适宜工作条件为:温度30℃;固定化酶的用量0.05 U;载液流速0.45 mL/min;进样时间20 min;底物(碘化硫代乙酰胆碱)溶液浓度0.100 mol/L,注射量100μL。在0.1~100μg/L之间,农药浓度的对数值与固定化酶活性的抑制率之间具有良好的线性关系(r=0.995 3)。利用该系统检测含甲基对硫磷分别为0.8μg/L和5.0μg/L的模拟海水样品,获得了较好的准确度和精密度,平均相对误差和变异系数均小于10%。