国外区域发展规划的全新审视及对中国的借鉴*

从100年来国外区域发展规划总体演变历程入手,提出了国家“高度指令+强制干预”体制下、“统一领导+总体协调”体制下和“不统不控+政策当先”体制下区域发展规划的三大生成模式,认为国家政治经济体制的变革主宰着规划的命运,作为特定时期政府一项重要职能的规划的局限性在所难免。中国在区域发展规划中必须重视计划与市场的适度结合,公众参与与政治参与的有机协调,建立健全规划中的立法管理体系,并注重对生态环境和可持续发展问题的研究。     

数据差分格网化在CORS系统中的研究

为了解决网络实时动态测量数据处理软件对并发用户数的限制,提出了采用数据差分格网化方法,研究了数据差分网格化方法在连续运行参考站系统中的应用,对差分格网化方法进行事后处理和实测结果对比分析,对比测试结果。测试结果表明,数据差分格网化方法满足了广大用户对厘米级定位的需求。     

我国IGS站的周期变化特征

利用谱方法和小波技术分析了我国IGS站坐标时间序列,阐述了其周期变化特征,即绝大部分台站在N、E、U方向都具有半年周期性、年周期性,U方向周期特性相对明显,同时台站的主要周期成分和时频局部特性又具有一定区域性.     

复杂地质条件下顶拱大型不稳定块体分析与预测

锦屏一级水电站2#尾水调压室所处位置地质条件复杂,在桩号0+320~0+360和0+0~0+120之间开挖时局部掉块严重。本文综合分析后,提出了2#尾调室顶拱未开挖域产生大型不稳定块体的必要条件是:(1)由节理①④F183组结构面和开挖临空面切割产生;(2)块体大小主要取决于节理组①和④的延伸长度;(3)较大不稳定块体的产生区域,必然位于F18断层带下盘。对2#尾调室顶拱进行搜索预测,预测结果表明该潜在块体位于未开挖区域桩号0+180～0+260之间,规模约为50m3,重达133.5t。根据块体理论分析,其稳定性系数为1.052,处于临界状态,应采取相应的应急支护补强措施。     

CORS在线定位用户服务系统

首先对基于CORS的在线定位用户服务系统功能进行了较细致的分析,将其概括为7项基本功能和4项扩展功能。在此基础上提出了系统架构方案,将系统划分为3个部件和20个子部件,并对各组成部分的功能作了较详细的阐述。最后,针对用户数据上传与存储、基线解算和基线向量网平差等核心功能,提出了较具体的设计方案,并对软件实现与系统集成方法进行了阐述。     

白鹤滩水电站冬春季两次极端强风天气的对比分析

利用FNL 1°×1°再分析资料和常规气象观测资料从时空上统计分析了白鹤滩水电站大风天气过程,选取2个冬春季11级极端强风个例进行对比分析,从环流形势、天气系统、地形作用、物理量场、斜温图等方面揭示了大风形成、发展的原因。结果表明:白鹤滩水电站受大风天气影响巨大,特别是冬春季,且存在明显季节差异;电站地形复杂,狭管效应显著,冷空气南下、山谷风活动、河谷狭管效应及下垫面摩擦力共同作用,导致了大风天气的发生。"2.21"过程与"3.10"过程大尺度环流形势基本一致,但冷空气位置、强度及影响时间不同,散度涡度场、水汽通量散度场及垂直速度场的分布对大风天气有较好的指示作用,强风区对应垂直螺旋度上负下正的垂直结构;还总结了斜温图中大风天气的预报指标,为预报大风天气提供了经验。     

Preserving Continuity of Long-Term Daily Maximum and Minimum Temperature Observations with Automation of Reference Climate Stations using Overlapping Data and Meteorological Conditions

The seasonal-by-wind bias method for aligning time series of daily maximum and minimum temperatures from past conventional staffed and new automated sites using closely collocated, overlapping observations is presented for twenty-two modernized Reference Climate Stations in Canada. The method consists of adjusting for incompatible observing times and deriving biases from the daily “manual-minus-automated” temperature differences classified into seasons and wind-speed conditions. Most of the biases vary with the season, and many show limited wind dependency. Four sets of adjusted time series are prepared based on two-year and five-year overlapping data and on seasonal bias with or without wind conditions; the adjusted data are compared with the original observations. Based on the mean of the absolute differences and examination of box plots, the results show that, for this particular set of stations, the two-year versus five-year and seasonal versus seasonal-by-wind bias adjusted time series are overall similar. The largest contribution to the improvements in the adjusted observations came from matching the times of observation. Additionally, daily temperatures are adjusted using statistical methods applied with neighbouring station data but no overlapping observations at collocated stations; it is concluded that these do not necessarily resolve the bias between staffed and automated sites.     

水电开发对大渡河瀑布沟以下河段的水温影响

为探究水电开发对大渡河水温过程的影响,采用原型观测和数学模型相结合的方法,对比分析了瀑布沟电站开发前后下游河道的水温时空变化特性。研究成果表明,与天然情况相比,现阶段瀑布沟下游沿程水温出现了明显的均化效应和延迟效应以及春夏季低温水、秋冬季高温水现象,最大降温2.4℃出现在4月的龚嘴尾水断面,最大升温3.3℃出现在12月的瀑布沟尾水断面;瀑布沟下游小型水库均未出现水温分层现象,但形成的蓄水体对沿程升温有一定的弱化,沿程增温率由天然状态的0.8℃/100 km降至现阶段的0.5℃/100 km;采用考虑了机械能转化的数学模型能较好地模拟瀑布沟下游河道的水温过程,率定得到的"机械能-内能"转化率为55%。     

梯级水电开发对大通河流域洪水过程的影响分析

应用大通河流域实测洪水资料和水利普查数据,定性和定量分析了梯级水电开发对流域洪水过程和洪水特征的影响,建立了梯级水电站数量与洪水涨落率、涨落频次的数学关系模型。结果表明:随着流域水电站数量的增多,洪水过程变化频繁,洪水涨落率增大,涨落频次增多;梯级水电开发使流域最大洪峰流量增大了19.7%~21.5%,最大洪峰传播时间减少了6.1%,而对次洪水总量的影响较小。研究水文过程受人类活动的影响规律,对加强流域水电站统一调度、水能水资源可持续利用和水生态文明建设具有十分重要的意义。     

Observed fluxes of water,salt and suspended sediment in a partly mixed estuary

Observations of the residual fluxes of water, salt and suspended sediment are presented for seven stations along the Tamar Estuary. The data include measurements over single spring and neap tidal cycles, and are generally applicable to medium or high run-off conditions.Surface to bed differences in salinity are typically of the order of several parts per thousand. Gravitational circulation is an important component of residual flow in the deep, lower reaches of the estuary. Here, Stokes drift is insignificant. In the shallow upper reaches, the major residual currents are generated by Stokes drift and freshwater inputs. Data are compared with predictions from Hansen and Rattray's (1966) model of estuarine circulation.Salt fluxes due to tidal pumping and vertical shear are directed up-estuary at spring tides, tidal pumping being dominant. Tidal pumping of salt is also directed up-estuary at neap tides, although it is insignificant in the lower reaches, where vertical shear dominates.Tidal pumping of suspended sediment is directed up-estuary near the head at spring tides, and probably contributes to the formation of the turbidity maximum. The existence of the turbidity maximum is predicted using a simplified model of the transport of water and sediment. The model shows that an additional mechanism for the existence of the turbidity maximum is an up-estuary maximum in the tidal current speeds (and thus resuspension). In the lower reaches, transport of suspended sediment is directed down-estuary at both spring and neap tides, and sediment is essentially flushed to sea with the fresh water.