Tectonics of the Scandian orogeny and the Western Gneiss Region in southern Norway

Two crust-forming events dominate the Precambrian history of the Western Gneiss Region (WGR) at about 1800–1600 Ma and 1550–1400 Ma. The influence of the Sveconorwegian orogeny (1200–900 Ma) is restricted to the region south of Moldefjord-Romsdalen. A series of anorthosites and related intrusives are present, possibly derived from the now-lost western margin of the Baltic craton that may have been emplaced in the WGR as an allochthonous unit before the Ordovician.The Caledonian development is split into two orogenic phases, the Finnmarkian (Cambrian — Early Ordovician) and the Scandian (Late Ordovician/Early Silurian — Devonian). The lower tectonic units west of the Trondheim Trough may be Finnmarkian nappes ; they were part of the lower plate during the Scandian continental collision. The Blåhö nappe is correlated with dismembered eclogite bodies along the coast. A regional change of nappe transport direction from 090 to 135 marks the initiation of an orogen-parallel sinistral shear component around 425 Ma. The change caused the development of a complex sinistral strike-slip system in the Trondheim region consisting of the Möre-Tröndelag Fault Zone and the Gränse contact. The latter cut the crust underneath the already emplaced Trondheim Nappe Complex, thus triggering the intrusion of the Fongen-Hyllingen igneous complex, and initiating subsidence of the Trondheim Trough, and was subsequently turned from a strike-slip zone into an extensional fault. Minor southward transport of the Trondheim Nappe Complex rejuvenated some thrusts between the Lower and the Middle Allochthon. A seismic reflector underneath the WGR is interpreted to be a blind thrust which subcrops into the Faltungsgraben. During Middle Devonian orogenic collapse, detachment faulting brought higher units, now eroded elsewhere, down to the present outcrop level, such as the Bergen and Dalsfjord nappe and the Old Red basins.     

多层递推平稳模型

通过对小概率事件历史样本作多层递推迭代，逐次改变引入样本数求取权函数，建立一种平稳统计模式。模式信息容量大，收敛快，克服了常规统计模式的局限性，在灾害性天气客观预报模型应用中取得了明显效果。     

大坝变形监测数据回归分析中的因子选择

本文对我国大坝变形资料分析中常用的逐步回归分析进行了探讨,指出这种方法通常所选的因子数偏少,其原因来自自变量之间的复共线性的影响。为了克服复共线性对因子筛选的影响,文中对因子筛选提出了若干有益的建议。     

近代回归分析在交通调查分析建模中的应用

本文以出行发生量模型的建立为例,较为系统地讨论了近代回归分析中的自变量选择及回归诊断方法在交通调查分析建模中的应用。分析了在获取调查数据后,如何借助回归自变量选择方法来选择最佳自变量子集,以确定简捷的回归模型;文中应用回归诊断方法,讨论了修正回归模型、探测错误的调查数据的方法,从而为建立简捷、高精度的交通模型打下了基础。最后,作者提出了应用自变量选择及回归诊断方法建立出行发行量模型的一般步骤。     

Assessment of episodic acidification in Sierra Nevada,California

Monte-Carlo simulations were used to assess the extent of shortterm alkalinity depressions occuring in Sierra Nevada lakes due to acidic deposition events. The Episodic Event Model (EEM) was used to simulate spring snowmelt events. Snow course data, precipitation data and lake acidification surveys were used to derive values for the EEM parameters. Spring snowmelt events were shown to have great impacts on the water quality of Sierran lakes. Lakes are likely to be most affected by the early-spring snowmelt event because the epilimnion depth is at a minimum, which indicates minimum dilution. Under annual average loading conditions, no Sierran lake has been reported as acidic although 29% of the lakes have alkalinities less than 40 µeq/L indicating a sensitivity to acidification. In simulations of early-spring snowmelt events, using present-day acidic loading conditions, it was estimated 79% ± 9% of the lakes would experience shortterm lake alkalinity depressions to levels less than 40 µeq/L. The results provided by the model simulations are valuable in establishing upper and lower limits on the extent of possible episodic acidification to lake-resources-at-risk. The most critical parameters controlling the magnitude of lake alkalinity depressions during snowmelt episodic events are a) the lake area to watershed area ratio — a measure of input loading, and b) the epilimnion volume — a measure of dilution and mixing.     

通量传输事件磁场的理论计算及其与观测的比较

根据涡旋诱发重联理论,对通量传输事件（FTEs）磁场分布特性作了计算.结果表明,卫星测到的FTEs的不同磁场分布形态,是取决于通量管的运动方向及卫星穿越通量管的部位.在北半球,当通量管由低纬向高纬（由南向北）直向运动时,不论卫星通过什么部位,绝大多数情况下观测到先正后负的B_x,变化（即正FTE）,个别部位观测到先负后正的B_x变化（即反FTE）;B_z是单峰分布形式,表现为V型、倒V型或是U型和倒U型.当通量管在x方向有正或负速度分量即斜向运动时,大部分部位测到的B_x呈不规则变化,B_z表现为双极分布.与61个FTEs的观测实例作了对比,理论计算与观测符合得较好.     

Earthquakes in the Czech Republic and Surrounding Regions in 1995–1999

In the time span from January 1995 to December 1999 the Czech National Seismological Network (CNSN), consisting of ten permanent digital broadband stations, several local networks and two data centers, detected and recorded 9530 regional natural seismic events, 27 greater than magnitude 2. Most of these events were located by the Czech Seismological Service (CSS), and the most prominent of them were analyzed in detail. A large number of quarry blasts were recorded as well but were not included in the analysis. We provide basic information on the configuration of the CNSN and on the way of routine data processing employed by the CSS in this paper. The over-all regional seismicity monitored by the CNSN in 1995–1999 is briefly reviewed. The main results of observations and evaluation of the local (NW-Bohemia/Vogtland, South Bohemia, Sudeten) and induced (Kladno, Píbram, Upper Silesia, Lubin/Poland) seismic activity within this period are presented in a condensed form. Finally, a summary on macroseismic observations on the territory of the Czech Republic in 1995–1999 is also presented.     

末次冰期东亚季风快速波动的模式与成因

通过对位于东亚季风区中东部与西部边缘的两个高分辨率黄土剖面记录的对比研究，发现它们不仅捕捉到了20个Dansgaard Oeschger事件与6个Heinrich事件，而且黄土记录与GRIP冰芯记录的这些快速气候波动基本上是同步的。暗示在整个末次冰期，东亚季风气候同样存在千年—百年尺度上的快速波动。所不同的是，西面的沙沟剖面对这些快速气候波动的反应比东面的王官剖面敏感。结合末次冰期中国黄土记录的先前研究结果，我们发现，自西向东Dansgaard Oeschger旋回的幅度逐渐变小，推测这主要是由西风与东亚夏季风共同作用所造成的。     

An Experiment Using the High Resolution Eta and WRF Models to Forecast Heavy Precipitation over India

In the present study using the Weather Research and Forecasting (WRF) and Eta models, recent heavy rainfall events that occurred (i) over parts of Maharastra during 26 to 27 July, 2005, (ii) over coastal Tamilnadu and south coastal Andhra Pradesh during 24 to 28 October, 2005, and (iii) the tropical cyclone of 30 September to 3 October, 2004/Monsoon Depression of 2 to 5 October 2004, that developed during the withdrawal phase of the southwest monsoon season of 2004 have been investigated. Also sensitivity experiments have been conducted with the WRF model to test the impact of microphysical and cumulus parameterization schemes in capturing the extreme weather events. The results show that the WRF model with the microphysical process and cumulus parameterization schemes of Ferrier et al. and Betts-Miller-Janjic was able to capture the heavy rainfall events better than the other schemes. It is also observed that the WRF model was able to predict mesoscale rainfall more realistically in comparison to the Eta model of the same resolution.