中国新疆博斯腾湖全新世沉积环境年代学特征

通过对博斯腾湖沉积物湖芯样品进行137Cs,14C-AMS测年分析,湖芯剖面上有明显的1986年的切尔诺贝利核事故蓄积峰,以及1975年和1963年次蓄积峰,这些137Cs蓄积峰对博斯腾湖现代沉积有明显的时标意义。通过质量深度与年代分析,博斯腾湖的沉积速率相对稳定,平均沉积速率为0.13±0.01g/cm2.a。与14C年代获得的中全新世以来的平均沉积速率0.13±0.03cm/a和0.12±0.05cm/a相似,表明博斯腾湖中全新世以来的沉积环境较稳定,并且也说明14C-AMS测年分析所得的结果较为可靠,可以利用博斯腾湖沉积物样品测定的14C年代进行线性回归作年代校正,由于湖泊沉积物中老碳效应的影响,博斯腾湖沉积物有机质14C测年偏老约650a左右。     

应用GMS5多通道云图估计降水技术的研究

对近两年来5～8月中国东部地区120多个测站雨量观测资料和对应4400多幅GMS-5四个通道云图的研究发现：红外亮温的时间、空间变率、红外和水汽通道亮温差等云图衍生资料对消除卷云，弥补夜间缺少可见光云图的不足起到明显作用。从而，应用双判据双重MOS多元回归法建立四通道云图因子、衍生因子与降水量之间的回归方程，进行6小时分级降水估计。为了进一步消除厚卷云和特殊地形的影响，提出使用逐日实时资料自动建立多元回归方程估计降水量，从而对双判据双重MOS多元回归法估计结果进行校正。上海中心气象台的业务使用表明，总体估计的准确率达70％左右。     

国家气象中心客观要素预报--MOS系统

面向全国2000多个台站，应用数值预报产品释用MOS技术制作温度、降水、相对湿度、风、云量及能见度等要素预报，并实现了预报业务运行。通过建立MOS预报系统，表明预报因子和预报对象的处理、建方程前的参数选择以及预报因子的选取都会影响要素预报的质量，需要做大量的细致工作。预报检验结果显示，降水预报尚未达到可用程度．温度和相对湿度的短期预报在大多数情况下是可用的或是可参考的，但还有待进一步改进。降水预报尚需在预报因子和充分运用多种探测信息方面加以改进。     

夏季降水量与气温资料的恢复试验

该文对我国汛期降水量和气温缺测资料及资料均一性恢复的方法进行试验研究。对单个气候地区（东北区），以及全国6个气候地区用逐步回归和逐步判别方法进行缺测1～5年恢复试验。对东北地区内所有站点的试验表明，逐步判别分析方法比逐步回归分析方法恢复效果好些；选择邻站用判别分析方法建立的恢复模型，效果更好。全国气候地区试验表明，选择邻站的判别分析方法有较好的恢复效果。     

鄱阳湖区平垸行洪、退田还湖后的防洪减灾形势分析

根据鄱阳湖区“退田还湖”的实际资料，采用洪水模拟的方法分析计算出“退田还湖”降低湖口站洪水位和减少1954年洪水超额分洪量，分析了“退田还湖”后鄱阳湖区的防洪减灾形势，提出应继续加强对鄱阳湖区防洪工程的建设，探讨了“退田还湖”后江湖洪水关系的变化趋势。     

泰斯模型的统计分析求解

本文利用统计分析来求解水文地质参数,原理简单,解是唯一的。其基本思想是利用非稳定流抽水试验获得的s-t系列资料,以泰斯公式为参考模型,建立试验系列的非线性统计模型,求解导水系数T和贮水系数μ 。统计模型既可利用目前先进的软件辅助求解,亦可利用一台可编程计算器完成计算。本文借助一个实例,应用MATLAB语言的统计分析工具的多元回归分析模块进行求解,获得了理想的结果。     

RIVER SYSTEM AND DISTURBANCE FACTORS IN THE LAKE TOBA

Situated at an elevation of 905 m above sea level in the Province of North Sumatra, Lake Toba and its surrounding landscapes are regarded as a natural heritage in a certain extent, as a quoted national treasure. Unfortunately degradation of the land and water resources in the watershed along Lake Toba is taking place at an alarming and totally unacceptable rate. The quality of the lake is partly depended on input the quality of the rivers. When compared to the control area the water quality that influenced by the piggeries are highly polluted. It can be concluded that the Salbe River at the downstream of the piggeries has been polluted and apparently it is a serious problem to the catchment area management. It should be noted that the polluted river would influence the water quality of the Lake Toba. Based on calculation, the permissible BOD5 according to B- river standard is 238 mg/L, it means the river still in B standard but the condition and quality are decreasing continuously. Following the Indonesian health standard the permissible BOD is - 461 mg/L. It means BOD in the river should be reduced 461 mg/L or clean program is needed.     

Geomorphic and sedimentological signature of a two‐phase outburst flood from moraine‐dammed Queen Bess Lake,British Columbia,Canada

On 12 August 1997, the lower part of Diadem Glacier in the southern Coast Mountains of British Columbia fell into Queen Bess Lake and produced a train of large waves. The waves overtopped the broad end moraine at the east end of the lake and ?ooded the valley of the west fork of Nostetuko River. The displacement waves also incised the out?ow channel across the moraine. Stratigraphic and sedimentologic evidence supports the conclusion that the ?ood had two phases, one related to wave overtopping and a second to breach formation. Empirical equations were used to calculate the peak discharge of the ?ood at various points along the west fork of the Nostetuko valley and to describe the attenuation of the ?ood wave. The velocity of the ?ood was also calculated to determine the time it took for the ?ood to reach the main fork of Nostetuko River. The highest peak discharges were achieved in the upper reach of the valley during the displacement phase of the ?ood. Peak discharge declined rapidly just below the moraine dam, with little change thereafter for approximately 7 km. Empirical formulae and boulder measurements indicate a rise in peak discharge in the lower part of the west fork valley. We suggest that ?ow in the upper part of the valley records the passage of two separate ?ood peaks and that the rise in discharge in the lower part of the valley is due to amalgamation of the wave and breach peaks. Hydraulic ponding in con?ned reaches of the valley extended the duration of the ?ood. In addition, erosion of vegetation and sediment in the channel and valley sides may also have exerted an in?uence on the duration and nature of ?ooding. Sediments were deposited both upstream and downstream of channel constrictions and on a large fan extending out into the trunk Nostetuko River valley. This study extends our understanding of the variety and complexity of outburst ?oods from naturally dammed lakes. It also shows that simple empirical and other models for estimating peak discharges of outburst ?oods are likely to yield erroneous results. Copyright © 2005 John Wiley & Sons, Ltd.     

Study on comparison between absolute and relative input energy spectra and effects of ductility factor

Introduction Estimation of an attenuation relationship for strong ground motion parameters has been an interesting research subject in the field of engineering seismology and has played a very important role in seismic safety evaluation, seismic zoning, seismic hazard evaluation of major constructions, etc. At present, the generally used parameters include peak acceleration, peak velocity and elastic response spectrum. Such parameters mentioned above are essentially independent of the duration…     

Channel geometry of mountain streams in New Zealand

A dataset of 21 study reaches in the Porter and Kowai rivers (eastern side of the South Island), and 13 study reaches in Camp Creek and adjacent catchments (western side of the South Island) was used to examine downstream hydraulic geometry of mountain streams in New Zealand. Streams in the eastern and western regions both exhibit well-developed downstream hydraulic geometry, as indicated by strong correlations between channel top width, bankfull depth, mean velocity, and bankfull discharge. Exponents for the hydraulic geometry relations are similar to average values for rivers worldwide. Factors such as colluvial sediment input to the channels, colluvial processes along the channels, tectonic uplift, and discontinuous bedrock exposure along the channels might be expected to complicate adjustment of channel geometry to downstream increases in discharge. The presence of well-developed downstream hydraulic geometry relations despite these complicating factors is interpreted to indicate that the ratio of hydraulic driving forces to substrate resisting forces is sufficiently large to permit channel adjustment to relatively frequent discharges.