Diagnosis of physical and biological controls on phytoplankton distribution in the Sargasso Sea

The linkage between physical and biological processes is studied by applying a one-dimensional physical-biological coupled model to the Sargasso Sea. The physical model is the Princeton Ocean Model and the biological model is a five-component system including phytoplankton, zooplankton, nitrate, ammonium, and detritus. The coupling between the physical and biological model is accomplished through vertical mixing which is parameterized by the level 2.5 Mellor and Yamada turbulence closure scheme. The coupled model investigates the annual cycle of ecosystem production and the response to external forcing, such as heat flux, wind stress, and surface salinity, and the relative importance of physical processes in affecting the ecosystem. Sensitivity experiments are also carried out, which provide information on how the model bio-chemical parameters affect the biological system. The computed seasonal cycles compare reasonably well with the observations of the Bermuda Atlantic Time-series Study (BATS). The spring bloom of phytoplankton occurs in March and April, right after the weakening of the winter mixing and before the establishment of the summer stratification. The bloom of zooplankton occurs about two weeks after the bloom of phytoplankton. The sensitivity experiments show that zooplankton is more sensitive to the variations of biochemical parameters than phytoplankton.     

基于流强度的中国城市对外服务能力时空演变特征

综合运用城市流强度模型、改良Theil系数和K-means时空聚类法对2004~2010年中国地级以上286个城市对外服务能力的时空演变特征进行探讨,得到以下结论:1城市流强度值的绝对量均有明显上升,但存在显著的区域非均衡现象,并与城市经济实力有较高的相关性。2省内差异对城市对外服务能力的差异贡献率在58%~72%,是其空间尺度差异的主要来源。3时空演变表现出明显的阶段性和等级性规律,且空间等级性特征随阶段演进更趋明显。4对外服务能力的强弱和集聚强化趋势与城市流强度基数值大小和增速快慢有着紧密关系,一定程度上体现了基础乘数效应和循环累积效应配置下的非均衡特征。     

一种基于点对应的激光扫描仪外方位参数检校方法

本文设计了一种检校标志用以激光扫描仪的检校,利用三平面相交得到检校标志中的特征点在激光扫描仪坐标系和全站仪坐标系中的坐标值,根据点点对应采用平差的方法计算得到两坐标系之间的变换矩阵,最后给出实验结果和精度分析.     

玉林电视台塔楼雷击的分析与防护改造

经过对玉林电视台塔楼遭受强雷击损害,避雷针保护与针（网）混合保护比对,引下线根数对分流系数影响,变压器设置在建筑物内外对雷击风险值影响的分析,得出电视台塔楼应采取针（网）混合保护、增加防雷引下线根数和变压器设置在建筑物内部等防护改造措施。     

Impact of external factors on sperm motility of Sepiella maindroni

Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evaluate the influence of external factors, including temperature, salinity, pH, glucose, NaCl, KCl, MgCl2, CaCl2, EDTA-2Na and artificial seawater on sperm motility. The results show that the appropriate activation and motility condition for sperm were: temperature 20?30°C (optimum 25°C), salinity 10.6?30.6 (optimum 15.9) and pH 8.0?8.6 (optimum 8.0-8.4). Sperm activity varied in different concentrations of glucose, NaCl, KCl, MgCl2 and CaCl2. None of the selected concentrations of EDTA-2Na solution could activate the sperm. The activation rate in artificial seawater devoid of Ca2+, Mg2+ or HCO3ˉ was low. The results should help further studies on the preservation and activation of squid sperm.     

Variation of surface temperature during the last millennium in a simulation with the FGOALS-gl climate system model

A reasonable past millennial climate simulation relies heavily on the specified external forcings, including both natural and anthropogenic forcing agents. In this paper, we examine the surface temperature responses to specified external forcing agents in a millennium-scale transient climate simulation with the fast version of LASG IAP Flexible Global Ocean-Atmosphere-Land System model (FGOALS-gl) developed in the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics (LASG/IAP). The model presents a reasonable performance in comparison with reconstructions of surface temperature. Differentiated from significant changes in the 20th century at the global scale, changes during the natural-forcing-dominant period are mainly manifested in the Northern Hemisphere. Seasonally, modeled significant changes are more pronounced during the wintertime at higher latitudes. This may be a manifestation of polar amplification associated with sea-ice-temperature positive feedback. The climate responses to total external forcings can explain about half of the climate variance during the whole millennium period, especially at decadal timescales. Surface temperature in the Antarctic shows heterogeneous and insignificant changes during the preindustrial period and the climate response to external forcings is undetectable due to the strong internal variability. The model response to specified external forcings is modulated by cloud radiative forcing (CRF). The CRF acts against the fluctuations of external forcings. Effects of clouds are manifested in shortwave radiation by changes in cloud water during the natural-forcing-dominant period, but mainly in longwave radiation by a decrease in cloud amount in the anthropogenic-forcing-dominant period.     

2003年以来长春市城市功能用地演替

城市空间的增长不仅仅表现在城市用地的扩张,还表现在城市功能用地的演替。城市功能用地的演替可以更加深刻地揭示城市空间外延式水平扩展的内在特征,是城市功能集聚与扩散的空间反映。以长春市中心城区为例,利用2003、2007、2010、2012年4个年份的遥感影像图、地形图及城市用地现状图等数据资源,借助Arc GIS、Auto CAD等软件,运用GIS分析方法,在分析中心城区城市空间扩展的总体格局及城市用地结构变化的基础上,提出以外部扩展与内部更替来表达城市功能用地的演替,进而阐释城市空间扩展及城市功能集聚与扩散的内在特征,为城市空间扩展的研究提供一种新的、有效的手段,以丰富城市空间研究的理论成果体系。     

Incorporating elevation in rainfall interpolation in Tunisia using geostatistical methods

Abstract

This paper compares the performance of three geostatistical algorithms, which integrate elevation as an auxiliary variable: kriging with external drift (KED); kriging combined with regression, called regression kriging (RK) or kriging after detrending; and co-kriging (CK). These three methods differ by the way by in which the secondary information is introduced into the prediction procedure. They are applied to improve the prediction of the monthly average rainfall observations measured at 106 climatic stations in Tunisia over an area of 164 150 km² using the elevation as the auxiliary variable. The experimental sample semivariograms, residual semivariograms and cross-variograms are constructed and fitted to estimate the rainfall levels and the estimation variance at the nodes of a square grid of 20 km?×?20 km resolution and to develop corresponding contour maps. Contour diagrams for KED and RK were similar and exhibited a pattern corresponding more closely to local topographic features when (a) the network is sparse and (b) the rainfall–elevation correlation is poor, while CK showed a smooth zonal pattern. Smaller prediction variances are obtained for the RK algorithm. The cross-validation showed that the RMSE obtained for CK gave better results than for KED or RK.

Editor D. Koutsoyiannis; Associate editor C. Onof

Citation Feki, H., Slimani, M., and Cudennec, C., 2012. Incorporating elevation in rainfall interpolation in Tunisia using geostatistical methods. Hydrological Sciences Journal, 57 (7), 1294–1314.     

含腐蚀缺陷高强钢厚壁管道压溃压力预测方法

腐蚀是管道常见的缺陷形式之一,会极大降低管道的压溃压力,同时深海环境下高静水外压易引发管道压溃失效,威胁管道的安全运行,因此准确预测管道压溃压力显得尤为重要。采用数值模拟方法研究了含腐蚀缺陷的高强钢厚壁管道压溃失效模式,分析了管材、管道径厚比、腐蚀深度、长度和宽度等参数对高强钢厚壁管道压溃压力的影响规律。分析结果表明:管道径厚比愈大,对厚壁管道的承压能力提升愈显著;腐蚀缺陷的存在对管道压溃压力具有减小作用;随着管道材料等级的提升,压溃压力有明显提高。提出了相应的压溃压力预测公式,为厚壁管道完整性评价提供了参考依据。     

日本钢筋混凝土结构抗震加固技术现状与发展趋势

既有钢筋混凝土结构的丰富而可靠的抗震加固技术是提升我国建筑物抗震性能,实现社会可持续发展的重要保障.在长期工程实践的积累中,日本建筑界逐渐发展出一套行之有效的抗震性能评估、加固设计体系和多种多样的抗震加固技术,值得我国借鉴.文章在简要回顾日本抗震加固设计方法之后,介绍了日本钢筋混凝土结构抗震加固的传统方法,总结了近年来在传统加固方法基础上所做的改良,并在此基础上,从外附子结构、消能减震化和自复位技术等3个方面归纳了日本新一代钢筋混凝土结构抗震加固技术的发展趋势.