大型综合交通枢纽流线组织设计

大型综合交通枢纽在实现各种功能的同时,如何打造便捷舒适的交通流线组织,实现车流、人流的快捷疏散,是规划设计中需要高度重视的问题。结合深圳北站综合交通枢纽工程的总体规划设计,对人流和车流组织进行优化设计,提出人流组织的基本要点和措施,阐述“人车分流”、“无缝接驳”的设计理念,突显流线组织在综合枢纽设计中的核心地位,并最终实现乘客在5 min内无缝换乘各种交通工具的设计目标。     

渗井在华北平原区合理降低路基高度设计中的应用

针对华北平原区路基高度普遍偏高以及河北省大广高速公路深州至大名段的地质特点,提出渗井在高速公路下穿式被交道路中的设计思路．并结合具体应用分析其带来的经济效益,对于实现公路建设的可持续发展和“环境友好”、“资源节约”的环保型公路建设的目的,具有积极的促进作用。     

我国煤炭“铁海联运”现状分析

我国煤炭资源丰富,但分布极不平衡,主要集中在北方地区。华东、华南地区是我国经济活跃和发达地区,工业发展快,电力需求量大,而煤炭资源缺乏,对煤炭需求量大且稳定。介绍区域性的严重不平衡所形成的我国“北煤南运”、“西煤东运”、“铁海联运”的基本格局,分析“铁海联运”的发展趋势,可为我国煤炭运输通道建设提供参考。     

Optimal interpolation of sea surface temperature for the North Sea and Baltic Sea

Sea surface temperature fields of the North Sea and Baltic Sea have been constructed for the year 2001 using a multiplatform Optimal Interpolation scheme. The analyzed fields are constructed every 12 h on a 10 km spatial grid. The product is based upon observations from the three NOAA satellites 12, 14 and 16 together with a large amount of in situ observations. Space dependent covariance functions are estimated from the satellite observations and account for spatial and temporal lags. Several independent methods have been used to assess the error on the sea surface temperature product. Compared against independent in situ observations, the mean RMS difference for the year 2001 is 0.78 °C. The spatial distribution of the errors reveals that the Baltic Sea in general show higher errors than the North Sea. The error statistics throughout the year show a temporal variation of the errors with maximum during summer and winter. Tests with a varying number of satellite observations show that the accuracy of the satellite observations is the most important parameter in terms of reducing the errors on the interpolated sea surface temperature product.     

西北太平洋温带气旋中波浪的分布特征

利用日本发布的2006—2009年的亚洲地面分析图和西北太平洋波浪分析图,对冬春季发生在西北太平洋上的156个温带气旋的波浪分布特征进行了统计分析,得到了温带气旋中最大波高和4 m以上大浪的一般分布特征:最大波高中心主要分布在气旋中心S-SW方向上100~600 n mile范围内,其中200~300 n mile范围内出现率最高;4 m以上大浪范围不以气旋中心呈对称分布,气旋南侧大于北侧,其中西南侧最大;最大波高和4 m以上大浪范围与气旋强度有关,一般强度越强,最大波高和4 m以上大浪范围越大,反之,则越小。对于中心气压在980 hPa以下的强温带气旋,最大波高均在6 m以上,平均最大波高在8 m以上,4 m以上大浪的平均最大范围可达1 000 n mile以上,平均最小范围在300 n mile以上。     

5U北美岩沥青改性沥青路用性能试验研究

5U北美岩沥青是一种天然沥青改性剂,为评价其路用性能,采用流变学方法对5U北美岩沥青改性沥青胶浆性能进行了动态温度扫描,对改性后沥青混合料的高温性能与抗水损坏性能进行了室内评价。研究结果表明:经5U北美岩沥青改性后的沥青胶浆车辙因子明显提高,弹性增加;沥青混合料抗车辙能力和抗水损害能力明显改善。     

Convection and the seeding of the North Atlantic bloom

Observations of vertical velocities in deep wintertime mixed layers using neutrally buoyant floats show that the convectively driven vertical velocities, roughly 1000 m per day, greatly exceed the sinking velocities of phytoplankton, 10 m or less per day. These velocities mix plankton effectively and uniformly across the convective layer and are therefore capable of returning those that have sunk to depth back into the euphotic zone. This mechanism cycles cells through the surface layer during the winter and provides a seed population for the spring bloom. A simple model of this mechanism applied to immortal phytoplankton in the subpolar Labrador Sea predicts that the seed population in early spring will be a few percent of the fall concentration if the plankton sink more slowly than the mean rate at which the surface well-mixed layer grows over the winter. Plankton that sink faster than this will mostly sink into the abyss with only a minute fraction remaining by spring. The shallower mixed layers of mid-latitudes are predicted to be much less effective at maintaining a seed population over the winter, limiting the ability of rapidly sinking cells to survive the winter.     

Validation of a hybrid optimal interpolation and Kalman filter scheme for sea surface temperature assimilation

A hybrid data assimilation scheme designed for operational assimilation of satellite sea surface temperatures (SST) into an ocean model has been developed and validated against in-situ observations. The scheme consists of an optimal interpolation (OI) part and a greatly simplified Kalman filter (KF) part.The OI is performed only in the longitudinal and latitudinal directions. A climatological field is used as a background field for the interpolation. It is constructed by fitting daily averages of satellite SST to the annual mean, annual, and semiannual harmonics in a 20 km by 20 km grid. The background error covariance is approximated by a spatially varying two-dimensional exponential covariance model. The parameters of the covariance model are fitted to the deviations of the satellite data from the background field using data from a full year.The simplified KF uses ocean model forecasts as a background field. It is based on the assumption that it is possible to neglect horizontal SST covariances in the filter and that the typical time scale for vertical mixing in the mixed layer is much shorter than the average time between observations. We therefore assume that the error variance in a column of water is evenly spread out throughout the mixed layer. The result of these simplifications is a computationally very efficient KF.A one year validation of the scheme is performed for year 2001 using an operational eddy resolving ocean model covering the North Sea and the Baltic Sea. It is found that assimilation of sea surface temperature data reduces the model root mean square error from 1.13 °C to 0.70 °C. The hybrid scheme is found to reduce the root mean square error slightly more than the simplified KF without OI to 0.66 °C. The inclusion of spatially varying satellite error variances does not improve the performance of the scheme significantly.     

论上海北外滩航运服务功能的拓展

上海国际航运中心的发展和黄浦江的开发为北外滩航运服务功能的拓展提供了契机。本文分析了北外滩航运服务功能历史发展概况和现状 ,阐述了北外滩航运服务功能开发的机遇和挑战、优势和劣势 ,最后提出了北外滩航运服务功能发展的要求和建议。