南海北部次表层盐度的变化及其与北赤道流分叉点的关系

吕宋海峡是南海与外界水交换的重要通道,黑潮作为北太平洋最强的1支西边界流,在经过吕宋海峡时会对南海北部的环流和环境产生重要影响。本文用1991—2011年期间CTD断面实测资料和高度计资料,提取23.0~25.5 kg/m³等密度面之间的盐度极大值,研究了南海北部不同年月盐度极大值变化、黑潮入侵方式与强弱,以及盐度极大值变化与北赤道流分叉点南北移动的关系,结果表明:(1)黑潮入侵南海方式多样,既有分支形式,也有弯曲、流套形式。(2)不同年月间,黑潮入侵南海的强弱存在较大差别,120°E断面的次表层盐度极大值的变动可超过0.3。(3)北赤道流分叉点位置的南北变动对黑潮入侵南海的强弱具有重要影响:北赤道流分叉点位置偏北,黑潮入侵南海较强;北赤道流分叉点位置偏南,则黑潮入侵相对较弱。     

汶川地震崩塌滚石坡面运动特征

滚石坡面运动影响因素众多,分析预测困难,确定崩塌滚石危害范围,对崩塌灾害防治具有重要意义。在实测汶川地震399条崩塌滚石剖面基础上,通过统计分析研究了滚石运动特征和危害范围参数,得出如下结论：(1) 滚石坡面运动可划分为启动阶段、运动阶段和堆积阶段;56º为启动区滚石自由坠落模式和滑动、滚动模式界限,堆积区最大角度为39.6º,26º以下区域为减速带。(2) 滚石运动距离与高度的比值,随着地震烈度以及边坡岩石强度的增高而增大,并给出了统计公式。(3) 滚石最大运动距离与坡高之间以及陡坡段坡度与滚石运动扩散角之间有较好的线性关系,根据堆积区在边坡高度上所占比例,划分了两种坡面形态,给出了两种坡面形态边坡陡坡段坡度与滚石运动扩散角之间的统计关系图,可作为崩塌滚石危害范围判定的参考。     

Trend,periodicity and abrupt change in streamflow of the East River,the Pearl River basin

The East River in the Pearl River basin, China, plays a vital role in the water supply for mega‐cities within and in the vicinity of the Pearl River Delta. Knowledge of statistical variability of streamflow is therefore important for water resources management in the basin. This study analyzed streamflow from four hydrological stations on the East River for a period of 1951–2009, using ensemble empirical mode decomposition (EEMD), continuous wavelet transform (CWT) technique, scanning t and F tests. Results indicated increasing/decreasing streamflow in the East River basin before/after the 1980s. After the early 1970s, the high/low flow components were decreasing/increasing. CWT‐based analysis demonstrates a significant impact of water reservoirs on the periodicity of streamflow. Scanning t and F test indicates that significantly abrupt changes in streamflow are largely influenced by both water reservoirs construction and precipitation changes. Thus, changes of streamflow, which are reflected by variations of trend, periodicity and abrupt change, are due to both water reservoir construction and precipitation changes. Further, the changes of volume of streamflow in the East River are in good agreement with precipitation changes. Copyright © 2012 John Wiley & Sons, Ltd.     

室外风对高层建筑外保温层火灾发展的影响研究

近年来,由外墙保温材料引起的高层建筑火灾频繁发生,使得高层建筑室外火灾已经成为当下防火安全工程研究的热点议题。高层建筑外墙火灾受室外风影响较大,本研究采用CFD（Computational Fluid Dynamics）火灾模拟软件FDS,针对当前典型高层住宅建筑进行室外风作用下外保温材料火灾特性的模拟研究,分析了不同风向风速作用下外墙保温材料的火灾燃烧性能,研究了室外风对火灾烟气温度、运动速度、CO体积分数、可见度、火灾热释放速率等参数的影响。研究结果表明：室外风对火灾热释放速率等火灾作用参数有着较大影响,并存在一定的规律性。研究成果对未来高层节能建筑的防火设计施工具有一定的借鉴意义。     

Could ocean currents be responsible for the west to east spread of aquatic invasive species in Maritime Canadian waters?

The circulation in the shelf seas of Maritime Canada is predominantly in the northeast–southwest direction. Despite the mean northeast–southwest flow, a number of AIS invasions have been observed to proceed in the opposite direction – from the Gulf of Maine, around Nova Scotia, and into the southern Gulf of St. Lawrence. Flow fields from a numerical circulation model are used to investigate whether these invasions could be due to drift in ocean currents. Particle tracking experiments are performed and probability density functions (PDFs) derived that describe the probability of drifting a given upstream distance in a given drift time. Analysis of these PDFs revealed that for invasions that took 20–40 y to occur, propagule drift in ocean currents could be responsible for the upstream spread, while this was not the case for short timescale invasions (<10 y). Rafting could be responsible for both short and long timescale invasions.     

Boundary layer dissipation and the nonlinear interaction of equatorial baroclinic and barotropic rossby waves

Two-layer equatorial primitive equations for the free troposphere in the presence of a thin atmospheric boundary layer and thermal dissipation are developed here. An asymptotic theory for the resonant nonlinear interaction of long equatorial baroclinic and barotropic Rossby waves is derived in the presence of such dissipation. In this model, a self-consistent asymptotic derivation establishes that boundary layer flows are generated by meridional pressure gradients in the lower troposphere and give rise to degenerate equatorial Ekman friction. That is to say, the asymptotic model has the property that the dissipation matrix has one eigenvalue which is nearly zero: therefore the dynamics rapidly dissipates flows with pressure at the base of the troposphere and creates barotropic/baroclinic spin up/spin down. The simplified asymptotic equations for the amplitudes of the dissipative equatorial barotropic and baroclinic waves are studied by linear theory and integrated numerically. The results indicate that although the dissipation slightly weakens the tropics to midlatitude connection, strong localized wave packets are nonetheless able to exchange energy between barotropic and baroclinic waves on intraseasonal timescales in the presence of baroclinic mean shear. Interesting dissipation balanced wave-mean flow states are discovered through numerical simulations. In general, the boundary layer dissipation is very efficient for flows in which the barotropic and baroclinic components are of the same sign at the base of the free troposphere whereas the boundary layer dissipation is less efficient for flows whose barotropic and baroclinic components are of opposite sign at the base of the free troposphere.     

平顶山矿区岩溶水系统水-岩相互作用的随机水文地球化学模拟

在前期工作的基础上,基于新的（补充）采集的地下水化学样品的分析数据,以ＷＡＴＥＱ４Ｆ模型为基础,应用本次研究中开发的耦合的ＭｏｎｔｅＣａｒｌｏ－ＷＡＴＥＱ４Ｆ模型,对平顶山矿区地下水系统中水－岩反应状态进行了随机水文地球化学模拟和评价。结果表明：随机水文地球化学模拟方法具有很好的实用性和应用性和应用前景;在模拟研究区内地下水相对于方解石、、白云石、威武央过饱和,而与玉髓处于平衡状态。这些结果为该区     

298.15K下LiCl-Li_2B_4O_7-H_2O体系中LiCl的活度系数和离解平衡研究

用锂离子选择电极和经典 Ag- Ag Cl电极测定了 2 98.15K下 L i Cl- Li2 B4 O7- H2 O体系中离子强度范围为 0 .0 1～ 2 .50 mol· kg-1,不同 Li2 B4 O7离子强度分数的 L i Cl的平均活度系数。由实验数据 ,用迭代法及多元线性回归法 ,求取了 L i2 B4 O7的化学计量离解平衡常数 Km,热力学离解平衡常数 K及 Pitzer离子作用参数 ,并与实验值比较标准偏差为 0 .0 50 0。同时该实验结果在 0 .0 1- 0 .50 mol·kg-1离子强度范围内与 2 98.15K下 L i Cl- L i2 SO4 - H2 O体系 L i Cl平均活度系数的变化趋势进行了比较 ,得到 L i Cl在 Li2 B4 O7介质中平均活度系数随 Yb的增大而增大 ,而在 L i2 SO4 介质中则减小     

沙冬青抗旱机理的探讨

通过对沙冬青抗旱机理的探讨,经数理统计分析,初步认为沙冬青具有很低的水势和蒸腾强度,而束缚水含量很高,说明沙冬青原生质细胞具抗旱特点。叶片具有厚的角质层,浓密的表皮毛,气孔下陷,叶肉全部为栅栏组织,具抗旱结构。沙冬青不但具有较发达的根系,水势低,吸水能力很强,而且从叶到茎都具有抑制蒸腾失水的旱生结构。可见沙冬青是以尽可能多地吸收水分并减少蒸腾失水的方式来调节体内水分平衡,以适应干旱的严酷环境