A study on the flux,speciation, and budget of mercury in controlled experimental ecosystems

The lowest addition of mercury (0.1 ug Hg 1⁻¹) was used in CEEs for research on mercury flux, speciation and budget. The removal behavior of mercury by phytoplankton in water columns of CEEs can be described by first order kinetic equations for total and particulate mercury in the CEE spiked by mercury. The removal rate of mercury in water columns depends on the size and productivity of phytoplanton in a water column to which mercuric ions were added. A 4.4 day half-life time and a 2.8 day half-life time for total and particulate mercury respectively was obtained in diatom bloom. During microflagellate bloom a 30 day total mercury half-life time was estimated with increase of particulate mercury in the water column. The 0.010 ug Hg cm⁻²y⁻¹ mercury flux rate that was attained in the control bag agreed with the values from field measurements in Saanich Inlet where the bags were launched. The proportion of total mercury to dissolved and particulate mercury depended also on the size, productivity, and concentration of mercury in a water column. A more or less constant distribution of mercury species in the control bag was observed as follows: dissolved Hg 0.73, particulate Hg 0.27, inorganic Hg 0.42, dissolved organic Hg 0.31. After spiking with mercury, the particulate mercury rose rapidly and reached to over 70% of the total mercury. The concentration factor of mercury by phytoplankton in the CEEs in the order of 10⁵ was consistent with the results from field measurements in Saanich Inlet. The mercury recovery from the water column, sediment, water with sediment, and the CEE bag walls was only 52.3% of total mercury spiked in the CEE. The losses of mercury by vaporization into the ambient air and diffusion through the wall of the enclosure should be considered. This paper was published in Chinese inOcean. Limn. Sinica,17(4):307–317, 1986.     

THE DIVERGENCE-CONVERGENCE EFFECT OF SURFACE CURRENT AND ITS ACTION ON THE BOHAI SEA

The action of the wind field and the influence of topography can cause divergence or convergence of surface current. The existence of the divergence-convergence effect is proved and the dynamical significance of the divergent or convergent state and its link with many marine phenomena are pointed out. Divergence fields of surface current in the Bohai Sea in winter and summer are obtained by numerical modelling describing the divergence-convergence character of seasonally wind-driven current. The relation between the effect and seasonal marine phenomena is discussed. Study on the divergence-convergence effect of surface current (DCESC)can be an indirect method for testing the calculated results.     

北极加拿大海盆2003年和2008年上层海洋热含量的差异分析

主要利用2003年和2008年两次夏季北极科学考察的CTD数据处理了加拿大海盆上层海洋的热含量(这里上层海洋指的是200m以上的海洋),定量分析了热含量随深度的变化,并比较分析了这两年在夏季海冰融化期间热含量的垂向差异变化,以及影响热含量变化的因素,给出了上层海洋热含量在加拿大海盆的空间分布。2008年与2003年相比最显著的变化是在加拿大海盆开阔水域的增加,这将导致太阳辐射能进入海洋中的能量增加,同时海冰的大量融化带来了大量淡水,这些变化改变了上层海洋的温盐性质。海冰大量融化主要产生两个效应：一是上层海洋的普遍增暖,二是太平洋入流水体的下移。文中还分析了近年来在加拿大海盆中变化显著的次表层暖水现象,由于次表层暖水蕴含着不小的热含量,其在上层海洋热量平衡中的作用不容忽视。     

北极海冰快速减少期间加拿大海盆上层海洋夏季淡水含量变化

北极海冰近年来快速减少,北冰洋淡水含量也出现了急剧变化。加拿大海盆作为北冰洋淡水的主要存储区域,研究其淡水含量变化对于认识北冰洋淡水收支有重要意义。本文根据2003年、2008年中国北极考察以及2004年至2007年的加拿大考察数据进行计算,发现除2006年以外,夏季加拿大海盆淡水含量在此期间每年增加1m以上厚度。增加主要发生在冬季白令海水以上的上层海水中,而在此之下,淡水含量维持在3m左右,没有显著年际差异。在2006年,加拿大海盆西部上层淡水含量略微减少,但东部和北部海域淡水含量仍略有增加。与2003年相比,2008年加拿大海盆中心海区淡水含量增加量最高可达7m。分析表明,近年来的海冰减退对加拿大海盆上层淡水含量的增加起着重要作用,北极涛动(AO)正负相位变化也是控制其淡水含量变化的一个重要因素。而降水、径流以及白令海峡入流水的变化对加拿大海盆淡水含量变化影响较小。     

A study of the microphysical processes in a numerically simulated heavy snowfall event in North China: the sensitivity of different snow intercept parameters

We performed a modeling study of the cloud processes in a heavy snowfall event occurring in North China on 20–22 December 2004. The nonhydrostatic Mesoscale Model (MM5) was used to carry out experiments with the Reisner-2 explicit microphysical parameterizations in four nested domains to test the sensitivity of simulated heavy snowfall to different snow intercept parameters. Results show that while the different intercept parameters do not significantly affect the accumulated snowfall amounts at the surface in either total amount or location, some microphysical characteristics of the modeled heavy snowfall event are impacted. The budget of cloud microphysics is analyzed to determine the dominant cloud processes. In the control experiment (CTL) with the snow intercept (N _os) specified as a function of temperature, the primary simulated hydrometeor is snow, and its mixing ratio is an order of magnitude larger than that of the other cloud species. Relative to CTL, the experiment with a fixed intercept (CON3E6) produced lower snow mixing ratios, more cloud water and graupel mixing ratios. Among the two experiments, while snowfall is slightly smaller in CON3E6, other processes like the rate of graupel fall, condensation and evaporation of cloud water, deposition and sublimation of graupel are all larger in CON3E6 than in CTL. Among CTL, CON3E6, and two more experiments (CON2E7: with a smaller fixed intercept; and NOSQS: N _os a function of snow mass mixing ratio), the budget shows that CON3E6 produces the smallest deposition and sublimation of snow, the largest deposition of cloud ice, and the largest conversion from cloud ice to snow.     

石家庄盛夏一次暴雨空报诊断分析

实时天气系统的时空分布、多个物理量要素都表明2007年7月18日河北省石家庄市东、南和北部将有暴雨天气发生的可能,结果暴雨并没有发生.为了找到暴雨空报的原因,对常规资料和各种数值预报产品进行诊断分析.结果表明:(1)石家庄地区处于2条切变线的中间区域,导致缺少强降水的垂直条件(中、低层的切变线),这是暴雨空报的最主要原因;(2)利用离石家庄最近的邢台探空站的物理量特征来判断石家庄对流发展程度效果较差,这和探空站空间尺度较大有关,这是空报原因之二;(3)缺少有效的数值预报产品是预报失误原因之三:(4)这次邢台、邯郸的暴雨天气系统可定为西南涡类暴雨.利用卫星水汽云图和雷达、国家级自动站要素资料相结合可以大大提高灾害性天气预警能力.     

采用绘图法获取避雷针最小高度的方法

给定保护物高度和保护物高度处的保护半径,求取避雷针的最小高度通常只能通过国标中给出的计算式进行反算。以单支避雷针为例介绍了采用AutoCAD软件绘图获取避雷针最小高度的方法。     

写好电视天气预报解说词的几点体会

电视天气预报解说词不仅应具备新闻特征,注重气象热点,实现事实的真实,而且文字应通俗、易懂、生动、形象和富于文采,以体现艺术的真实,更重要的是善于将气象科学语言转化成电视语言。     

山东省城镇化包容性发展的时空格局

在中国城镇化发展的战略转型期,将“包容性”理念融入新型城镇化道路的建设中,从发展机会平等、发展内容全面、发展成果共享三个维度解析了城镇化包容性发展的内涵,并构建测评指标体系,以山东省为案例进行了实证研究。结果表明：① 2005-2014年,山东省城镇化包容性发展评价值均小于0.5,处于以排斥性特征为主的过渡时期,不同维度的评价值呈现发展机会平等<发展内容全面<发展成果共享的态势;② 只有青岛市进入了包容性特征为主的过渡时期,济南等10地市处于排斥性特征为主的过渡时期,菏泽等6地市处于排斥性发展阶段;③ 各地市综合评价值与发展机会变量的正相关性最显著,说明发展机会不均等是较多地市城镇化包容性发展综合评价值偏低的主要原因。发展机会、发展内容与发展成果的相关性较弱,说明山东省较多地区的城镇化建设投入和成果还未能有效的惠及城乡。理论上,实现了从起点、过程、结果等内在联系紧密的三个维度刻画城镇化的发展水平,完善了城镇化的质量内涵。实践上,可以从不同层面检视城镇化包容性发展的障碍因素,为城镇化的质量提升提供指引。