基于BJ-RUC系统的临近探空及其对强对流发生潜势预报的指示性能初探

缺乏对流天气发生临近时刻的探空观测资料是制约强对流短时预报水平进一步发展的重要因素.随着数值预报技术水平的持续提高,高时空分辨率数值预报输出的模式探空性能越来越好,这为获取对流发生前的临近探空提供了有益的补充.本文针对北京地区2008年夏季20次较强的对流过程,得出北京市气象局BJ-RUC数值预报系统输出的54511站在分析时次(t=0)和预报时效分别为3和6 h的预报偏差均略差于t=0的分析探空,但是此两个时次的预报探空误差仍然处于可接受的范围内.对比20个对流个例54511站分别基于观测和分析或预报的对流不稳定能量、水平风的垂直切变等基本对流参数可以发现t=0时次模式分析探空在趋势和量级上与基于实际探空观测诊断的对流参数均有较好的一致性,基本上能够较为正确地在模式中反映临近对流发生前实际大气的环境特征;但是当考虑实际的预报时效时,t=3和6 h的预报探空能够提前约1和4 h为预报员提供对未来对流发生潜势预报的判断.因此,此两个时次探空更具有实际的业务应用价值.以两个强对流个例为例分析了BJ-RUC系统提供的分析和预报临近探空的性能及其对强对流潜势预报的指示性作用.结果表明,BJ-RUC输出的分析和预报探空对未来对流发生潜势具有较好的指示作用.但依据模式输出的探空变化要对对流发生时间、强度、落区乃至对流类型进行准确预报仍有一定的难度.     

Polycyclic aromatic hydrocarbons in commercial fish and lobsters from the coastal waters of Madagascar following an oil spill in August 2009

Concentrations of polycyclic aromatic hydrocarbons were determined in species of commercial fish and lobsters following an oil-spill just off the protected Madagascan coastline. Samples were collected along the coastline within and outside the affected area. Summed PAH concentrations ranged from 1.9 μg kg⁻¹ to 63 μg kg⁻¹ wet weight, but with no higher molecular weight PAHs (>202 Da) being detected. All concentrations of benzo[a]pyrene, benz[a]anthracene and dibenz[a,h]anthracene were <0.1 μg kg⁻¹ wet weight, well within the EU and UK set limits for the protection of human health. Additionally, samples were calculated as the benzo[a]pyrene toxic equivalency quotient (TEQ) and found to be well below the level of concern in relation to health of human consumers. Evaluation of the biota PAH data indicated the origin of PAH was predominantly petrogenic with >80% arising from oil sources. Profile studies indicate a low-level multisource petrogenic contamination probably representing a pre-spill background for the area.     

Surfactant Enhance DLLME/FO‐LADS: Assay of Malachite Green Level in Aquatic Environment of Trout Fish

Malachite green (MG), a traditional agent used in aquaculture although is not approved; its low cost and high efficacy make illicit use likely. We developed a small‐scale, simple, and sensitive dispersive liquid–liquid microextraction procedure for the assay of trace amounts of MG in aquatic environment of Trout fish. Fiber optic‐linear array detection spectrophotometry with charge‐coupled device detector benefiting from a microcell was used for this purpose. The method is based on enhancement effect of an anionic surfactant on the extraction of MG in to very fine multidroplets of microextraction solvent which made assisted by disperser solvent. Under the optimum conditions, the enrichment factor 77.5 was obtained from a 5‐mL water sample. The calibration graph was linear up to 5 × 10^?7 mol L^?1 with detection limit of 1 × 10^?8 mol L^?1. The relative standard deviation for seven replicate measurements of 4 × 10^?7 and 5 × 10^?8 mol L^?1 of MG were 3.3 and 4.5%, respectively.     

西藏班戈日阿铜多金属矿床地质特征及找矿前景

西藏班戈日阿铜多金属矿床位于班戈-腾冲多金属成矿带,是近年来新发现的矽卡岩型铜多金属矿床,已探明资源量达中型规模。最新研究和找矿成果显示矿带呈北西向展布,受燕山晚期白垩纪花岗岩类岩体侵入作用控制,矿体分布于岩体与下白垩统灰岩地层接触带及附近部位。在空间上,矿床主要分为三个矿段：主矿体分布在矿区中西部,目前在西矿段已圈定5个（条）铜矿体,矿体呈似层状、透镜状,其中最大的Cu13号矿体长221 m,平均厚9 m,沿倾向已控制延深100 m以上,铜品位：0.45%~2.01%,平均0.9%。主要金属矿物为黄铜矿、磁铁矿。中矿段已经圈定3条矿体,成矿元素除铜外,铅、锌、银含量也较高,为铜多金属矿体。矿体呈似层状、透镜状。其中以Cu-23号矿体最大,长达300 m,矿体最宽处达110 m。矿体平均品位Cu1.48%,Pb 1.25%,Zn 2.52%,A g 32.52×1-0 6。本文在矿区地质特征研究的基础上,通过对1：5万水系沉积物测量成果分析,对比中、西矿段成矿条件,对矿区东段进行了预测评价,指出该矿区具有较好的铜多金属找矿前景。同时建议对已圈定的1：5万水系沉积物异常开展1：1万土壤地球化学测量工作,进而圈定该区铜多金属矿带或矿（化）体,为矿区深入勘查工作提供依据。     

西秦岭北缘断裂破裂分段与地震危险性评估

根据最新地质考察和历史地震考证结果,西秦岭北缘断裂带从东到西可划分为宝鸡、天水、武山、漳县、黄香沟和锅麻滩共6个次级断裂段。上述断裂既具有单段破裂,又具有多段组合破裂的特征。利用时间相依的地震潜势概率评估方法,对这6个单段分别进行地震危险性概率评估,其中黄香沟段和漳县段发生单段破裂的可能性最大,天水段发生单段破裂的概率次之。若发生组合破裂,黄香沟段和漳县段组合破裂可能性大。同时,根据沿断裂带的b值扫描图像分析结果显示,黄香沟段和天水附近应力积累较高,这两个地区应是未来发生强震的主要段落,值得关注。     

An East Asian Subtropical Summer Monsoon Index Defined by Moist Potential Vorticity

Based on consideration of both thermodynamic and kinetic features of the subtropical summer monsoon in East Asia,a new index is defined by the moist potential vorticity (MPV) for this monsoon.Variation features of the subtropical summer monsoon over 60 years are analyzed using National Centers for Environmental Prediction/National Center for Atmospheric Research (USA) data from 1948 to 2007.Results show that the new index can well reflect the seasonal,interannual,and interdecadal variations of the East Asian subtropical summer monsoon.Correlation analysis of the new index and precipitation data from 160 stations in China shows that in high-index years,the summer monsoon is strong,and more rain falls in eastern North China,southwestern China,and along the coast of South China and less rain falls in the Yangtze-Huaihe R.basin.In low-index years,the opposite occurs.Lastly,the new index is compared with four established monsoon indices.The new index is found to have an advantage in representing summer rainfall in the Yangtze-Huaihe R.basin.     

Analytic Study on Potential Instability and Spiral Structure of Rain Clusters

This paper presents a study on potential instability and spiral structure of unstable rain clusters.First,we develop a linearized non-axisymmetrical mathematic model for rain clusters in circular cylindrical coordinates and acquire its analytic solution.Second,we discuss the potential instability of non-axisymmetrical rain clusters.Finally,we conclude that spiral structures can exist in rain clusters.Our analysis indicates that potential instability occurs when humid stratification coefficient is less than zero.Unstable growth rate increases with the increase of the absolute value for humid stratification coefficient.The simpler the vertical structure of perturbation,the thicker the inversion layer;additionally,the smaller the radius of the rain clusters,the larger the unstable growth rate.Simulation results agree well with those from observation and forecast.The spiral structure simulated by our model is similar to a radar echo,suggesting that rain clusters with spiral structures can occur in the atmosphere.In addition,they are generally close to the model solution in this work.     

On the Significance and Use of the Generalized Moist Potential Vorticity Equation

In this paper,the continuity and thermodynamic equations including moisture forcings were derived.Using these two equations and the basic momentum equation of local Cartesian coordinates,the budget equation of generalized moist potential vorticity(GMPV) was derived.The GMPV equation is a good generalization of the Ertel potential vorticity(PV) and moist potential vorticity(MPV) equations.The GMPV equation is conserved under adiabatic,frictionless,barotropic,or saturated atmospheric conditions,and it is closely associated with the horizontal frontogenesis and stability of the real atmosphere.A real case study indicates that term diabatic heating could be a useful diagnostic tool for heavy rainfall events.     

华北一次强对流暴雨的湿位涡诊断分析

应用常规地面观测资料、区域加密站降水资料、NCEP再分析资料（水平分辨率为1°×1°,时间间隔为6 h）,对2009年6月8日发生在华北的一次强对流暴雨过程的湿位涡场进行了诊断分析。结果表明：湿位涡的分布对强对流暴雨的发生、落区有较强的指示性作用,MPV1＂正负值区垂直叠加＂的配置是强对流暴雨发生、发展的有利形势。暴雨出现在850 hPa上MPV、MPV1、MPV2正负值过渡带附近,是对流不稳定与斜压不稳定相结合的地区。θse等值线接近垂直的地区有利于垂直涡度的增长,亦有利于强降水发生。     

吐哈盆地西南部铀矿化特征与成矿潜力评价

吐哈盆地西南部艾丁湖斜坡带为一相对稳定的地质构造单元,其上在温湿气候条件下超覆沉积了下侏罗统八道湾组、三工河组和中侏罗统西山窑组。中侏罗统西山窑组主体为一套河流相-河流三角洲相的含煤碎屑岩系;地层泥-砂-泥结构发育良好,砂体岩性主要为成分成熟度和结构成熟度均较低的长石质砂(砾)岩、岩屑砂(砾)岩;岩石为黑色和灰色原生地球化学,具有较强的还原能力。组内层间氧化带广泛发育,总体可划分为完全氧化亚带、其不完全氧化亚带、氧化还原过渡带和原生岩石带,砂岩型铀矿化完全受层间氧化带控制,位于氧化还原过渡带内。目前已在区内找到了十红滩大型层间氧化带砂岩型铀矿床。通过对吐哈盆地西南部构造地质背景、找矿目的层、层间氧化带、水文地质条件、岩石原生地球化学类型及区内已发现铀矿床基本特征的综合分析,指出区内未来仍具有广阔的层间氧化带型铀矿找矿前景。认为十红滩地区作为下一步铀矿勘探基地,主攻层位为中侏罗统西山窑组第一、三岩性段;迪坎儿地段为下一步普查远景区,主攻层位为西山窑组第三岩性段;白咀山、八仙口地段为下一步预查远景区,主攻层位为西山窑组第二、三岩性段。