Concentration and size variation of condensation nuclei at Mawson,Antarctica     

J. L. Gras  A. Adriaansen  R. Butler  B. Jarvis  P. Magill  B. Lingen 《Journal of Atmospheric Chemistry》1985,3(1):93-106

Condensation nucleus (CN) concentrations have been measured at Mawson (67.6°S, 62.9°E) since mid 1981. Weekly median concentrations have an annual cycle with a maximum of around 300 to 400 cm^-3 in summer and a minimum of a few tens of particles per cm^-3 in winter. In this respect Mawson behaves very much like an Antarctic continental location. Preliminary measurements of the size distribution of CN particles taken over a nine month period suggest a seasonal change in typical particle radius from around 0.01 m in winter to around 0.04 m in summer. Diurnal variation in the CN concentration is generally very weak and does not show any systematic relation to the pronounced diurnal variation in wind-speed at Mawson.Department of Science, Antarctic Division  相似文献   

水准标志沉降的分析计算     

葛彦增  朱晓红  尚贵佳  李玉敏  刘锡纯 《东北地震研究》2002,18(1):31-39

地面荷载的变化，引起了垂直附加应力的变化，通过弹性理论中应变应力的关系，确定了水准标志沉降量的积分表达式，并用梯形法近似地求出。同时，进行了误差估计。  相似文献   

新疆牙哈凝析气田产能变化试井解释   总被引：1，自引：1，他引：0  

蒋漫旗  肖香娇  李保柱  胡永乐  杨思玉  欧阳霆 《现代地质》2008,22(5)

牙哈凝析气田是目前国内已投入开发的规模最大的整装凝析气田,投产以来开发效果很好。但目前牙哈凝析气田全面进入反凝析生产阶段,提气稳产的效果受到很大的影响,生产过程中的矛盾逐渐暴露。使用现代试井解释方法,应用KAPPA公司的Saphir试井解释软件对牙哈凝析气田9口生产井历次压力恢复试井、产能试井进行了试井解释,分析了牙哈凝析气田产能变化规律及反凝析现象对产能变化的影响,得出以下结论:(1)一般储层渗透率为20×10-3μm2,测试点测试产量在25万m3时,为产能测试曲线出现负斜率的分界线;(2)反凝析现象的存在造成试井解释模型多采用径向复合油藏模型。这些对正确认识气藏开发动态及生产特征、加强动态监测技术研究、获得良好的注气效果和显著经济效益起着重要的指导作用。  相似文献   

Allende(CV3)陨石中一种特殊蠕虫状橄榄石集合体的矿物岩石学特征及其成因探讨     

戴德求  林杨挺  缪秉魁  王道德 《矿物岩石》2007,27(1):71-77

在通过对Allende(CV3)碳质球粒陨石的4个光薄片中发现的5个特殊蠕虫状橄榄石集合体(AOA)的岩石学和矿物化学特征研究,证实它们的矿物组合以富橄榄石和霞石为特征,可见少量的金属硫化物。橄榄石颗粒Fa(Fe/(Fe Mg)原子百分比)值范围在34.1 mol%～42.2 mol%,百分标准平均方差(PMD)值为6.1,表明这些颗粒达到了一定的热力学平衡。AOA可能属于星云直接凝聚形成,AOA和细粒CAI(FTA和富尖晶石-辉石型CAI)可能代表了太阳星云从高温到低温连续凝聚的产物。认为AOA的蚀变作用发生在太阳星云中,霞石和铁橄榄石可能是后期水化蚀变的产物,霞石可能替代了AOA中原始的矿物——钙长石和黄长石等。AOA可能在星云中还经历了热蚀变作用的过程,橄榄石和霞石颗粒均具有高的FeO质量分数(29.1%～34.4%,4.04%～9.70%),表明蚀变反应发生在高逸氧度的星云环境下。  相似文献   

热带深对流云砧数值模拟及云凝结核数浓度对其影响的初步试验   总被引：2，自引：6，他引：2  

金莲姬  银燕  王盘兴 《大气科学》2007,31(5):793-804

利用中国科学院大气物理研究所发展的三维强风暴模式，对Egrett Microphysics Experiment with Radiation Lidar and Dynamics（EMERALD）试验期间的一次长寿命热带深对流个例进行对流产生、发展、消亡过程以及云砧的数值模拟，并与实测资料［包括C波段双线偏振雷达图像资料、机载云粒子成像仪（CPI）探测的云砧卷云微物理特性以及激光雷达探测的云砧宏观特性资料］进行了细致的对比，然后通过改变模式中最大云滴数浓度进行有关云凝结核数浓度影响云砧卷云冰晶含水量和数浓度的敏感性试验。模式较好地模拟出系统的一些重要宏观特征，如爆发性增长阶段、各高度雷达水平反射率因子的最大值、对流云主体移动方向、云砧底部和顶部高度。对云砧冰相粒子含水量、数浓度以及平均直径等微观特征的模拟结果与实测也比较接近。对于本文个例而言，异质核化为冰晶形成的最主要方式，其次为过冷云滴的均质核化。敏感性试验结果表明:当云凝结核数浓度增加时，爆发性增长阶段的垂直速度减小，使得对流云从中低层向高层的水物质输送量减少，从而使云砧卷云冰晶的数量减少。  相似文献   

Heterogeneities in the Microstructure and Composition of Aircraft Engine Combustor Soot: Impact on the Water Uptake     

B. Demirdjian  D. Ferry  J. Suzanne  O. B. Popovicheva  N. M. Persiantseva  N. K. Shonija 《Journal of Atmospheric Chemistry》2007,56(1):83-103

Size, morphology, microstructure, chemical composition and hygroscopic properties of aircraft engine combustor (AEC) soot particles are studied by using a combination of several methods, namely atomic force microscopy, transmission electron microscopy, gravimetry, ionic chromatography analysis and wetting observations. From the microstructure and the composition of soot agglomerates, we find that we can separate AEC soot in two fractions having quite different physico-chemical properties: a main fraction of particles containing essentially amorphous carbon with small amounts of oxygen, sulfur and iron and a fraction of impurities characterized by various structures and a large amount of impurities. These properties of aircraft engine combustor soot are compared to those of soot obtained by burning TC1 aviation kerosene in a laboratory burner. It is shown that TC1 soot can be a good surrogate of the AEC main fraction. Such a finding allows us to perform water uptake measurements and to conclude that the AEC main fraction is rather hydrophobic whereas the AEC fraction of impurities is highly hydrophilic The ability of the two fractions of aircraft engine combustor soot to act as cloud condensation nuclei is discussed with respect to their implication in contrail and cirrus formation.Associated to Université de la Méditerranée (Aix-Marseille II) and to Université Paul Cézanne (Aix-Marseille III)  相似文献   

作用于台风系统的动力——热力因子分析   总被引：1，自引：0，他引：1  

杨平章 《气象科学》2000,21(3):348-353

本文导出了台风运动,结构和强度变化的关系方程式,该式表明作用于台风系统的动力－热力因子同时影响台风运动,结构和强度的变化。本文还是导出了台风系统内凝结与降水的不平衡与台风运动的关系方程式,分析该方程所得结果与台风运动的一些实际情况和统计研究结果一致。  相似文献   

Comparison of two methods for ground level vapour sampling and influence of meteorological parameters on its stable isotopic composition at Roorkee,India          下载免费PDF全文

P. Purushothaman  M. S. Rao  B. Kumar  Y. S. Rawat  G. Krishan  Pooja Devi 《水文研究》2014,28(3):882-894

Ground level vapour (GLV) samples were collected at Roorkee, Uttarakhand, India using two methods: liquid condensation (LC) at 0 °C and cryogenic trap (CT) at ?78 °C for the period 2009–2011. The study reveals that there is a considerable fluctuation in stable isotopic composition of GLV throughout the year. The study area receives complex moisture source during different seasons, which is evident from the moisture flux received during different seasons. The isotopic composition of the GLV in both methods shows depleted nature during rainout process. CT method shows exact isotopic signature of GLV because of maximum trapping of air moisture and its condensation, whereas LC method shows depleted or enriched character because of the prevalence of kinetic and diffusive fractionation. The d value shows that LC method acts as magnifier of the CT method and clearly shows seasonal effect than the clustered CT method. Hence, to decipher the original isotopic signature of GLV, isotopic composition of GLV_LC can be converted to GLV_CT by deriving an empirical relationship with changing season and locations. Meteorological parameters show varied behaviour with GLV_{CT and LC} because of moisture sources in all seasons. The GLV_{CT and LC} method shows significant correlation with meteorological parameters when the region is dominated by single moisture source. The GLV_LC method magnifies the correlation with meteorological parameters when the region is influenced by more than one source. The study shows that the GLV_LC methods can be used in place of GLV_CT when the objective is to understand the influence of different moisture sources on GLV. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

三峡库区对局地暴雨和江面大风影响的理论模型   总被引：1，自引：1，他引：0  

卢晨晨  陆维松  陶丽  邵海燕  陈少平 《南京气象学院学报》2011,34(5):555-566

从考虑水汽凝结潜热作用的两维非静力平衡方程组出发,利用江陆边界条件,从理论上求得适用于陆地水体的解析解。结果表明,当0〈k〈1.0℃·km-1时（k为水汽凝结潜热）,江风环流比陆风环流强,两岸比江面容易形成暴雨;当k〉1.0℃·km-1时,江风环流比陆风环流弱,江面比两岸容易形成暴雨;当0.5℃·km-1≤k≤0.9℃·km-1时,江陆面上方低层易出现大风。在江陆风环流中心附近流线出现与锋面类似的间断面,可用于解释雷达图上的海陆面上空类切变线的线状回波。此回波与冷锋相遇,易形成暴雨。  相似文献   

CCN浓度对安徽一次强对流天气影响的数值模拟          下载免费PDF全文

闵锦忠  靳奎峰  陈虹杏  庄潇然  丁伟 《大气科学学报》2019,42(4):542-551

应用WRF(Weather Research and Forecasting)模式,采用NSSL初始CCN数据(C=600 cm~(-3)、k=0.6)及南京北郊观测拟合数据(C=4 000 cm~(-3)、k=0.47)对安徽省一次强对流天气进行模拟。结果发现CCN浓度(CASE2)增大后,所模拟的最大雷达反射率较初始情况(CASE1),在强度和云体宽度上更加接近实况,且CASE2生成了更多强对流单体;CASE2的降水落区较CASE1更为接近实况,且中心雨强大于CASE1,这主要由CASE2中第一个单体更强的降水导致,而两者第二个单体贡献值相近。在过程初期,CASE2中云水、冰晶粒子数浓度比CASE1更大,使得云水粒子冻结时释放出比CASE1更多的热量,从而使得云体发展更为旺盛;两者单位质量中雪晶质量和数浓度相差不大;CASE2比CASE1霰雹粒子比含水量更高,从而在融化过程中形成了更强的冷云降水。  相似文献