HAZE-TO-FOG TRANSFORMATION DURING A LONG LASTING, LOW VISIBILITY EPISODE IN NANJING     

张舒婷  牛生杰 《热带气象学报(英文版)》2016,22(S1):67-77

Haze-to-fog transformation during a long lasting, low visibility episode was examined using the observations from a comprehensive field campaign conducted in Nanjing, China during 4-9 December 2013. In this episode, haze was transformed into fog and the fog lasted for dozens of hours. The impacts of meteorological factors such as wind, temperature (T) and relative humidity (RH) on haze, transition and fog during this episode were investigated. Results revealed significant differences between haze and fog days, due to their different formation mechanisms. Comparison was made for boundary-layer conditions during hazy days, haze-to-fog days and foggy days. Distributions of wind speed and wind direction as well as synoptic weather conditions around Nanjing had determinative impacts on the occurrences and characteristics of haze and fog. Weakened southerly wind in southern Nanjing resulted in high concentration of pollutants, and haze events occurred frequently during the study period. The wind speed was less than 1 m s-1 in the haze event, which resulted in a stable atmospheric condition and weak dispersion of the pollutants. The height of the temperature inversion was about 400 m during the period. The inversion intensity was weak and the temperature-difference was 4°C km-1 or less in haze, while the inversion was stronger, and temperature-difference was about 6°C km-1, approaching the inversion layer intensity in the fog event. Haze event is strongly influenced by ambient RH. RH values increased, which resulted in haze days evidently increased, suggesting that an increasing fraction of haze events be caused by hygroscopic growth of aerosols, rather than simply by high aerosol loading. When RH was above 90%, haze aerosols started to be transformed from haze to fog. This study calls for more efforts to control emissions to prevent haze events in the region.  相似文献   

浅谈辽宁盘锦沿海滩涂开发利用变化监测     

白冰 《测绘与空间地理信息》2016,(3)

伴随着沿海大规模的开发利用,自然生态系统景观格局出现了巨大的变化。在此形势下,对近年来沿海滩涂的规模及开发利用方式进行动态监测具有重要意义。本文就辽宁盘锦沿海滩涂开发利用变化监测的内容、技术方案进行了简要论述,旨在为后期其他城市的监测提供技术参考。  相似文献   

一种倾斜影像外方位元素计算方法     

赵明衍  戴晨光  狄亚南  仇多兵  张伟政 《测绘科学技术学报》2016,(3):263-268

提出一种利用相机POS数据和少量影像数据标定倾斜相机间位置关系并计算倾斜影像粗略外方位元素的方法。首先对选取的垂直和倾斜影像进行影像匹配,获得精确同名点坐标;然后垂直影像同名点对前方交会获得地面点坐标,接着倾斜影像后方交会获得其外方位元素;最后利用倾斜和垂直影像的外方位元素标定子相机间的相对关系,并根据相对关系求出所有倾斜影像的外方位元素。采用AMC580倾斜影像数据进行试验,结果表明:提出方法可求得所有倾斜影像的粗略外方位元素,并验证了外方位元素的直接对地定位精度,证明了该方法的可行性。  相似文献   

近30年江苏地区气候要素相关性变化分析     

彭莹辉  杨玲  程勇 《南京气象学院学报》2016,8(4):380-384

利用江苏省24个台站的1981-2012年的气温、湿度和降水的月平均观测资料,分别计算了每对台站之间的3个气候要素的结构关系和相关函数,用曲线回归分析了结构函数与台站距离的关系,用线性回归分析了相关函数与台站距离的关系,分析与评估江苏省气象台站网密度.通过分析结果发现,各个气象要素的结构函数和相关函数在江苏整个地区不满足各项同性和均匀性,江苏地区的气象台站网设计要根据气候要素进行分区设计.  相似文献   

克里雅河中下游流域地表沉积物的粒度与化学元素空间分布   总被引：3，自引：1，他引：2  

李小妹  严平  吴伟  钱瑶 《地理科学》2016,36(8):1269-1276

通过对克里雅河流域的实地考察、地形测量、取样,分析其流经沙漠过渡带地表沉积物的粒度、化学元素的空间分布,得出以下结论：河流—沙漠过渡带地表沉积物的粒度组成以>2 φ的粒径为主,粒度特征明显表现出风成特点;化学组成上以Si、Al为主,和上陆壳平均化学组成相比,除Ca、Co、As外都有一定的亏损;不同河段自上游至下游,在不同动力条件下,地表物质粒度特征表现出河漫滩砂与阶地风成砂呈相反的递变趋势;不同河段A-CN-K图解及CIA揭示了克里雅河不同河段地表物质化学风化程度均很低,处于较弱的去Na、Ca阶段,其他元素未发生明显的化学风化或迁移,不同河段化学风化程度差异与物源及地貌格局息息相关;同一河段不同地貌单元,随距河道远近不同,粒度特征与化学风化程度呈现出一定的递变规律;克里雅河平均粒径与一些元素的相关性,说明粒径大小与表征化学风化程度数值的大小有一定关系。总之,在不同空间尺度上,克里雅河地表沉积物理化学特征的分异实质上反映风动力和水动力的差异性分选。  相似文献   

查格勒布鲁剖面CGS3a层段主元素记录的巴丹吉林沙漠35 000~25 000 a B. P.季风环境变化     

郭亿华  李保生  牛东风  杨艺  温小浩  司月君 《地理科学》2016,36(6):926-934

对巴丹吉林沙漠东南缘查格勒布鲁剖面该层段的CGS3a层段（Chagelebulu Section 3a）139个样品的主元素——SiO₂、Al₂O₃、TOFE（Fe₂O₃+FeO）进行分析,划分出与地层旋回对应的5.5个化学元素旋回。研究认为：沙丘砂和黄土中SiO₂呈现的峰和Al₂O₃、TOFE、(TOFE+Al₂O₃)/SiO₂和CIA呈现的谷是类似于现代干冷的冬季风在过去多次作用的结果,而嗣后的湖相SiO₂呈现的谷和Al₂O₃、TOFE、(TOFE+Al₂O₃)/SiO₂和CIA的呈现的峰是类似于现代暖湿的夏季风在过去多次作用的结果。即35 000~25 000 a B. P.该沙漠经历了5次冬季风和6次夏季风交替的气候波动,这些气候事件与GRIP冰芯氧同位素记录的D/O（Dansgaard/Oeschger）事件相对应,Heinrich事件也在其中有很好体现。CGS3a层段所记录的千年尺度的气候波动可能是受到了北大西洋气候突变的影响。  相似文献   

IMPLICATIONS FROM CHEMICAL,STRUCTURAL AND MINERALOGICAL STUDIES OF MAGNETIC MICROSPHERULES FROM AROUND THE LOWER YOUNGER DRYAS BOUNDARY (NEW MEXICO,USA)          下载免费PDF全文

ALEXANDRE V. ANDRONIKOV  IRINA E. ANDRONIKOVA  CLAYTON W. LOEHN  BARBARA LAFUENTE  JESSE A. M. BALLENGER  GEORGE T. CRAWFORD  DANTE S. LAURETTA 《Geografiska Annaler: Series A, Physical Geography》2016,98(1):39-59

Hollow magnetic microspherules from along the lower Younger Dryas boundary (c. 12.9 ka bp ) in New Mexico (USA) were studied using scanning electron microscopy, electron probe microanalysis, X‐ray diffraction, and laser‐ablation inductively coupled‐plasma mass spectrometry methods. The shell of the microspherules (10–15% of the spherule's diameter) displays dendritic surface textures, which are likely due to quenching during rapid cooling of molten material. Structurally, multiple single‐magnetite crystals attached together form the bulk of the microspherules. Iron dominates the microspherules’ composition (～90% FeO_tot), Mn is the second most abundant element (up to 0.4% MnO), Al is detected in low concentrations (<0.30% of Al₂O₃). Among the trace elements, the rare earth elements display slightly fractionated patterns with concentrations of 0.1–1.0× CI chondrite. The microspherules contain elevated concentrations of Ni relative to detrital magnetite (up to 435 ppm) and very low concentrations of Ti (down to 5 ppm). Chemical, structural and mineralogical features of the microspherules do not contradict the existing models of the formation during ablation while a meteoroid goes through the Earth's atmosphere. Elevated concentrations of the magnetic microspherules in sediments can be a stratigraphic marker for the lower Younger Dryas boundary in North America.  相似文献   

基于EPS平台的基础地理信息数据重要要素的更新     

孙凯  薛晓轩  徐凯 《测绘与空间地理信息》2017,40(11)

EPS地理信息工作站集信息化测绘生产技术体系、工艺流程、生产工具、数据管理于一体,是GIS技术与CAD技术高度融合的产品,通过该平台可以实现数据航测立体采集、数据采编、入库一体化作业。本文通过探讨基础地理信息数据重要要素的更新,提出了应用EPS地理信息工作站进行重要要素更新的技术方法。  相似文献   

地质要素在工程构筑选址中的影响特性分析     

孙红政  李宏伟  徐哲 《测绘与空间地理信息》2017,(10):199-201,204

新的作战样式催生地质环境下工程构筑选址这一全新的命题。本文探究了地质要素对工程构筑选址的影响,将工程分成三大类,总结三类工程的地质影响要素;通过分析土体、岩体的物理化学和力学性质对工事的作用,总结陆域水体对岩体和建筑材料的物理化学作用,梳理主要的构造、地质灾害和资源类型对工程的影响,明确了六大类地质要素在工程构筑选址中的影响特性,为下一步确定各要素在工程构筑选址中的权重以及构建工程构筑选址信息模型奠定了基础。  相似文献   

MICROSTRUCTURES AND TEMPORAL VARIATION CHARACTERISTICS DURING A SEA FOG EVENT ALONG THE WEST COAST OF THE TAIWAN STRAIT     

张悦  樊曙先  张舒婷  魏锦成 《热带气象学报(英文版)》2017,23(2):155-165

Synoptic systems and microphysical properties associated with a sea fog event are analyzed based on the measurements of visibility, meteorological elements and fog droplet spectrum from a comprehensive field campaign in Xiamen, Fujian province during spring 2013. The influences of meteorological elements on the microstructures of the sea fog are also discussed. The results showed that the wind speed and direction changed suddenly during the intermittent and disperse phases of the sea fog. Liquid water content, number concentration and average diameter varied obviously in the development, mature and disperse phases of the sea fog. The burst re-enforcement of sea fog was accompanied by explosive broadening of fog droplet spectrum; average diameter, number concentration and liquid water content increased sharply; and background meteorological conditions also changed significantly. The microstructures fluctuated intensely due to changes in turbulence, radiation and meteorological conditions at different stages, including nucleation, condensation, coagulation, and evaporation, as well as the discontinuity of spatial distribution of droplets.  相似文献