Using synoptic classification and trajectory analysis to assess air quality during the winter heating period in Ürümqi,China

Synoptic patterns identified by an automated procedure employing principal- component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine air quality patterns over¨ Uru¨mqi, China, one of the most heavily polluted cities in the world. Six synoptic patterns representing different atmospheric circulation patterns and air-mass characteristics were classified during the winter heating periods from 2001 to 2008, and seven trajectory clusters representing different paths of air masses arriving at ürümqi were calculated during the winter heating periods from 2005 to 2008. Then air quality was evaluated using these two approaches, and significant variations were found across both synoptic patterns and trajectory clusters. The heaviest air-pollution episodes occurred when ürümqi was either in an extremely cold, strong anticyclone or at the front of a migrating cyclone. Both conditions were characterized by with light winds, cold, wet surface air, and relatively dry upper air. ürümqi was predominately influenced by air masses from the southwest and from local areas. Air pollution index (API) levels were highest for air masses originating from the southwest with a longer path or for the local area, because of transport from semi-desert/desert regions by strong winds and because of local heavy pollution emissions, respectively. The interactions between these two analytical approaches showed that poor diffusion conditions, together with local circulation, enhanced air pollution, besides, regional air-mass transport caused by strong winds contributed to serious air quality under relatively good diffusion conditions.     

百年尺度东海内陆架风暴事件重建:器测记录与沉积记录耦合

未来全球变化可能带来极端事件的强度增加、频度提高,加之海面上升加快,给海岸带防灾减灾工作带来更新防护标准的课题。由于台风的器测记录时间较短,需要从其他载体寻找替代指标以延长台风记录的时间跨度,这样才能更好地估计极端事件的强度一频率关系。陆架泥质区的风暴事件沉积记录和历史文献中的有关灾害记录,是拓展台风记录的两个方向。本文试图通过台风观测记录与沉积记录的耦合,重建百年尺度东海内陆架泥质区的风暴事件沉积记录,并与气象灾害记载的台风暴潮成灾事件相印证,以期探讨陆架泥对台风事件的保存潜力,及其可能反映的台风信息(如路径和强度)。2018年在浙江温岭近海采集了2 m长的柱样沉积物(J1),通过多指标(粒径分布、D₉₀、Zr/Fe、Sr/Al、Ca)综合识别出台风沉积事件;采用放射性同位素²¹⁰Pb定年法确定沉积物的年代序列,将识别的台风沉积记录与器测台风记录通过时间标尺进行耦合分析。结果显示,J1的沉积速率约为1.1 cm/a,年代跨度大约是1836年至2018年;整根柱样共识别出25次台风沉积事件,其中气象观测时期(1950-2018年)有10次台风...     

Structural Design and Protective Methods for the 100 kW Shoreline Wave Power Station

1 .IntroductionThe 1 0 0kWshorelinewavepowerstationofChinaisanOscillatingWaterColumn (OWC)wavepowerdeviceintegratedtoanelectricgrid .ItislocatedattheZhelangTown ( 2 2°39’Nand 1 1 5°34’E) ,ShanweiCityofGuangdongProvince .Theresearchanddevelopmentofthe 1 0 0kWOWCshore linewavepowerstationissupportedbyChina′sNationalKeyTechnologiesR&DPrograminthe 9thfive yearplan .TheconstructionofthestationstartedinJune 1 998andwascompletedinFebruary2 0 0 1 .Uptonow ,ithasbeenoperatingfor2years …     

锦州25—1南油气田主电站的选型设计

主电站作为海洋石油开采平台最重要的核心组成,为整个平台提供动力来源,是保证平台能够正常运转的心脏器官。从机组类型、特点,以及相应的工作原理等几个方面对海洋石油开采平台上的主电站作了简要的描述;依据相关基础数据,结合锦州25—1南油气田的特点,对油气田进行了电负荷分析,得出油气田设计所需要的典型电负荷量以及相关的数据;通过对机组容量、负荷率、备用率、机组占用平台面积、机组重量等几个参数的比对,从往复式发动机电站机组和燃气透平机电站机组中优选出了主电站机组方案。通过对锦州25—1南油气田主电站方案优选的详细阐述,为海洋石油开采平台主电站的选型设计提供参考和借鉴。     

摄影全站系统及其精度评定

摄影全站系统是成熟的数字摄影测量技术与高精度工程测量仪器（全站仪）的集成,可以实现无接触和无控制测量,对摄影测量的发展具有重要的作用。以GFF-7000I摄影全站系统为研究对象,分别对其简单测量模式和标准测量模式进行了不同距离上的精度测试,对摄影全站系统的应用具有一定的指导意义。     

南极乔治王岛地区太阳光照气候特征及影响分析

利用南极长城站 1988—2017 年连续的日照、云量、天气现象、气温和湿度等观测资料,研究 了南极西部乔治王岛 30 a的日照变化特征及其与气象要素的关系。 结果显示,南极地区的日照时 间远少于中低纬度地区,这主要因为该地区常年以阴云天气为主,云层对太阳光的遮挡降低了日 照时间的总量值。2000 年以来,随着总云量和相对湿度的增加,日照时间呈减少趋势。 根据统计分析月平均相对湿度以及每月出现雨、雪、雾、轻雾、吹雪等天气现象和最低气温三0 ℃的天数,发 现液态（ 固态） 现象的发生频率与日照百分率的变化趋势一致（相反） ,即日照百分率低（高） 时,液态现象少（多） ,固态现象多（少） 。     

碟形网箱水动力特性的研究

根据物模实验得到碟形网箱在不同海况条件下的受力并给出了其估算方法和公式及其相关系数的取值,同时总结了碟形网箱的运动特性。     

福建省平潭大风分析

平潭是福建省最大岛屿,处于东亚季风区,是东、西风带交替影响的过度区,其气候季节性特征明显。通过对平潭站1953年建站到2010年的气候资料进行统计分析,结果显示:平潭年大风日数递减趋势明显。通过平潭沿海自动站与本站气象资料对比分析发现,不论是偏北还是偏南风,沿海自动站的风速都大于本站观测值,说明平潭本站风力已经不能真实代表平潭沿海风力。经过仔细研究,进一步总结出平潭本站与沿海自动站风速的相关性,为沿海大风的预报提供科学参考。     

北部湾乌雷站台风浪、风暴增水数值结果的联合概率分析

对1949?2002年北部湾乌雷站台风浪和风暴增水的数值模拟结果进行分析,得出54a的台风浪和风暴增水的极值序列,作出二者联合概率分布图,其分布近似于指数分布,进而运用GUMBELⅡ联合概率分布函数对其拟合,在找出联合概率分布函数过程中分析得出了台风浪和风暴增水不同重现期的单要素极值和联合分布要素极值及相应概率(具体给出),其结果对海洋工程设计有一定的参考价值。     

Validation of Marine Geoid Models by Profile-wise GNSS Measurements on Ice Surface

Ship-board global navigation satellite system (GNSS) measurements are widely used to determine sea surface heights, marine geoid validation, and/or satellite altimetry calibration. However, the use of a vessel could be complicated near coastal areas due to shallow water. Therefore, in the area of sea ice formation, GNSS measurements on the ice surface could be a viable alternative to vessel-borne surveys. Importantly, the ice-covered water is not affected by short-term winds, which otherwise could have systematic influence on the instantaneous sea surface topography. This study tackles methodology and validation of marine geoid models by profile-wise GNSS measurements on ice in an archipelago of the Baltic Sea. The GNSS measurements were carried out on the three ice roads with total length 48 kilometers. The along-route standard deviation between the gravimetric geoid model and profile-wise GNSS heights remained within ±2.1 centimeters.