Aerosol spectra and new particle formation observed in various seasons in Nanjing

The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations exhibited distinct seasonal variations, implying the relations of particle sizes and their sources and sinks. The number concentrations of particles in the nuclei mode （10-30 nm）, Aitken mode （30-100 nm）, accumulation mode （100 -1000 nm） and coarse mode （〉1μm） varied in the order of summer 〉 spring 〉 autumn, summer 〉 autumn 〉 spring, autumn 〉 summer 〉 spring, and spring 〉 autumn 〉summer, re- spectively. The diurnal variation of total aerosol number concentrations showed three peaks in all observed periods, which corresponded to two rush hours and the photochemistry period at noon. In general, the NPF in summer occurred under the conditions of east winds and dominant air masses originating from marine areas with high relative humidity （50%-70%） and strong solar radiations （400 -700 W m-2）. In spring, the NPF were generally accompanied by low relative humidity （14%-30%） and strong solar radiations （400-600 W m-2）. The new particle growth rates （GR） were higher in the summertime in the range of 10- 16 nm h-1. In spring, the GR were 6.8-8.3 nm h-1. Under polluted air conditions, NPF events were seldom captured in autumn in Nanjing. During NPF periods, positive correlations between 10- 30 nm particles and 03 were detected, particularly in spring, indicating that NPF can be attributed to photochemical reactions.     

东亚-太平洋型季节内演变和维持机理研究

利用850hPa的纬向风异常建立一个逐候东亚-太平洋(East Asian Pacific,EAP)型指数,研究其季节内演变特征,发现东亚-太平洋型经向波列是东亚夏季风季节内变化的主要模态.其演变过程为:扰动首先出现在北太平洋中部,并通过正压不稳定过程从基本气流中获得能量而发展,在高层罗斯贝波能量向南频散,激发热带对流异常和赤道罗斯贝波,并相互锁相,因赤道罗斯贝波受β效应影响而共同向西移动.热带对流和环流异常在菲律宾附近达到最强,此时在东亚沿岸出现经向三极型波列,此后中低纬度异常继续向西北方向移动,使降水异常在长江流域能维持较长时间.东亚-太平洋型在东亚发展和维持有以下原因:首先,菲律宾暖水上空的对流和低层环流之间存在正反馈;其次,由于海陆热力差异导致暖大陆和冷海洋之间存在特殊的纬向温度梯度和北风垂直切变,东亚-太平洋型在经向上有向北倾斜的斜压结构,能通过斜压能量转换从平均有效位能中获得能量,同时,也能从经向温度梯度的平均有效位能中获得能量.     

Comparison of the Structure and Evolution of Intraseasonal Oscillations Before and After Onset of the Asian Summer Monsoon

High-resolution satellite-derived data and NCEP-NCAR reanalysis data are used to investigate intraseasonal oscillations （ISO） over the tropical Indian Ocean.A composite evolution of the ISO life cycle is constructed,including the initiation,development,and propagation of rainfall anomalies over the tropical Indian Ocean.The characteristics of ISO over the tropical Indian Ocean are profoundly different before and after the onset of the Indian summer monsoon.Positive precipitation anomalies before monsoon onset appear one phase earlier than those after monsoon onset.Before monsoon onset,precipitation anomalies associated with ISO first initiate in the western tropical Indian Ocean and then propagate eastward along the equator.After monsoon onset,convective anomalies propagate northward over the Indian summer monsoon region after an initial eastward propagation over the equatorial Indian Ocean.Surface wind convergence and air-sea interaction play critical roles in initiating each new cycle of ISO convection.     

麦田怪圈:难解之谜

<正> 英国又现麦田怪圈每年春天,都是英国麦田怪圈来临的季节。各种各样的所谓怪圈一夜之间突然出现在英伦三岛的某一个田地,成为成因不明的神秘现象。就在今年油菜花开遍英国之时,5月22日早     

临时验潮站深度基准面传递模型及其适用性研究

长江口区域瞬时潮汐面受潮汐、径流、风暴潮的耦合作用,具有一定的区域特性。在阐述临时验潮站各种传递模型的基础上,考虑径流季节特性与潮汐特性,利用长期验潮站传递不同时间序列下深度基准面,探讨了各种传递模型在季节特性与潮汐特征组合条件下传递精度及其适用性,提出了长江口区域海图测绘深度基准面传递的优选方案,具有较强的实用性与可操作性。     

钱塘江流域浮游甲壳动物的分布与季节变化

为了阐明钱塘江流域主要河段水生态环境状况,2006年在钱塘江的干流及支流设置10个监测采样点,按季节采集浮游甲壳动物。标本分析显示,共采集浮游甲壳动物到32种,其中枝角类5科19种,春季、夏季、秋季和冬季分别为7种、9种、8种和6种,优势种为远东裸腹溞(Moina weismanni)、短尾秀体溞(Diaphanosoma brachyurum)和脆弱象鼻溞(Bosmina fatalis);桡足类共鉴定3目13种,春季、夏季、秋季和冬季分别为3种、4种、5种和10种,优势种为广布中剑水蚤(Mesocyclops leuckarti)和棘尾刺剑水蚤(Acanthocyclops bicuspidatus)。春季、夏季、秋季、冬季枝角类的密度分别为1.0、9.0、7.5和2.0 ind/L,生物量分别为0.005、1.195、1.254和0.330 mg/L;桡足类的密度分别为30.2、54.7、167.6、45.9 ind/L,生物量分别为1.53、1.56、4.65和0.89 mg/L。枝角类和桡足类的密度和生物量的最大点都出现在浦阳江的进化。     

马赛

马赛是典型的地中海式气候,每年的5月至10月是旅行的最佳季节。马赛一年有300天的充沛阳光,夏季日照时间非常长,几乎要到晚上22点才会天黑。马赛港分老港和新港,老港在城市的港湾,如今成了游艇的码头。新港区在城市的西面,在欧洲仅次于荷兰鹿特丹港,是欧洲排名前五的港口。我们所熟知的《马赛曲》即诞生于此地,它同时还是几千年来东方货品输入西方世界的重镇,所以马赛     

Seasonal variations of phytoplankton diversity in the Coleroon coastal waters, southeast coast of India

The results of an investigation carried out during June 2005 to May 2007 on physico-chemical parameters,species composition and community structure of phytoplankton including Chlorophyll a(Chl-a) at the Coleroon coastal waters(Southeast coast of India) are reported.Air and surface water temperatures(°C) varied from 25.1 to 30.1 and from 24.5 to 28.5 respectively.Salinity values varied from 6 to 28.5 and the pH ranged between 7.0 and 8.3.Variation in dissolved oxygen content was from 3.1 to 7.5 mg/dm-3 while the light extinction coefficient values(LEC) ranged between 3.1 and 10.1 cm.The ranges of inorganic nutrients(μmol/dm-3) viz.,nitrate,nitrite,phosphate and silicate were 10.1-23.4,1.2-8.9,0.2-3.1 and 55-125,respectively.The ranges of Chlorophyll a(μg/dm-3) values was 2.0-7.5.Presently,124 phytoplankton species representing different classes viz:Bacillariophyceae(77),Dinophyceae(19),Cyanophyceae(15),Chlorophyceae(10) and Chrysophyceae(3) were recorded.The phytoplankton cell abundance varied from 0.290 to 111.662 cells/cm-3,with peak diversity(3.38 bits/ind.) during summer season.The maximum abundance was found during summer season coinciding with the stable hydrographical conditions.The seasonal distribution and abundance of phytoplankton are discussed in relation to hydrographical parameters.Canonical Correspondence Analysis(CCA) was applied in this paper for discriminating environmental factors having effect on phytoplankton community at species level.Coleroon coastal water is subjected to long term fluctuations in physico-chemical parameters depending upon the seasonal tidal amplitude and freshwater influx resulting in a continuous exchange of organic,inorganic,plant and animal matters.     

印度洋-太平洋暖池海域表层水温分析

利用1951~2003年HadISST资料集的表层海水温度（SST）资料,讨论了印度洋-西太平洋暖池（IPWP）海域,尤其是印度尼西亚贯穿流（ITF）及其周边海域SST的季节及年际变化的时空特征.研究结果表明,整个研究海域SST的年际变化均与ENSO相关,但印度洋与南海的响应特征与西太平洋的相反且不同步.前者海温变化滞后Nio3指数3~6个月,而热带太平洋西边界和ITF流经海域海温则超前1~3个月.沿ITF及其东印度洋出口,SST的年际变化规律不同于热带印度洋而与太平洋的相似,分析表明其在较大程度上受到ITF海洋桥的影响.在季节尺度上,印度洋和太平洋赤道海域SST的波动规律也有明显不同.以巽他岛弧（苏门答腊、爪哇和小巽他群岛）为界,从赤道西太平洋向西沿ITF流径,太平洋一侧SST的季节变化以0.5a周期的波动占主导,印度洋一侧则以1a周期占主导.     

胶州湾大沽河口潮间带沉积物中叶绿素和有机质含量的季节变化

为了解胶州湾大沽河口潮间带沉积物中底栖微藻和有机质含量的季节变化,于2010年4月至2011年2月,分4次(春、夏、秋、冬)测定分析了沉积物中的叶绿素含量和有机质含量,并分析了沉积物的粒度组成及现场温度。结果表明,表层(0～2cm)沉积物叶绿素a含量为0.42～6.06mg/kg,有机质含量为0.48%～3.71%;次表层(2～5cm)叶绿素a含量为0.13～3.53mg/kg,有机碳质量为0.31%～3.78%;深层(5～8cm)叶绿素a含量为0.14～1.95mg/kg,有机质含量为0.47%～3.72%。经统计检验和Pearson相关性分析得出,胶州湾大沽河口沉积物中的叶绿素a含量春冬两季最高,夏季和秋季最低;叶绿素a含量与深度和温度呈负相关;与所处潮带、有机质含量、粉砂黏土含量在本实验中均无显著的相关性;有机质含量与季节关系不大,高潮带最高,其含量与粉砂黏土含量呈正相关,与叶绿素含量、深度和温度关系不明显。