Depositional System of the Carboniferous Huanglong Formation, Eastern Sichuan Basin: Constraints from Sedimentology and Geochemistry

Using analyses of the lithology, sequences, paleoenvironment, and tectonic setting, the depositional system of the Carboniferous Huanglong Formation in the eastern Sichuan Basin was identified. The lithological characteristics of the Lower Member, Middle Member, and Upper Member were analyzed and classified. Before the use of carbon, oxygen, and strontium isotopes in the analysis, all of the geochemical data were tested for validity. On the basis of the Z values obtained from carbon and oxygen isotopes, the paleoenvironments of the three members were elucidated. Lower Member was dominantly an enclosed marine environment with intense evaporation and little freshwater input into the sea. Middle Member developed in a semi-enclosed to normal marine environment with many rivers. Upper Member was formed in a normal marine environment. The east Sichuan Basin was enclosed by paleouplifts before the deposition of the Huanglong Formation, forming a relatively enclosed depositional setting. Paleogullies developed in the Silurian strata that underlie the Carboniferous rocks; these paleogullies can be identified. On the basis of a comprehensive analysis, we propose that the Huanglong Formation developed in a platform system. Four microfacies were identified: supratidal flat, dolostone flat, grain shoal, and shelf microfacies. The high-permeability and high-porosity characteristics of the grain shoal microfacies are favorable for hydrocarbon accumulation, while the supratidal flat and shelf microfacies developed very few high-quality reservoirs. The paleogullies, in which increased amounts of grain shoal microfacies developed, controlled the distribution of high-quality reservoirs.     

Reconstructed light extinction coefficients using chemical compositions of PM<Subscript>2.5</Subscript> in winter in Urban Guangzhou,China

The objective of this study was to reconstruct light extinction coefficients (b ext ) according to chemical composition components of particulate matter up to 2.5 μm in size (PM 2.5 ). PM 2.5 samples were collected at the monitoring station of the South China of Institute of Environmental Science (SCIES, Guangzhou, China) during January 2010, and the online absorbing and scattering coefficients were obtained using an aethalometer and a nephelometer. The measured values of light absorption coefficient by particle (b ap ) and light scattering coefficient by particle (b sp ) significantly correlated (R 2 > 0.95) with values of b ap and b sp that were reconstructed using the Interagency Monitoring of Protected Visual Environments (IMPROVE) formula when RH was <70%. The measured b ext had a good correlation (R 2 > 0.83) with the calculated b ext under ambient RH conditions. The result of source apportionment of b ext showed that ammonium sulfate [(NH 4 ) 2 SO 4 ] was the largest contributor (35.0%) to b ext , followed by ammonium nitrate (NH 4 NO 3 , 22.9%), organic matter (16.1%), elemental carbon (11.8%), sea salt (4.7%), and nitrogen dioxide (NO 2 , 9.6%). To improve visibility in Guangzhou, the effective control of secondary particles like sulfates, nitrates, and ammonia should be given more attention in urban environmental management.     

大气冰核浓度对对流云降水过程影响的数值模拟

在已有的三维对流云模式的基础上新植入了同质冻结和异质核化方案,结合一次山地雷暴个例,通过敏感性试验来探讨大气冰核浓度对对流云微物理过程和降水的影响。模拟结果表明:①冰核浓度的改变会对对流云的动力场及各水成物粒子产生明显作用。增加冰核浓度,冰相粒子的数浓度随之增加;同时,凝华过程中释放大量潜热导致云中上升气流增强。由于水汽含量一定,各水成物粒子"争夺"水汽,使得云滴、冰晶和霰的增长均受到抑制,难以成为较大尺寸的降水粒子。②冰核浓度的增加,"贝吉龙效应"导致云滴的尺度减小,削弱了云-雨转化过程。雨滴、云滴混合比的减小抑制了雨滴对云滴的收集。同时,小尺度的霰粒子削弱了霰融化为雨滴的物理过程,最终导致地面累积降雨量降低。     

1950-2004年欧亚大陆阻塞高压活动的统计特征

根据阻高的天气学定义,利用1950-2004 年NCEP/NCAR 500hPa 逐日位势高度场、风场再分析资料,检索出近55a欧亚大陆中高纬地区出现阻高1169次.统计表明,阻塞高压中心的频次分布具有明显的季节性地理差异.春季阻高活动多集中在乌拉尔山地区;夏季阻高活动频繁,阻塞形势复杂,阻高频繁活动区域有4个,分别是乌拉尔山地区、贝加尔湖以西地区、贝加尔湖以东地区和鄂霍次克海地区;秋季是阻高发生最少的季节;冬季阻高高发区位于乌拉尔山附近.贝加尔湖地区仅夏季出现阻高的日数就占到全年的69%.夏季欧亚大陆阻塞高压中心逐日累积频次存在明显的随时间东传特征.55a中平均每年夏季欧亚大陆中高纬上空有11d存在双阻形势,占夏季阻高日数的1/5左右.欧亚大陆阻高活动具有明显的年际变化,不同地区的年际变化特征各有不同.     

三峡水库气候效应及2006年夏季川渝高温干旱事件的区域气候模拟

针对2006年夏季川(四川)渝(重庆)地区的高温干旱事件，使用RegCM3区域气候模式，采用双重嵌套和次网格(SUB-BATS)方法，进行中国和三峡地区2005—2006年气候50 km和10 km(通过SUB-BATS方法达到2 km)分辨率数值模拟，并在此基础上进行了三峡地区下垫面改变(三峡水库建成蓄水)的气候效应模拟试验，重点分析了模式对中国和三峡地区夏季气候和气候异常的模拟能力，以及三峡水库对气温和降水的影响。结果表明，模式能较好模拟出中国和川渝地区的气候及以2006年川渝地区高温干旱为代表的气候异常，双重嵌套和SUB-BATS方法的应用，使模式能够提供局地和区域气候更详细的信息。有无三峡水库的对比试验表明，水库对周边区域气温、降水的影响很小，大部分格点上的变化达不到90%统计信度检验标准，气温变化中少数通过检验的格点基本集中于水库水体本身，邻近区域内气温和降水的变化随距库区的距离变远而变得更弱。除了库区本身降温和降水减少外，模拟结果中出现的变化更多表现为模式中出现的噪音。2006年夏季的川渝高温干旱，更多是由于大的环流场造成的，与局地强迫的关系不大，三峡水库在其中所起的作用非常微弱，可以忽略不计。     

平流层温度调整后的辐射强迫的简化计算

采用石广玉[1] 一维辐射对流模式对温室气体浓度变化引起的平流层温度调整后的辐射强迫(ARF)进行了计算。参考文献 [1]的瞬时辐射强迫 (IRF)计算的简化公式的形式 ,将ARF的计算结果表示成简单的经验公式。与使用一维辐射对流模式计算得出的ARF结果的比较表明 ,简化计算公式可以达到很高的精度。     

中国新一代极轨气象卫星——风云三号

风云三号(简称FY-3)是中国第2代极地轨道气象卫星系列.它的第1颗星--风云三号A星(FY-3A)于2008年5月27日上午11时02分33秒在山西太原卫星发射中心发射升空.新一代极轨气象卫星主要是实现伞球、全天候、三维、定量、多光谱遥感,以满足现代气象业务,特别是数值天气预报业务的发展,同时监测大范围气象及其衍生自然灾害和生态环境变化,为研究全球气候变化规律,进行气候诊断和预测提供地球物理参数,为农、林、交通、海洋、水文等多领域提供服务.FY-3A携带11个对地观测仪器,其观测数据通过星地链路进入地面接收站,并在数据处理和服务中心(国家卫星气象中心大楼内)汇集.在强大的计算机和网络支撑下,利用科学算法对仪器遥感数据进行处理,生成各类产品,提供给用户使用.FY-3A发射后,经过半年的在轨测试和试运行,于2009年初正式投入业务运行,卫星和地面系统状态稳定,工作正常.文中较系统全面地介绍了卫星轨道、数传、仪器、数据接收、处理和产品等,尤其分析了星载仪器的主要技术特征,并给出了部分产品应用实例.     

北京气候中心气候系统模式研发进展——在气候变化研究中的应用

较全面地介绍了北京气候中心气候系统模式(BCC_CSM)研发所取得的一些进展及其在气候变化研究中的应用,重点介绍了全球近280 km较低分辨率的全球海-陆-气-冰-生物多圈层耦合的气候系统模式BCC_CSM1.1和110 km中等大气分辨率的BCC_CSM1.1(m),以及大气、陆面、海洋、海冰各分量模式的发展。BCC_CSM1.1和BCC_CSM1.1(m)气候系统模式均包含了全球碳循环和动态植被过程。当给定全球人类活动导致的碳源排放后,就可以模拟和预估人类活动对气候变化的影响。BCC_CSM1.1和BCC_CSM1.1(m)已应用于IPCC AR5模式比较,为中外开展气候变化机理分析和未来气候变化预估提供了大量的试验数据。还介绍了BCC_CSM1.1和BCC_CSM1.1(m)参与国际耦合模式比较计划(CMIP5)的大量试验分析评估结果,BCC_CSM能够较好地模拟20世纪气温和降水等气候平均态和季节变化特征,以及近1000年的历史气候变化,所预估的未来100年气候变化与国际上其他模式的CMIP5试验预估结果相当。初步的分析表明,分辨率相对高的BCC_CSM1.1(m)在区域气候平均态的模拟上优于分辨率较低的BCC_CSM1.1。     

2008年1月南方一次冰冻天气中冻雨区的层结和云物理特征

2008年1月中下旬, 我国南方经历了四次历史罕见的冰冻雨雪天气。本文针对2008年1月25~29日的一次典型冻雨天气过程, 在实测资料、NCEP再分析资料综合分析的基础上, 利用中国气象科学研究院 (CAMS) 中尺度云分辨模式对1月28日~29日的冻雨天气过程进行了数值模拟, 研究了冰冻天气形成的大气层结及云系冻雨区云的宏微观结构特征, 初步分析了冻雨形成的云微物理过程及云物理成因。结果表明, 深厚而稳定的逆温层和低空冷层的存在是大范围冻雨出现的直接原因。此次南方冰冻过程中, 湖南和贵州两地冻雨形成的云物理机理不同, 不同冻雨区上空为两种不同类型的云, 对应两种不同的云微物理结构和大气层结结构。湖南冻雨区云层较厚, 云顶温度较低, 属于混合相云, 云中高层存在丰富的冰相粒子 (雪的比含水量最大)。湖南冻雨在 "冷—暖—冷" 层结下, 通过 "冰相融化过程" 形成, 即在锋面之上的对流层中层水汽辐合中心内形成的雪, 从高空落入暖层, 雪融化形成雨, 再下落到冷层后, 形成过冷雨滴, 最后接触到温度低于 0℃的物体或降落到地面上, 迅速冻结形成冻雨。而贵州冻雨区云层较薄, 云顶温度较高, 属于暖云, 中高层基本无冰相粒子, 低层为云水和雨水 (云水的比含水量最大)。贵州冻雨是在 "暖—冷" 层结下通过 "过冷暖雨过程" 形成的。即水汽沿锋面抬升, 在对流层中低层的水汽辐合中心内, 经过冷却凝结成云滴, 通过碰并云滴增长的雨滴下落到低空冷层, 形成的过冷却雨滴直接冻结形成冻雨。     

CHARACTERISTICS OF UT/LS CARBON MONOXIDE INTRASEASONAL OSCILLATIONS AND THEIR IMPACT FACTORS OVER THE TIBETAN PLATEAU AND ITS ADJACENT AREAS IN SUMMER

The study presented herein investigated the main characteristics of carbon monoxideintraseasonal variability and evaluated its possible impact factors using the upper troposphere and lowerstratosphere (UT/LS) Aura Microwave Limb Sounder (MLS) observations over Tibetan Plateau and itsadjacent areas in summer (June to August) of 2005 and 2006. Observations show a persistent constituentextreme extending up into the UT/LS throughout summer, as well as a temporally reversed phase variationbetween the carbon monoxide and ozone in UT/LS. The intraseasonal oscillations (ISOs) of carbonmonoxide during summer are investigated by using methods of wavelet and band pass filter analysis. It isfound that ISOs over the Tibetan Plateau have periods of 10 to 20 days and 30 to 60 days. The formermainly appeared in upper troposphere while the latter in lower stratosphere. Further analysis shows thatthese two periods of ISOs in UT/LS are mainly in phase to the activities of convection over the south of theplateau and the variation of South Asia High, respectively. The above two factors and their dynamicalcoupling may be responsible for the tracer ISOs at different levels.