Isotopic variations in precipitation at Bangkok and their climatological significance

The stable isotopic composition of precipitation from low to mid latitudes contains information about changes of some climatic factors, such as temperature, precipitation and atmospheric circulation patterns. However, the isotopic variations in the area are very complicated because of the combined influences of these factors. Proper interpretation of the patterns of isotopic variations for palaeoclimate reconstructions in this area requires a detailed understanding of these complex stable isotope controls. The isotopic data (δ¹⁸O and δ²D) in precipitation at the International Atomic Energy Agency–World Meteorological Organization Bangkok station were collected and analysed because of the relatively long and unbroken isotopic records and the particular geographical location. The isotopic variations at Bangkok have strong seasonal patterns owing to distinct source regions in different seasons. In summer, the remote sources of water there can influence the δ¹⁸O values significantly, which is verified by the simple Rayleigh model. In winter, the mixing of isotopically distinct air masses with different origins, i.e. the continental and oceanic air masses, accounts for the isotopic variations. In the transition periods of the Asia–Australia monsoon, namely in May and October, the local vapour contribution may play a role in the isotopic ratios. On the interannual time‐scale, the influences of El Niño–southern oscillation (ENSO) and the Indian Ocean dipole (IOD) on isotopic composition are examined. The indications are that both the ENSO and IOD indices have a significant correlation with the δ¹⁸O ratios, and that the δ¹⁸O ratio in summer rains is significantly more enriched (depleted) during the warm (cold) phase of ENSO/IOD events. All the results suggest that it is useful for us in understanding the water cycling process and may be helpful in palaeoclimate reconstruction in this monsoon region. Copyright © 2006 John Wiley & Sons, Ltd.     

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用相似释用方法制作小麦生育期逐旬气候预测

利用气候模式产品、NCEP/NCAR再分析500 hPa旬平均高度资料和河北省冬小麦种植区各测站的逐句降水、气温资料.运用相似释用技术,研制了冬小麦返青—拔节、拔节—抽穗、抽穗—乳熟、乳熟—成熟4个生育期间逐旬气温、降水预测方法,建立了冬小麦各生育期干旱指标预测模型,并在预测业务中应用.预测检验结果表明,用模式产品解释应用方法制作逐旬气候预测是可行的.     

河南省短时强降水及其云团特征分析

根据河南省119个气象站1991-2010年5-9月逐时降水量资料,利用线性趋势和克里金插值等方法,分析了河南省短时强降水及其云团的特征.结果表明:河南省短时强降水自西向东、自北向南呈递增趋势,20.0 ～49.9 mm/h级别的降水在驻马店地区东部和信阳地区西部有明显增多趋势;≥50.0 mm/h级别的降水在周口地区北部有一高值中心.年际变化表明,20.0～49.9 mm/h级别的降水呈显著增加趋势,而≥50.0 mm/h级别的降水呈略增加趋势,但是不显著.月份间的差异非常明显,7月份出现的频次最多,其次是8月份,再次是6月份,5月份和9月份最少.日变化统计表明,上午最少,午后逐渐增加,傍晚和凌晨最多.历年极值雨量7月份出现次数最多,并集中分布在河南省中东部地区,西部地区极值雨量不超过50.0 mm/h,明显低于中东部地区.影响河南省短时强降水的对流云团大致有3个源地6条路径,云团特征可分三种类型,分别为不规则对流云团、圆形或椭圆形云团、带状云系.当有强降水发生时,Tbb值一般很低,但是Tbb值的大小与小时雨量没有很好的相关性.     

FAST故障促动器快速拆换机构设计与研究

针对射电望远镜FAST促动器存在长期承受重载拉力、洼地使用、潮湿多雨、数量大、分布广、设计寿命长等维护不利条件,基于接口便于安装、加载安全可靠、拉杆地面调节、拆换销轴爬梯的设计要点,提出了一种故障促动器快速拆换机构方案,并对关键技术进行研究:包括上连杆开口非封闭C型结构强度、刚度及轻量化有限元分析,抗剪键组件运动控制计算。以上工作为后续快速拆换机构物理样机研制提供了设计方案、分析思路及计算方法,也对解决同类重型加载装置的拆换具有借鉴意义。     

我国古代两种珍稀宝玉石文物分析

为了科学辨别易混淆文物的材质,以蓝绿色和蓝紫色宝玉石文物为例,利用外束质子激发X射线荧光、便携式能量色散X射线荧光、激光拉曼光谱和X射线衍射分析等现代无损科技手段,从安徽蚌埠双墩一号春秋墓、河南洛阳烧沟东汉墓和新疆和田皮山古城唐代墓葬中甄别与鉴定出被误认为是绿松石和琉璃（玻璃）器的天河石串珠和青金石耳？及青金石管饰。简要阐述了这两种彩色宝玉石的矿物学特征及应用历史。这三件彩色宝玉石文物的发现,丰富了中国宝玉石史的研究内容,拓宽了对我国古代先民开采、引进及应用宝玉石的认识。     

乌裕尔河流域颗粒有机碳的来源：碳同位素证据

以2008、2009年所采集的乌裕尔河9个点位水体中的悬浮物为研究对象,对丰、枯水期颗粒有机碳（POC）含量、碳同位素组成（^13C、^14C）及表观年龄进行了系统测试与分析,以期探讨河流中颗粒有机碳来源与流域土壤侵蚀的关系。研究结果表明,该河流中颗粒有机碳（POC）主要来源于未受玉米残体及根系输入影响的深层土壤,且土...     

双频激电在内蒙中部地区矿产评价中的应用

针对工作区地表干燥、基岩裸露、电极接地和供电比较困难等因素,采用双频激电中梯装置方法工作。根据圈定的激电异常组合特征,对激电异常进行了分类和综合解释推断,区分出矿（化）体和含炭质地层干扰异常,以此确定地表工程揭露位置。工程揭露结果与激电异常的解释结果基本一致,说明在一定的条件下,利用激电异常的展布及组合特征区分矿与非矿是可行的。     

Petroleum System of the Fula Depression at the Muglad Basin in the Central African Fault Zone

Petroleum system theory has been used to study characteristics of the Fula depression in the Central African fault zone.In this system,deep lacustrine facies mudstone in the Abu Gabra For-mation of the Lower Cretaceous is a very good source rock,thick deltaic facies sandstone of the Abu Gabra Formation and fluvial facies sandstone of the Bentiu Formation are good reservoir beds,and the mudstone in the Upper Cretaceous Darfur Group is the regional cap rock.The oil search mode and fault block trap seal-off co...