氢化物-无色散原子荧光光谱法测定微量碲

氢化物—无色散原子荧光光谱法测定黄铁矿及地球化学样品中微量碲，采用硝酸，盐酸，高氯酸分解样品，用浓盐酸将六价碲还原成四价碲，再用硼氢化钾继续还原使碲形成氢化物ＴｅＨ２，在ＡＦＳ１２０１Ｃ原子荧光光谱仪进行测定碲的检示限为０．１８μｇ／ｇ，精密度ＲＳＤ％为６．８％，该方法操作简便、快速、准确、费用低，可应用于大批量地球化学样品的分析。     

Concurrent Determination of U‐Pb Age and REE Mass Fractions of Zircon by High Mass Resolution SIMS

A combined geochronological and geochemical investigation for the same domain of zircon provides valuable information on timing and genesis, particularly in the case of multi‐growth metamorphic zircon. A high spatial resolution concurrent analytical method for zircon U‐Pb age and rare earth element content was successfully achieved in this study, using a multi‐collector secondary ion mass spectrometer (SIMS) at a ~ 8 μm diameter scale. Special instrument parameters were employed, including a high mass resolution of approximately 15000 applied to replace the previous energy filter method, and a dynamic multi‐collector mode used to reduce the measurement time to 18 min per analysis. Six zircon reference materials yielded precise and accurate ²⁰⁶Pb/²³⁸U ages, which are comparable to those obtained by the ordinary mono‐collector method, but with 2–3 times higher spatial resolution. All zircon grains measured in this study showed enriched heavy‐REE (HREE) contents consistent with previously reported values determined by LA and solution ICP‐MS methods. The light‐REE (LREE) mass fractions measured using both SIMS and LA‐ICP‐MS methods in this study, although with quite different volume, show consistent results within uncertainties.     

太平洋年代际振荡对冬季北半球两大洋风暴轴协同变化的可能影响

利用NCEP/NCAR提供的再分析资料和NOAA提供的海温资料分析太平洋年代际振荡(Pacific Decadal Oscillation,PDO)不同位相的年代际背景下北半球海气耦合关系的异常与风暴轴协同变化的联系,主要结果如下:1)冬季太平洋年代际振荡与北半球两大洋风暴轴协同变化之间存在显著的相关关系,当PDO暖位相时,对应两大洋风暴轴南北位置反向的异常变化,其中北太平洋风暴轴偏南且中东部减弱,北大西洋风暴轴偏北且中东部增强,PDO冷位相时相反。2)PDO为暖位相时,对应El Niňo型海温异常,北大西洋海温呈三极型,平均槽脊加强,经向环流增强,极涡收缩,北太平洋风暴轴南压,大西洋风暴轴则北抬,此时欧亚大陆北部和北美大陆大部分地区温度异常升高,亚洲南部、非洲北部及巴伦支海以北的高纬温度异常降低,北美西南部和格陵兰岛附近温度也为异常降低,PDO冷位相时相反。     

冬季赤道中东太平洋海温异常对北半球两大洋风暴轴协同变化的可能影响

利用NCEP/NCAR（National Centers for Environmental Prediction/National Center for Atmospheric Research）和NOAA（National Oceanic and Atmospheric Administration）提供的再分析资料和CPC（National Climate Prediction Center）提供的Nino3.4指数,研究了与赤道中东太平洋海温异常相对应的ENSO（El Nio-Southern Oscillation）不同位相对同期北半球海气耦合关系及两大洋风暴轴协同关系的影响,具体结论如下：1）赤道中东太平洋海温异常与冬季北半球两大洋风暴轴协同变化关系密切,具体表现为海温正异常时对应北太平洋风暴轴和北大西洋风暴轴同时增强,且大西洋风暴轴整体和太平洋风暴轴东部位置南压,海温负异常时则相反。2）海温正异常（El Nio）年时,对流层中层极涡向北太平洋地区伸展,西北太平洋副热带高压增强西移,东亚大槽减弱,高度场异常对应WP（Western Pacific pattern）、EA（Eastern Atlantic pattern）型遥相关的负位相和PNA（Pacific-North American pattern）型遥相关正位相,对流层低层加拿大高压增强,阿留申低压强度增强并向东南方向移动,东亚急流增强东伸,北美急流强度增强,欧亚大陆50°N附近西风增强,经向环流减弱,北半球的斜压异常分布有利于北太平洋东部风暴轴南侧以及中西部风暴轴的有效位能向扰动动能转换,使得风暴轴增强东部南压,北大西洋风暴轴南部斜压增强,使得风暴轴整体偏南,中、西部强度增强。海温负异常（La Nia）年时,海温和环流异常在两大洋基本与El Nio年相反,对应两大洋风暴轴强度同时减弱,同时北大西洋风暴轴整体和北太平洋风暴轴东部北抬。3）海温正异常（El Nio）年时,北美大陆为北暖南冷的异常分布,60°N以南的东亚地区除我国西南外基本为温度异常升高。海温负异常（La Nia）年时,由于高度场和风场异常在欧亚大陆和北美大陆上的异常分布与El Nio年时并不是完全相反,使得温度场异常主要表现在北美南部和东亚北部异常升高。     

Explanatory analysis of the relationship between atmospheric circulation and occurrence of flood‐generating events in a coastal city

The aim of this study is to enhance the understanding of the occurrence of flood‐generating events in urban areas by analysing the relationship between large‐scale atmospheric circulation and extreme precipitation events, extreme sea water level events and their simultaneous occurrence, respectively. To describe the atmospheric circulation, we used the Lamb circulation type (LCT) classification and re‐grouped it into Lamb circulation classes (LCC). The daily LCCs/LCTs were connected with rare precipitation and water‐level events in Aarhus, a Danish coastal city. Westerly and cyclonic LCCs (W, C, SW and NW) showed a significantly high occurrence of extreme precipitation. Similarly, for extreme water‐level events westerly LCCs (W and SW) showed a significantly high occurrence. Significantly low occurrence of extreme precipitation and water‐level events was obtained in easterly LCCs (NE, E and SE). For concurrent events, significantly high occurrence was obtained in LCC W. We assessed the change in LCC occurrence frequency in the future based on two regional climate models (RCMs). The projections indicate that the westerly directions in LCCs are expected to increase in the future. Consequently, simultaneous occurrence of extreme water level and precipitation events is expected to increase in the future as a result of change in LCC frequencies. The RCM projections for LCC frequencies are uncertain because the representation of current LCCs is poor; a large number of days cannot be classified and the frequencies of the days that can be classified differ from the observed time series. Copyright © 2015 John Wiley & Sons, Ltd.     

不同粒径泥沙共存吸附动力学模式研究

天然水体中泥沙组成具有非恒定性和非均匀性,而不同粒径泥沙的吸附能力差异很大.因此.讨论天然水体中泥沙对重金属污染物的自净能力,必须研究不同粒径泥沙共存(即非均匀沙)的吸附模式.通过系统室内静态试验,研究了不同粒径泥沙共存吸附的吸附动力学模式.它表明,不同粒径泥沙共存吸附体系各粒径之间不存在竞争和干扰,共存体系单位重量泥沙的吸附量等于各粒径泥沙单独存在,在相同条件下单位重量泥沙的吸附量乘以其在共存体系中所占份额的和.这在一定程度上解决了天然河流水体泥沙吸附量的计算问题.     

多进程并发在国内气象通信系统的应用

该文介绍了多进程并发在国内气象通信系统中传输新增资料的应用, 针对国内新增气象资料种类繁多 、信息量大 、传输时效要求高、传输频率快等特点, 传输软件通过使用避免僵尸进程产生的方法以及对多种进程间通信技术的比较, 选择了更好满足需求的消息队列通信技术, 使气象资料在国内气象通信系统中的处理时间缩短为原来的 43%, 提高了各种新增气象资料的传输效率 , 为气象资料提供了更好的共享平台, 更好地发挥各种探测仪器的作用。     

实现遥感相机自主辨云的小波SCM算法

随着遥感相机分辨力的提高和幅宽的增大,星上固存和数传带宽面临巨大的挑战。提出一种多分支云判别算法,可控制相机在有云区关机停拍。首先利用计算量较小的光谱阈值判别法对云和地物粗略分类,在不能确定云或地物时,采用纹理分析方法判别。为减小误判可能,算法采用小波SCM提取纹理特征,并提出一种基于ASM和熵的双判别方式。通过对24．5幅遥感图像进行试验验证,证明该算法能快速准确识别云层和地物,总误判率小于5％。     

冬季东亚高空急流季节内协同变化及对我国东部降水的影响

利用ERA-Interim再分析资料,采用滤波和合成分析等统计方法,分析了冬季东亚高空急流的季节内协同变化以及对我国东部降水的影响,结果表明:在季节内尺度(10~90天)中,东亚地区冬季300 hPa逐日纬向风主要表现为准双周振荡(10~30天)。300 hPa低频纬向风异常整体向东传播,高纬的低频纬向风异常向南传播,低纬低频纬向风没有明显经向传播特征。伴随低频纬向西风从里海附近开始向东移动至西北太平洋上空,温带急流向东再向东南移动并且强度先增强再减弱,副热带急流位置没有明显变化,强度演变特征与温带急流变化相反。降水异常对300 hPa风场低频振荡有显著响应,低频降水主要出现在我国东部,随时间向东移动,移至西太平洋附近消失;受低频风场影响,温带急流偏强,副热带急流偏弱时,我国东部高空辐合,地面表现为低频高压,整层有较强下沉气流,地面为东北风控制,不易产生降水;温带急流偏弱,副热带急流偏强时,青藏高原北侧整层一致东风异常,南侧整层一致西风异常,使我国东部高空辐散,地面受低频低压控制,我国东部产生整层上升运动,并且有西南风水汽输送,水汽辐合,我国东部出现低频降水正异常。      

青藏高原和热带印度洋5月热力异常与新疆夏季降水的关系

基于1979-2017年美国国家海洋和大气管理局(NOAA)提供的海表温度资料和美国国家环境预测中心(NCEP)/美国国家大气研究中心(NCAR)提供的大气环流再分析资料以及青藏高原地区149个站点观测资料计算的地表感热通量和新疆气象信息中心提供的全疆81站逐月降水资料等,研究了5月青藏高原和热带印度洋加热对新疆夏季降...