合成平均图分析在2003年高温天气预报中的应用     

董良淼  陆丹  高安宁 《气象研究与应用》2005,26(3):9-11

大气环流异常对中短期天气变化有着重要影响。利用数值预报产品制作特征要素的合成平均图,是准定量分析前期大气环流异常对中短期天气变化造成影响的有效途径之一,也是对数值预报产品进行合理有效解释应用的一个重要方向。通过利用欧洲中心格点资料制作预报和历史同期合成平均图,结合本地经验指标进行分析比较,并根据临近天气形势进行中短期预报订正,是2003年广西持续性大范围高温天气过程成功预报的关键。  相似文献   

预审单轨自动站地面气象记录月报表的方法   总被引：3，自引：3，他引：0  

龚冬英  黄理  唐竹胜 《气象研究与应用》2008,29(4):73-76

预审员对气象记录月报表进行预审,是报表出站前的最后一道关口,对提高气象资料的准确性有着重要的意义。  相似文献   

Characterization of synthetic hedenbergite (CaFeSi2O6)–petedunnite (CaZnSi2O6) solid solution series by X-ray single crystal diffraction     

Matthias Heuer  Alexandra L. Huber  Geoffrey D. Bromiley  Karl Thomas Fehr  Klaus Bente 《Physics and Chemistry of Minerals》2005,32(8-9):552-563

Clinopyroxenes of the solid solution series hedenbergite (CaFeSi₂O₆)–petedunnite (CaZnSi₂O₆) were synthesized at temperatures of 825–1200°C and pressures of 0.5–2.5 GPa. Compositions were determined by electron microprobe analysis. Selected crystals were investigated by means of single crystal diffraction and structure refinement and the structural distortion was studied depending on the substitution of iron by zinc on the octahedral M1 site. It is shown that the coordination of the M1 site has the most significant effect on M–O bond lengths, with changes on the other sites accommodating this distortion. The mean quadratic elongation and the octahedral angle variance as quantitative measures of the distortion of the coordination polyhedron were correlated with former results of ⁵⁷Fe Mössbauer spectroscopy at 298 K. The results presented now complete an earlier work on synthetic, crystalline powders of the same material and deliver exact structural data that were not possible to obtain by Rietveld refinements on powder data.  相似文献   

全球变化对农业的影响及适应对策   总被引：7，自引：0，他引：7  

林而达  王京华 《地球科学进展》1995,10(6):597-604

政府间气候变化专门委员会是为气候变化框架公约提供科学和技术评价的机构，下设负责气候和温室气体、影响和对策、社会和经济问题三个工作组。它的第一次评价报告完成于１９９０年，修订于１９９２年。为了于１９９５年９月完成它的第二次评价报告，ＩＰＣ组织了世界各国２００多名各领域的科学家（１３名来自中国）分５０多个章节撰写，于１９９５年３月完成了ＩＰＣＣ第二次评价报告的第三稿。本文浓缩介绍了ＩＰＣＣ第二工作组Ｄ  相似文献   

密度分层组合合成技术及影象地质解译     

高民  黄贤芳 《铀矿地质》1987,(2)

密度分层组合成技术是通过对遥感图象密度层次的分折,以突出影象的结构信息为主的一种光孚图象处理方法。根据不同密度层次的多波段遥感图象具有不同类别结构的“信息丰度”的原理,通过对分层片的组合处理,比较成功地对影象信息进行增强和提取,从而获得较好的地质解译效果。实践表明,它不仅对构造解译是有效的,而且对地层、岩性解译也是可行的。在矿床、矿田构造解译力面,它可以获得一些以前没有被认识的信息。本文是基于对我国某铀矿田的卫片进行密度分层处理和解译,提出了矿田受菱形断裂构造块体控制的看法。它对认识铀矿田的构造特点,指导找矿是有一定意义的。  相似文献   

基于客观判识的青藏高原横切变线结构及演变特征合成研究   总被引：1，自引：0，他引：1  

张硕  姚秀萍  巩远发 《气象学报》2019,77(6):1086-1106

利用1981—2016年6—8月每天4次,分辨率为1°×1°的ERA-Interim再分析资料,基于纬向风的经向切变、纬向风速0线和相对涡度3个参数,在计算机客观自动判识青藏高原横切变线（简称高原横切变线）基础上,选取位于33°—35°N的高原横切变线个例13个,采用合成分析技术,研究了高原横切变线结构及演变特征。表明高原横切变线位于青藏高原主体80°—100°E范围内,在500 hPa呈东西走向、水平尺度近2000 km,垂直方向在高原上空可伸展至480 hPa、厚度可达近2 km。高原横切变线出现的环流背景是:500 hPa高纬度两槽两脊,青藏高原两侧分别为带状分布的西太平洋副热带高压（西太副高）和伊朗高压。在动力场上,高原横切变线走向与500 hPa正涡度带轴线走向一致,切变线附近为带状的涡度正值区和上升运动区,对应于无辐散带,辐散/辐合带分布在高原横切变线北/南侧;高原横切变线附近正涡度带垂直可伸展到350 hPa,上升运动伸展至200 hPa,但高原横切变线仅至480 hPa左右,为浅薄的斜压性天气系统,呈现随高度升高向北倾斜的特征。在水汽热力场上,高原横切变线是水汽汇聚带;高原横切变线附近南侧的600—500 hPa存在高假相当位温中心,具有非常明显的高温、高湿特征。高原横切变线从初始产生到发展强盛再减弱的演变过程中,其生命期近4 d,伴随西太副高西移过程,随着高原横切变线附近正涡度带范围增大、强度增强,高原横切变线发展,干冷空气的侵入导致高原横切变线强度减弱甚至消亡。   相似文献   

Unleashing expert judgment in assessment     

《Global Environmental Change》2017

Assessment evaluates accumulated knowledge and its limits. It informs and ideally empowers decisions and actions on complex, contested issues with persistent uncertainties. Applying rigorous expert judgment is an important dimension of assessment. Here we evaluate advances and challenges in approaches to expert judgment in the Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5). We find that revised guidance for author teams improved the development of balanced judgments on scientific evidence across disciplines. In particular, expert judgments underpinning conclusions are more extensively, transparently, and consistently communicated: degree-of-certainty terms are more abundant in AR5 policymaker summaries; wider ranges of possible outcomes are presented with greater inclusion of lower-certainty, decision-relevant findings; and expert judgments supporting conclusions are more comparable across working groups. But challenges in developing and communicating assessment conclusions persist, especially for findings with substantial uncertainties and for subjective aspects of judgments. Based on our evaluations and AR5 lessons learned, we propose a simpler, more rigorous framework for developing and communicating expert judgments in environmental assessment. We also describe practices for reducing expert-judgment biases, for advancing integration of evidence and expert judgment, and for addressing subjective dimensions of expert opinion directly and proactively.  相似文献   

Synthesis and Flocculation Behavior of Cationic Cellulose Prepared in a NaOH/Urea Aqueous Solution     

Lifeng Yan  Hongyun Tao  Prakriti R. Bangal 《洁净——土壤、空气、水》2009,37(1):39-44

Water soluble cationic cellulose was synthesized by the reaction between microcrystalline cellulose and 2,3‐epoxypropyltrimethylammonium chloride in a NaOH/urea aqueous solution. The characterization of the cationic cellulose was performed by NMR spectroscopy, elemental analysis, thermogravimetric analysis, and viscosity analysis. The effects of reaction time and molar ratio of the reagents on the structure of the products were also investigated, and it was found that the degree of substitution (DS) of the cationic cellulose obtained depended on both the ratio of the 2,3‐epoxypropyltrimethylammonium chloride to cellulose and the reaction time. The flocculation capacity of the cationic cellulose was determined with 0.25 wt % kaolin suspension using the standard jar test. Encouraging results were found and cationic cellulose may be applicable for use as a novel flocculant in wastewater treatment.  相似文献   

区域自动气象站资料报表制作与共享系统          下载免费PDF全文

李明香  宋长青  姚文  郭锐 《气象与环境学报》2009,25(2):50-53

区域自动气象站资料报表制作与共享系统是根据我省业务工作的实际需要,使用Delphi语言为编程工具,以“地面气象观测数据文件和记录簿表格式”为标准,以区域自动气象站实时地面气象数据传输文件为基础资料而开发研制的。系统实现了区域自动气象站资料的收集与存储,Z、A、Y文件的生成,月报表和年报表的制作、维护与打印等主要功能,极大方便了区域自动站资料在天气预报、气候分析等工作中的应用。  相似文献   

2007-2008年《地质学报》载文的统计分析   总被引：1，自引：0，他引：1  

怀东  王爱敏 《地质学报》2010,84(12):1854-1858

运用文献计量学的方法,对《地质学报》2007～2008年发表的论文进行统计,基于统计结果,对其载文量、作者合作度、合作率,作者职称学历及工作系统、地区分布、论文受资助情况等指标进行了分析。  相似文献