2015年春季北疆沿天山一带一次强沙尘暴过程分析

利用NCEP1°×1°全球格点再分析资料和常规地面观测资料,对2015年4月27日北疆沿天山一带的沙尘暴天气过程进行了诊断分析。结果表明：乌拉尔山低槽分裂短波槽与中纬度锋区上中亚低槽汇合东移是沙尘暴发生的影响系统,地面冷锋过境是沙尘暴出现的直接原因;前期高温少雨,时值春播期为沙尘暴的发生提供了丰富的沙尘源;中层400 hPa至低层700 hPa强冷平流的入侵,加大了热力不稳定;假相当位温锋区的强迫抬升作用,触发了不稳定能量的释放;300 hPa高空西风急流的增强造成锋生和动量下传,为沙尘暴提供了充足的动力。沙尘暴天气发生在地面冷锋后部西北大风区内、Δp3中心前部、850 hPa强冷平流前部以及850 hPa强上升运动区内。Δp3 ≥10.0 hPa、水平螺旋度≤ -300 m2?s-2对沙尘暴天气的预报有较好的指示意义。     

江淮气旋气候学特征的统计研究

从江淮气旋的定义出发,采用欧洲中期天气预报中心的ERA-Interim再分析资料,运用气旋的客观判定与追踪算法追踪江淮气旋,分析了1979-2010年江淮气旋的气候特征。结果表明:江淮气旋发生的频数有显著的年际变化,但随时间变化的长期趋势并不明显。由于春季冷空气活动频繁,且易与副高西南侧气流汇合形成气旋,因此春季是江淮气旋最活跃的季节,其中5月份江淮气旋发生次数最多;而在冬季,东亚地区受大陆冷高压控制,形势稳定,不易形成气旋,故秋冬季江淮气旋出现较少。受地形和下垫面等因素影响,江淮气旋生成的源地主要位于洞庭湖地区、鄱阳湖地区及大别山区东北侧。43.9%的江淮气旋中心平均降压率为0~-1 h Pa/6h,大多数江淮气旋中心最大降压率为0~-2 h Pa/6h(占66.4%),较难形成暴发性气旋。江淮气旋生命史较短,主要为1~2天。     

南极欺骗岛土壤细菌群落结构和多样性分析

采用基于16S r DNA克隆文库的非培养方法和传统培养方法相结合的手段,对南极欺骗岛土壤细菌群落结构及多样性进行了初步分析。对来自16S r DNA克隆文库的118个阳性克隆进行测序和序列比对,结果显示细菌来自放线菌门(Actinobacteria)、变形杆菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)3大门的39个操作分离单元(OTU),其中优势菌群为放线菌门和变形杆菌门,分别占65.25%和28.81%。放线菌门的主要优势属为鱼孢菌属(Sporichthya)、类诺卡式氏菌属(Nocardioides)、束缚菌属(Conexibacter)、Gaiella和节杆菌属(Arthrobacter)。变形杆菌门的主要优势属为鞘氨醇单胞菌属(Sphingomonas)、硫杆菌属(Thiobacillus)、寡养单胞菌属(Stenotrophomonas)和热单胞菌属(Thermomonas)。采用6种培养基对细菌进行培养和分离,共得到57株菌,来自放线菌门、变形杆菌门、拟杆菌门和厚壁菌门4大门的13个OTU,其中优势菌群为放线菌门和变形杆菌门,分别占57.89%和31.58%。优势属是放线菌门的节杆菌属(Arthrobacter)、雷夫松氏菌属(Leifsonia)和变形杆菌门的假单胞菌属(Pseudomonas)。本论文为研究欺骗岛土壤细菌多样性以及有益菌种资源的开发和利用奠定了基础。     

1950~2011年渤海地区海表风场的季节特征与多尺度变化分析

基于1950~2011年的NCEP/NCAR再分析资料,对渤海10 m风场的风速与风向变化进行多尺度分析。利用小波分析、交叉谱分析等方法对渤海海域的海表风速、风向的变化趋势以及周期进行研究。分析发现：渤海地区海表风的风向与风速除了存在显著的季节性变化特征外,在年际、年代际的变化尺度上也有明显的周期性。风向存在1 a、8.7 a、15.8 a的显著周期,风速存在1 a、6.3 a、15 a的显著周期。风向与风速在时间尺度分别为20 a、5.71 a、2.67 a时存在显著共振周期;共振周期受东亚季风、西太平副热带高压的年际、年代际变化的影响呈现出多尺度变化周期。     

基于灰色理论的穿越管道抗震可靠性研究

本文基于灰色理论，考虑沙土液化，场地的影响，对地震作用下穿越管道的不同破坏程度的可靠性进行了研究，本文的方法较传统方法的加准确，简单，并通过实例证明其实用性和有效性。     

北京市电子地图集的设计与技术实现

在电子地图设计的研究中,“用户界面设计”、“三维景观表达”、“多媒体的使用”、“动态注记”、“图形冲突”和“屏幕地图的交互功能”等都是至关重要的问题。然而在电子地图日益普及的今天,对这些问题的认识还需进一步的研究。本文结合《北京市电子地图集》的创作实践,详细讨论了电子图集的功能设计和界面设计,对以上问题提出了切实可行的的解决方案,并给出了较为理想的试验结果     

《AUTOCAD》和《CORELDRAW》在地质计算机制图中的应用

如何利用通用的计算机图表图象工具软件绘制较复杂的地质图形，一直是地质行业中计算机制图人员棘手的问题之一，ＡＵＴＯＣＡＤ和ＣＯＲＥＬＤＲＡＷ均为功能强大，性能优越，使用方便的图形图象工具软件，但用其制作地质图形却存在着一定的不足，通过总结制作地质图件的经验，得出两种软件可以分阶段使用，其性能可以相互补充，从而绘制出精美的地质图件。     

Analytical Model for the Palaeoenvironmental Evolution of the Nihewan Beds

In this paper, the evolutional characteristics of palaeoclimate and oxidation-reduction conditions as well asacidity-alkalinity environment are discussed by means of the step-regression, cluster, optimal partitioning andcorrelation analyses of CaCO_3, C / P_2O_5, Fe~(2+) / Fe~(3+), pH and Eh values, taking the Xiaodukou section in theNihewan basin as an example. The CaCO_3, C / P_2O_5 and pH were calculated respectively using the optimalpartitioning method. Thus five cold zones and six warm zones as well as five reduction and six oxidation zoneswere distinguished. Then the inductive method was used to produce four numerical groups: 8.10, 8.3-8.4,8.6-8.7 and 8.9-8,97. The above-mentioned results are respectively based on CaCO_3 content, C/P_2O_5 andpH values. From Fig. 3, Tables 1 and 2 it can be seen that the Nihewan Beds were formed mainly under a re-duction and slightly alkaline environment of cold climate, with pH values of 8.3-8.4. Fig. 3 shows that bed 35is approximately near the boundary between the Brunhes and Matuyama polarity epochs, 0.73 Ma in age; bed26 is roughly near the Jaramillo event (base), 0.97 Ma in age; bed 18 coincides roughly with themagnetostratigraphic boundary of 2.00 Ma (?). Bed 13 may be the Pleistocene-Pliocene boundary, 2.48 Ma inage. Thus geochemical zones Ⅰ, Ⅱ, Ⅲ and Ⅳ include respectively cold zones 1; 2 and 3; 4; and 5.     

Seismic acquisition parameters analysis for deep weak reflectors in the South Yellow Sea

The Mesozoic-Paleozoic marine residual basin in the South Yellow Sea (SYS) is a significant deep potential hydrocarbon reservoir. However, the imaging of the deep prospecting target is quite challenging due to the specific seismic-geological conditions. In the Central and Wunansha Uplifts, the penetration of the seismic wavefield is limited by the shallow high-velocity layers (HVLs) and the weak reflections in the deep carbonate rocks. With the conventional marine seismic acquisition technique, the deep weak reflection is difficult to image and identify. In this paper, we could confirm through numerical simulation that the combination of multi-level air-gun array and extended cable used in the seismic acquisition is crucial for improving the imaging quality. Based on the velocity model derived from the geological interpretation, we performed two-dimensional finite difference forward modeling. The numerical simulation results show that the use of the multi-level air-gun array can enhance low-frequency energy and that the wide-angle reflection received at far offsets of the extended cable has a higher signal-to-noise ratio (SNR) and higher energy. Therefore, we have demonstrated that the unconventional wide-angle seismic acquisition technique mentioned above could overcome the difficulty in imaging the deep weak reflectors of the SYS, and it may be useful for the design of practical seismic acquisition schemes in this region.