西北太平洋九州-帕劳海脊北部KPR12岩芯40万年来有机碳来源、埋藏特征及其环境响应

西北太平洋海陆相互作用强烈,受黑潮和亚洲大陆风尘输入影响显著,是研究海洋沉积物中有机碳埋藏与陆源输入、海洋初级生产力和海洋环境演化关系的理想靶区。本研究基于采自九州-帕劳海脊北部的重力活塞647 cm长的KPR12岩芯,分析了总有机碳（TOC）、总氮（TN）、有机碳稳定碳同位素组成（δ¹³C_TOC）、蛋白石（Opal）以及粒度等指标,初步探讨了近40万年来轨道尺度沉积有机碳的来源、埋藏特征及其影响机制。岩芯的TOC含量平均值为0.214%,呈冰期较高、间冰期较低的旋回特征。岩芯沉积物粒度的不同端元反映了研究区风尘输入大致呈冰期较高的趋势。岩芯的δ¹³C_TOC（-25.24‰~-21.04‰,平均值为-22.59‰）显示有机质以海源为主（约62%）,海源有机碳含量趋势与TOC的变化一致。研究区不同时期陆源物质的输入受风尘输送和黑潮的综合控制,黑潮增强可能对该区间冰期陆源有机碳贡献的升高有一定影响。岩芯中TOC与Opal含量的相关性分析表明,海洋初级生产力可能不是控制该岩芯有机碳含量变化的主要原因。冰期-间冰期旋回中的深层水通风条件、黑潮和北太平洋中层水的发育以及陆源细颗粒物质输入可能共同影响着本区沉积有机碳的降解与埋藏保存。

     

末次冰盛期-全新世东海陆坡滑塌沉积的地质年代与沉积学证据

基于东海陆坡区OT12-01孔长度为5.35 m沉积物AMS 14C测年、高分辨率粒度分析和XRF岩芯元素扫描数据,识别出了末次冰盛期(LGM)至全新世期间发生的多次滑塌事件。研究发现,OT12-01孔全新世晚期沉积层缺失,LGM至全新世期间呈现AMS 14C年龄模式频繁倒转、沉积物粒度、元素比值垂向上多处突变或"错动"等特征,保存了LGM至全新世非连续的沉积记录。OT12-01孔沉积物主要来源于低海平面时期的长江/黄河物质,OT12-01孔是由中国大陆陆源物质在东海陆架经水动力分选,细颗粒被搬运至东海陆坡后,发生多次滑塌形成。LGM时期物源供给是OT12-01孔形成滑塌沉积的重要因素,末次冰消期海平面快速上升可能是高频滑塌沉积的触发原因,而低海平面时期甲烷水合物溢出、频繁的地震和火山喷发可能是海底滑坡作用发生的诱因。     

机载激光测深系统强度数据AGC补偿异常区域识别及改正

机载激光测深系统（Airborne Laser Bathymetry,ALB）因集成了具有独特水体穿透能力的绿波段（532 nm）而被广泛用于水深测量。除地形数据外,ALB还记录了地物目标的辐射特性（后向散射强度）,可用于条带配准、海底底质分类和几何建模。然而,由于自动增益控制（Automatic Gain Control,AGC）设计局限,增益值调整存在延缓,对于裸露岩石、水域等高返回、低返回目标较多的海岛海岸带区域,强度补偿异常问题格外突出。针对该问题本文设计了一种基于双向移动的局部加权强度改正方法,提出索引共享机制辅以地形信息实现有效强度数据精确提取;以扫描周期为依据进行扫描线分割,通过柯尔莫可洛夫−斯米洛夫检验进行强度补偿异常区识别;通过对邻近扫描线和邻域强度联合加权进行强度改正,保证强度细节的同时较好地消除与邻域强度偏差,独特的双向移动策略能有效削弱改正不足积累造成的强度改正精度下降问题。实验证明该方法能有效解决AGC补偿异常问题,相较于改正前,改正后的强度数据平均绝对百分比误差降低了约0.27,均方根误差下降了约693,异常区强度与邻域强度偏差控制在26 DN（Digital Number）以内,得到高质量强度图像。     

导航电子地图增量更新服务及关键技术研究

以移动通讯数据传输技术、网络技术和时态数据库技术为基础,构建了导航地理信息的变化发现、分析甄别、采集、加工、处理、存储和发布服务一体化的增量式更新服务模式、技术、软件、质检和标准体系,论述了多源数据融合、时空模型及空间关系的动态实时维护、多尺度增量式导航电子地图综合处理、路径规划和质检方法等关键性技术,实现了导航电子地图近实时更新服务。     

北康-曾母盆地中中新世以来层序地层样式特征探讨

开展地震资料解释,分析上超、下超、顶超等地震反射终止关系、不整合面以及沉积趋势,识别出北康-曾母盆地中中新世以来14个三级层序界面。在层序界面内部,通过层序地层内幕结构刻画和原形剖面恢复,并结合地层堆砌方式,在北康-曾母盆地中中新世以来的层序地层内,划分了海进、高位正常海退、强制海退和低位正常海退4种成因单元。通过进一步研究该4种成因单元内地层结构和相分布关系,提出北康-曾母盆地中中新世以来的3种层序地层样式,即陆架边缘富砂型三角洲进积楔、退积型生物礁和陆架边缘富砂-富泥型退积楔,其中,沉积物源供应量充足且可容空间减小时,发育富砂的三角洲进积楔,陆架边缘-斜坡-盆地区域发育含砂深水扇;而可容空间增量远大于沉积物供应量时,发育退积型生物礁和富砂-富泥退积楔,斜坡-盆地区域含砂深水扇欠发育。     

Climatic response of thick leaf spruce (Picea crassifolia) tree-ring width at different elevations over Qilian Mountains, northwestern China

Tree-ring cores of thick leaf spruce (Picea crassifolia) taken from four sites at different elevations, in the middle of the Qilian Mountains, in the arid and semi-arid region of northwestern China, were used to develop four tree-ring width chronologies using standard dendrochronological methods. Results indicate that with increasing altitude the chronologies’ year-to-year variations decreased. Hence, the sensitivity of the tree-ring chronologies to climate decreases with altitude. Further analysis showed that the significant limiting factor on tree growth is spring precipitation. Measurements of stomata density and leaf dry weight suggest the species’ ecological adaptation strategy changes with elevation. At high elevation the metabolic rate of thick leaf spruce decreases, thus showing the effect of the climate.     

基于CEI的飞船交会对接远程导引段的轨道确定方案

探讨了CEI技术在飞船交会对接远程导引段的高精度定轨与实时监控的能力。仿真结果表明:精密定轨中采用可视弧段较长的单站可使相对位置精度达百米以内,速度达厘米/秒级。采用单一绝对扩展卡尔曼滤波器的方案进行实时轨道计算,采用滤波稳定后固定模糊度的方法可以使相对轨道位置精度达十米级,速度精度达厘米/秒级,事后及实时的轨道精度均满足远程导引段的精度指标。     

High-efficiency calculation method for watershed rainfall-runoff routing using one-dimensional dynamic wave equations

Efficiency in solving the Saint-Venant equations for watershed rainfall-runoff routing is important in flood hydrology. This paper presents a high-efficiency numerical solution of one-dimensional dynamic wave equations (HEDWE) for watershed rainfall-runoff routing, in which the full momentum equation is written as a quadratic equation with only one unknown variable Q, water depth is derived from the continuity equation using the two-step predictor-corrector method, and the discrete scheme is the explicit upwind scheme. The results of numerical tests showed the HEDWE approach has several major advantages. 1) It is a stable numerical method, even for an initially dry area. 2) Its computational efficiency is higher than 4.76E+05 times/s. 3) It can be used for overland flow, river flow, and combinations thereof. The primary disadvantages of the HEDWE approach are its unsuitability for rapidly varying flow, such as dam-break floods.     

摩擦作用对西南低涡扰动的影响

西南低涡是对流层下层的中尺度扰动。本文在零级近似条件下,采用p坐标系的基本方程组,在边界层内设计两层模式。通过一定的简化方程组后,得到:当Z≤1/2[kL~2/(μ~2Knu~*)] 时,摩擦效应具有二重性,一方面使扰动减弱;另一方面使扰动增强,而前者的影响略大于后者,最终使扰动消失。频率随高度Z的降低而增加。当Z>1/2[kL~2/(μ~2Knμ~*)]时,摩擦作用甚微,几乎可以忽略不计。频率虽然有两个值,但随高度Z的增加,他们趋于一个常值。     

Observational evidence for solar coronal decimetric radio pulsations with very short periods

Using the decimetric (700–1500 MHz) radio spectrometer and the synchronous observational system with high temporal resolution at four frequencies (1420, 2130, 2840 and 4260 MHz) of Yunnan Observatory, two rare events were observed on 2001 June 24 and 1990 July 30. The former was a small radio burst exhibiting pulsations with short periods (about 29, 40 and 100 ms) in the impulsive phase. The latter was a large radio burst, which at 2840 MHz produced radio pulsations with period of about 30 ms. This paper focuses on pulsations with very short periods in the range of 29–40 ms. The mechanism of generation of such pulsations may be modulation of radio radiation by the periodic trains of whistler packets originating in unstable regions of the corona. Alternatively, these pulsations can be attributed to wave-wave non-linear interactions of electrostatic upper hybrid waves driven by beams of precipitating electrons in flaring loops.