黄渤海一次持续性海雾过程形变特征及其成因分析

2016年3月3—5日,渤海和黄海大部出现了一次大范围持续性的海上大雾天气过程。本文从卫星遥感监测上分析海雾在生成、发展和消亡三个阶段的形态演变特征。从海洋气象条件上分析了山东半岛东南近海没有海雾和海雾形态演变的原因。结果表明:(1)在海雾形成初期,在山东半岛东南海域有弱气旋性弯曲,大气层结不稳定,地面形势受低压影响,虽受偏南风控制,但湿度小,无水汽辐合,因此在山东半岛东南近海没有雾。(2)海雾的形成与低层的偏南暖湿气流有关,而这个偏南暖湿气流来源于西北太平洋,雾区对应着水汽辐合区,海气温差为0～1℃的区域与雾区吻合,在海雾发展成熟期,雾顶长波辐射导致雾体降温,出现气温低于海温的现象。(3)925～1000 hPa垂直风切变有利于海雾在逆温层内维持和垂直高度上的发展,形成有一定厚度的海雾。     

2016年初冬陕西一次高架雷暴天气过程分析

利用常规地面高空观测资料、西安和安康多普勒天气雷达观测资料、欧洲中心细网格模式预报等资料对2016年11月22日发生在陕西地区的一次雷暴过程进行诊断分析,结果表明：陕西中南部雷暴区位于地面冷锋后350~500 km的区域内,雷暴区3 km以下是深厚的冷垫,同时中低层存在明显的逆温层,低层是绝对稳定的大气层结,这说明此次雷暴天气为高架雷暴。通过诊断饱和假相当位温、假相当位温、湿位涡和绝对涡度表明不同地区不稳定机制是不同的。西安地区不稳定机制为条件性对称不稳定,安康地区不稳定机制为条件性不稳定。在条件性对称不稳定区域,降雪回波呈现出数个平行带状回波,与0~6 km风切变矢量(西西南风)平行;在条件性不稳定区域,降水回波为小尺度的块状回波。强垂直风切变表明大气斜压性强,中高层暖湿气流增强了大气的湿斜压性,从而使中高层形成条件性对称不稳定,产生倾斜对流;中低层偏南气流输送暖平流和水汽,使得大气较为暖湿,中高层温度平流较弱,大气较干,形成位势不稳定,锋面抬升中低层暖湿大气使其饱和,位势不稳定转化为条件性不稳定,产生垂直对流。不稳定与上升运动及回波高度有着较好的对应关系。     

重力三维聚焦反演在大盐滩深部卤水勘查中的应用

大盐滩地区盐湖企业面临水资源和盐矿资源双重危机,利用重力方法探寻新资源具有重要的实际意义。本文对该区布格重力异常进行三维聚焦反演,获得了大盐滩地区三维剩余密度结构。通过研究发现,大盐滩地区浅地表高低度异常,表征着赋存较为丰富的盐矿资源,但地层中水资源较为贫瘠,浅表水资源主要赋存在山前冲积扇及断裂带内。中深层位不仅具有多个含水层,而且出现多处低密度异常区(T1～T4),可能为深部卤水富集体的反映,是探寻新卤水资源的有利靶区。依此建议在阿尔金山山前冲积带及断裂带内寻找新的淡水资源,并在成矿有利区,开展深部卤水资源勘查工作。     

一种基于FY3D/MERSI2的AOD遥感反演方法

针对目前国产卫星对气溶胶遥感监测应用较少的情况,本研究综合暗象元和SARA算法优势,基于FY-3D MERSI2数据构建了一套气溶胶光学厚度(Aerial Optical Depth, AOD)快速遥感反演方法。首先,引入了传统暗象元算法中的地表反射率经验关系,然后利用AERONET长时间序列的地基观测数据,构建了红波段和蓝波段气溶胶光学厚度、不对称因子和单次散射率之间的关系,最后利用MOD04和AERONET的AOD产品对研究反演结果进行了验证和评估分析。结果发现：① 本研究反演的AOD不仅保持了与MODIS的气溶胶产品空间分布的一致性,而且合理地呈现了AOD的高值分布,改进了MOD04气溶胶产品在云和亮目标方面反演缺失问题;② 利用AERONET地基观测结果对本研究获取的MERSI2的AOD反演结果进行了对比分析,发现二者具有较高的线性相关性,蓝波段AOD线性相关系数超过0.85;③ 利用MERSI2数据完整地捕捉到了2018年3月9—14日京津冀及周边区域的一次重污染过程中气溶胶时空分布变化情况,这也说明了FY3D卫星具备良好的气溶胶遥感监测能力,为我国灰霾监测和预警提供参考依据。本研究对大力发展国产卫星在大气环境遥感的应用有重要参考意义。     

Crustal velocity inhomogeneities along the Hirapur–Mandla profile, central India and its tectonic implications

Wide-angle seismic and gravity data across the Narmada-Son lineament (NSL) in central India are analyzed to determine crustal structure, velocity inhomogeneities and hence constrain the tectonics of the lineament. We present the 2-D crustal velocity structure from deep wide-angle reflection data by using a ray-trace inverse approach. The main result of the study is the delineation of fault-bounded horst raised to a subsurface depth (1.5 km) and the Moho upwarp beneath the NSL. The crust below the basement consists of three layers with velocities of 6.45–6.7, 6.2–6.5 and 6.7–6.95 km/s and interface depths of about 5.5–8.7, 14–17 and 18–23 km along the profile. The low-velocity (6.2–6.5 km/s) layer goes up to a depth of 5 km and becomes the thickest part (13 km), while the overlying high-velocity (6.45–6.7 km/s) layer becomes the thinnest (3 km) and upper boundary lies at a depth of 1.5 km beneath the NSL. The overall uncertainties of various velocity and boundary nodes are of the order of ±0.12 km/s and ±1.40 km, respectively. The up-lifted crustal block and the up-warping Moho beneath the NSL indicate that the north and south faults bounding the NSL are deeply penetrated through which mafic materials from upper mantle have been intruded into the upper crust. Gravity modeling was also undertaken to assess the seismically derived crustal features and to fill the seismic data gap. The lateral and vertical heterogeneous nature of the structure and velocity inhomogeneities in the crust cause instability to the crustal blocks and played an important role in reactivation of the Narmada south fault during the 1997 Jabalpur earthquake.     

井地磁测资料联合反演及应用

井中磁测离深部场源近,能避开浅部干扰,是一种有效的找矿手段,但其控制范围有限;地面磁测采集方便且控制范围大,但老矿区干扰因素多,深部矿体信号弱,不容易解释.文章充分利用地面和井中磁测资料的优点,以二度板状体模型为例,进行井地磁测资料联合反演.通过数值模拟说明了井地联合反演方法的优越性,同时还比较了马奎特法,广义逆法和遗传算法三种不同算法的优缺点,最后将其应用于大冶铁矿实际资料的处理解释,为危机矿山的深部找矿提供了一种有效的方法.     

Structural imprints at the front of the Chocó-Panamá indenter: Field data from the North Cauca Valley Basin, Central Colombia

The northern Andes are a complex area where tectonics is dominated by the interaction between three major plates and accessory blocks, in particular, the Chocó-Panamá and Northern Andes Blocks. The studied Cauca Valley Basin is located at the front of the Chocó-Panamá Indenter, where the major Romeral Fault System, active since the Cretaceous, changes its kinematics from right-lateral in the south to left-lateral in the north. Structural studies were performed at various scales: DEM observations in the Central Cordillera between 4 and 5.7°N, aerial photograph analyses, and field work in the folded Oligo-Miocene rocks of the Serranía de Santa Barbara and in the flat-lying, Pleistocene Quindío-Risaralda volcaniclastic sediments interfingering with the lacustrine to fluviatile sediments of the Zarzal Formation.The data acquired allowed the detection of structures with a similar orientation at every scale and in all lithologies. These families of structures are arranged similarly to Riedel shears in a right-lateral shear zone and are superimposed on the Cretaceous Romeral suture.They appear in the Central Cordillera north of 4.5°N, and define a broad zone where 060-oriented right-lateral distributed shear strain affects the continental crust. The Romeral Fault System stays active and strain partitioning occurs among both systems. The southern limit of the distributed shear strain affecting the Central Cordillera corresponds to the E–W trending Garrapatas–Ibagué shear zone, constituted by several right-stepping, en-échelon, right-lateral, active faults and some lineaments. North of this shear zone, the Romeral Fault System strike changes from NNE to N.Paleostress calculations gave a WNW–ESE trending, maximum horizontal stress, and 69% of compressive tensors. The orientation of σ1 is consistent with the orientation of the right-lateral distributed shear strain and the compressive state characterizing the Romeral Fault System in the area: it bisects the synthetic and antithetic Riedels and is (sub)-perpendicular to the active Romeral Fault System.It is proposed that the continued movement of the Chocó–Panamá Indenter may be responsible for the 060-oriented right-lateral distributed shear strain, and may have closed the northern part of the Cauca Valley, thereby forming the Cauca Valley Basin.Conjugate extensional faults observed at surface in the flat-lying sediments of the Zarzal Formation and Quindío-Risaralda volcaniclastic Fan are associatedwith soft-sediment deformations. These faults are attributed to lateral spreading of the superficial layers during earthquakes and testify to the continuous tectonic activity from Pleistocene to Present.Finally, results presented here bring newinformation about the understanding of the seismic hazard in this area: whereas the Romeral Fault Systemwas so far thought to be themost likely source of earthquakes, themore recent cross-cutting fault systems described herein are another potential hazard to be considered.     

济阳坳陷孤西负反转断层形成演化定量研究及其油气地质意义

以高精度三维地震资料和钻井资料为基础,对研究区断裂构造进行精细解释,确定孤西断层为"薄底型"的、且表现为北段缓而南段陡、并向西倾的负反转构造;通过回剥技术和平衡剖面等定量分析技术对垂直穿越孤西断层的典型地震剖面研究揭示,孤西断层在J3-K1时期断层性质发生改变,由逆断层反转变为正断层,且在印支、J3-K1和Ek-Es4时期剖面拉伸率分别为-4%,17.2%和18.5%;沿孤西断层走向方向不同位置计算其断层活动速率表明该断层整体经历了负反转运动。以上述分析为基础,论文从烃源岩、圈闭、储集岩和油气运移角度,探讨了孤西负反转断层在孤岛潜山油气成藏方面的重要意义。     

联合星载光学与SAR图像的城市大面积建筑物高度快速提取

星载高分辨率光学图像与SAR图像广泛应用于城市建筑物高度提取,但光学图像存在缺少相关卫星参数的情况,而SAR图像则存在散射特征不完整以及提取效率低等缺陷。针对以上问题,本文提出一种联合高分辨率星载光学与SAR图像的城市大面积建筑物高度快速提取方法。首先,结合支持向量机(SVM)和形态学阴影指数(MSI)快速提取光学图像中的阴影并自动测量阴影长度;之后选择多个合适样本,基于模型匹配法从SAR图像中提取高度;最后将高度与阴影长度作线性回归分析,建立数学模型来提取其他建筑物的高度。该方法将不同卫星系统的数据和特征相结合,互相弥补各自缺陷,不仅提高了效率、降低了成本,同时满足精度要求。     

基于改进人工蜂群算法的概率积分法参数反演

针对传统算法在反演概率积分法参数时易发散且难以获得全局最优解的问题,提出利用自适应人工蜂群算法反演概率积分法参数。根据该算法在求解过程中收敛速度快,获得全局最优解的特点,将参数反演问题转化为组合优化问题,建立了自适应人工蜂群算法的概率积分法预计参数反演流程,并将计算结果与实际值进行对比分析。通过理论分析与实验证明,自适应人工蜂群算法反演概率积分法参数精度高,较最小二乘法和模矢法拟合效果好,可应用于矿山开采沉陷预计。