基于20年卫星遥感资料的黄海、渤海海雾分布季节特征分析

目前对海上雾分布的认识多基于沿岸测站和海上船舶、浮标观测,但这些数据非常稀少,且存在代表性和数据质量方面的问题,因此一直缺乏对海雾分布更全面、清晰的了解。卫星遥感数据空间均一、覆盖范围广、质量一致,具有对无云条件下大范围、离岸海雾监测的优势。本文通过分析算法检测出的1989-2008年黄渤海海雾及云的频数、分布百分率信息,得到了黄渤海海雾季节变化的较全面特征。除印证其他资料或研究的结论外,还发现:(1)黄海海雾频数随季节变化的幅度较渤海明显;(2)黄海、渤海海域存在冬季海雾多发时段;(3)海雾生消过程中有覆盖区变化的东传特征;(4)春夏雾季中存在黄海中部和西朝鲜湾两处海雾多发区,其中西朝鲜湾也是全年海雾最多的海域。另外,在样本充足的情况下,通过对检测出的低云、中高云覆盖百分率和海雾频数的分析统计,还能估算出黄海、渤海部分季节20年海雾发生的平均概率。     

一种地市级气象数据库的设计与应用

面向地市级气象业务数据库系统存在的数据管理分散、数据流程不统一等问题,以气象数据为核心,从标准化、规范化数据库建设的角度,提出一种气象数据库系统架构与设计方法。从逻辑结构、物理存储方面对气象数据进行划分,设计了气象数据的物理存储模型和数据统一访问规范。基于RabbitMQ消息中间件和元数据技术实现了多种气象观测资料的采集、传输、入库、备份的统一处理。通过消息数据与元数据的映射关系,增强了多源气象数据处理的灵活性和可扩展性。该系统已经投入业务使用,为气象数据管理和公共服务提供稳定、高效的数据支撑,取得较好的应用效果。     

Effects of modified clay flocculation on major nutrients and diatom aggregation during Skeletonema costatum blooms in the laboratory

Harmful algal blooms(HABs) can elicit several negative effects on aquatic environment(such as depleting the oxygen, blocking the sunlight, destroying the habitats of organisms) and life health(including poisoning/killing marine mammals, birds and human). Among the various control strategies for HABs(physical manipulation needs lots of manpower and expensive equipment, chemicals treatment has some toxic byproduct and high residual, microbial agents only has limited in laboratory research), the coagulation-flocculation of HAB species by modified clay(MC) has been proven to be an effective, lowcost and environmentally friendly method that has been widely applied in the field, particularly in eastern Asia. In order to examine the long-term effects of MC treatment, this study investigated the alternations in seawater of Skeletonema costatum, a high biomass dominant HAB species along the Chinese coast, by comparing the degradation of S. costatum detritus(A1) with the application of MC treatment(A2) and MC treatment in sediment condition(A3). The low dosage of 0.25 g/L MC could efficiently remove 4×108 cells/L of S. costatum cells within 3.5 h(approximately 97% removal). In addition, the results showed that both inorganic and organic nutrients were effectively reduced from seawater by MC particles. Compared to the total nitrogen(TN) and total phosphorus(TP) concentrations in A1 seawater, 44% of TN and 93% of TP in A2 seawater, as well as 72% of TN and 93% of TP in A3 seawater were removed during the onemonth incubation period. Simultaneously, 64% of DISi in A2 and 44% of DISi in A3 significantly decreased( P 0.001). This study demonstrated that MC treatment was able to significantly increase the downward flux of nutrients and delay the release velocity of inorganic nutrient from MC-algae matrix into the overlying seawater, particularly within sediment environment.     

Morphotectonics and tectonic processes of the Southwest Indian OceanEI北大核心CSCD

The Southwest Indian mid-ocean ridge (SWIR) is an ultraslow spreading ridge. Based on the submarine bathymetric data, we develop a new division principle on submarine morphotectonics and subdivide the SWIR into the seven-order tectonic geomorphologic units. Taking its submarine morphotectonics in the middle segment and adjacent seafloors of the mid-ocean ridge between Discovery II and Gallieni transform faults as a sample, this paper systematically analyzes its tectonic evolution, segmentation, segmentation and propagation mechanism, the formation of the central rift valley, the ridge-plume interactions, and the ocean ridge jumping. The results showed that the mid-ocean ridges can be divided into four three-order morphotectonics units (i.e., one-order segments of mid-ocean ridge), from west to east, which are separated by the Andrew Bain, the Prince Edwards, the Discovery II, and the Gallieni transform faults, respectively, corresponding to ridge landforms associated with a strongly hotspot-affected ridge, a weakly hotspot-affected ridge, and a normal ultraslow spreading ridge. Each segment can be further subdivided into three or four secondary segments. This paper focuses only on the segmentation and division from fourth-order to seventh-order morphotectonics units between the Discovery II and the Gallieni transform faults (i.e., the fourth-order morphotectonics unit of mid-ocean ridges can be subdivided into other three secondary units). Here the seventh-order morphotectonics unit consists of segments of laterally-aligned rifts (shear zone), en echelon rifts, and other transverse-faulting structures. The mid-ocean ridge segment experienced three oceanic ridge jumping at about 80 Ma, 60 Ma and 40 Ma, respectively, which were affected by the Marion and Crozet hotspots, or the Madagascar Plateau, etc. The oceanic processes of the SWIR are related to the Gondwana breakup, and its tectonic processes has been analyzed in detail as the periodic pull-apart extension, domino-style half-graben, graben subsidence, oceanic core complex, etc. in axial mid-oceanic ridge since 20 Ma. ©, 2015, Science Press. All right reserved.     

基于GIS的县城城区抗震防灾规划的编制1

当前我国许多县城正在进行抗震规划编制工作,本文结合地理信息系统(GIS),介绍了某县城城区抗震防灾规划的编制及基于GIS的抗震防灾决策系统的开发过程。根据对该规划区建筑物的震害预测,得出震后建筑物的破坏状况及经济损失、人员伤亡情况,为规划编制提供理论依据。     

皖东北地区农村民居抗震性能调查与研究

皖东北地区位于郯庐断裂带中南段附近,具备发生中强地震的构造背景.本文基于现场调查,并结合汶川地震的震害,对该地区农村民居的结构特点、抗震能力及地震安全农居示范工程现状进行了阐述,对农村民居抗震性能的薄弱环节及对策进行了探讨,以期为该地区抗震设防工作提供参考.     

熵理论视角下的生态安全研究

生态危机产生的深层原因是人类经济活动产生的过量熵增,导致自然界产生了过多的熵,复合生态系统进入高熵状态。以熵理论为指导,首先通过建立复合生态系统的熵变模型,判断系统是处在安全、临界还是危机状态,然后对人类社会生态安全的演变进行了熵分析。最后提出克服熵增、实现负熵的途径,即构建低熵发展模式,遵循自然生态规律,发展生态产业,加强生态教育,建立生态安全风险防范体系等,由此来规避生态风险,化解生态危机,维护我国的生态安全。     

The anticorrelation between the hard X-ray photon index and the Eddington ratio in low-luminosity active galactic nuclei

We find a significant anticorrelation between the hard X-ray photon index Γ and the Eddington ratio   L _bol/ L _Edd  for a sample of low-ionization nuclear emission-line regions and local Seyfert galaxies, compiled from literature with Chandra or XMM–Newton observations. This result is in contrast with the positive correlation found in luminous active galactic nuclei (AGN), while it is similar to that of X-ray binaries (XRBs) in the low/hard state. Our result is qualitatively consistent with the spectra produced from advection-dominated accretion flows (ADAFs). It implies that the X-ray emission of low-luminosity active galactic nuclei (LLAGN) may originate from the Comptonization process in ADAF, and the accretion process in LLAGN may be similar to that of XRBs in the low/hard state, which is different from that in luminous AGN.     

Chemical characteristics of wet precipitation at an urban site of Guangzhou, South China

The pH variation and chemical characteristics of rainwater were investigated from January 2006 to December 2006 at an urban site of Guangzhou, South China. The rainwater was typically acidic with a volume-weighted mean pH value of 4.49, which ranged from 3.52 to 6.28. The volume-weighted mean equivalent concentration of components followed the order: SO₄²⁻ > Ca²⁺ > Cl⁻ > NH₄⁺ > Na⁺ > NO₃⁻ > K⁺ > Mg²⁺ > F⁻, indicating that SO₄²⁻, Cl⁻ and NO₃⁻ were the main anions, while Ca²⁺ and NH₄⁺, were the main cations. Ca²⁺ and NH₄⁺ were major neutralization constituents of the precipitation. Furthermore, correlation analysis and principal component analysis method were performed to identify possible common sources of major ions. Sources of the major ions were assessed based on enrichment factor method.