数据稀缺生态系统中多种类质量谱模型的构建

多种类生态模型已经被广泛应用于渔业活动影响应预测和管理措施效果评估。质量谱模型是一种基于生理过程构建的生态模型,该模型为描述鱼类群落在个体摄食变异和随个体发生的生态位迁移提供了一个可行的方法。尽管生态模型在增进生态系统认识上具有重要意义,其应用在数据稀缺的渔业中受到很大限制。作为实践基于生态系统渔业管理(EBFM)的第一步,本研究构建了海州湾鱼类群落的质量谱模型。本研究详述了数据收集和模型参数化的过程,以促进该模型在数据稀缺的生态系统中未来的应用。作为一个范例,研究展示了不同捕捞努力量对生态系统的影响,并采用一套生态指标监测其动态。群落生物量、多样性指数、W指数,大鱼指数(LFI),平均体重和群落质量谱斜率对捕捞压力的响应呈非线性,最大的捕捞强度并非总是对鱼类群落产生最强的影响。本文强调了构建谱模型在生态研究中的的价值和可行性,并讨论了模型的局限性和改进的可能。本研究旨在促进质量谱模型的广泛应用以更好地支持基于生态系统的渔业管理。     

安徽庐枞盆地泥河铁矿床成矿流体性质:来自He-Ar-H-O同位素的证据

安徽庐江泥河铁矿床位于长江中下游成矿带庐枞中生代火山岩盆地,受控于切穿至Moho面的罗河-缺口断裂,矿床具有典型玢岩型铁矿的特征。泥河铁矿床硬石膏-透辉石-磁铁矿阶段流体3He/4He=0.14~0.76Ra(平均0.3548Ra),40Ar/36Ar=262.2~364.9(平均299.3),δ18OSMOW=-2.16‰~5.04‰,δDSMOW=-40.7‰~-34.8‰;硬石膏-黄铁矿-磁铁矿阶段流体3He/4He=0.0108~0.1301Ra(平均0.0697Ra),40Ar/36Ar=221.4~401.4(平均315.1),δDSMOW=-31.8‰~-15.4‰,δ18OSMOW=-2.72‰~1.88‰;高岭石-硬石膏-石英-黄铁矿阶段流体3He/4He=0.0162~0.0223Ra(平均0.0193Ra),40Ar/36Ar=312.5~367.6(平均340.05),δDSMOW=-25‰~-8‰,δ18OSMOW=-6.59‰~-4.89‰。成矿流体的同位素特征显示,幔源流体可能参与了泥河铁矿床早期的成矿作用,后期改造型饱和大气降水逐步加入并占据成矿作用的主导地位。研究结果表明,长江中下游地区中生代强烈的壳幔相互作用,是形成区域巨量金属矿床的重要机制,区域的深大断裂构成了幔源岩浆、幔源物质参与浅部成矿的通道。     

多跨海底管道横流向涡激振动预报模型

基于欧拉-伯努力梁理论确定了多跨管道结构振动方程,采用非线性Van der pol方程描述旋涡脱落的尾流动力特性,利用弹簧模拟两端和中间的复杂边界约束,构建了多跨海底管道横流向涡激振动预报模型。基于模态正交性展开流-固耦合作用方程,对各阶主坐标响应进行数值求解。对比了本模型预报结果与试验结果、软件分析以及DNV规范推荐值,吻合情况比较理想。本模型可为深海多跨管道涡激振动的研究、防范和治理提供有效的分析方法。     

Barotropic processes associated with the development of the Mei-yu precipitation system

The barotropic processes associated with the development of a precipitation system are investigated through analysis of cloud-resolving model simulations of Mei-yu torrential rainfall events over eastern China in mid-June 2011. During the model integration period, there were three major heavy rainfall events: 9–12, 13–16 and 16–20 June. The kinetic energy is converted from perturbation to mean circulations in the first and second period, whereas it is converted from mean to perturbation circulations in the third period. Further analysis shows that kinetic energy conversion is determined by vertical transport of zonal momentum. Thus, the prognostic equation of vertical transport of zonal momentum is derived, in which its tendency is associated with dynamic, pressure gradient and buoyancy processes. The kinetic energy conversion from perturbation to mean circulations in the first period is mainly associated with the dynamic processes. The kinetic energy conversion from mean to perturbation circulations in the third period is generally related to the pressure gradient processes.     

IMPACT OF AIR-SEA INTERACTION ON THE GENESIS OF TROPICAL INCIPIENT VORTEX OVER SOUTH CHINA SEA: A CASE STUDY

Based on 6-hourly sensible heat flux and latent heat flux from the NCEP Climate Forecast System Reanalysis (CFSR) and circulation data from the Japanese 25-year Reanalysis (JRA-25), the initial developing process of tropical cyclone Mindulle (1005) in 2010 has been diagnosed to reveal the impact of air-sea interaction over the South China Sea (SCS) on the genesis of its incipient vortex. The results show that the incipient vortex first occurred east of the Luzon Island on 0000 UTC 20 August, suggesting that the topographic forcing of the Luzon Island for easterly winds over the western Pacific might be one of the factors responsible for the formation of the incipient vortex. During the formation stage of the incipient vortex, strong southeasterlies over the SCS caused warm water of the middle and eastern SCS to flow toward the Luzon Island due to Ekman transport resulting from wind stress, leading to an increase of the sea surface temperature and sensible heat flux into the atmosphere. Although the anomalous sensible heating favored surface pressure to reduce, it was not conducive to the increase of local vorticity associated with the vortex above the heating area because, according to the atmospheric thermal adaptation theory, the anticyclonic vorticity would be created in the lower troposphere due to the decreased vertical gradient of the sensible heating. However, the ascending motions occurred over the eastern area of the anomalous sensible heating due to the augmentation of the vorticity advection with increasing height, causing water vapor to condense in the middle and upper troposphere. In turn, cyclonic vorticity was generated in the lower troposphere due to the increased vertical gradient of the condensation latent heating, resulting in the formation and further growth of the incipient vortex. Therefore, the vorticity creation due to the condensation heating played a dominant role during the subsequent enhancing stage of the incipient vortex.     

Modelling the spatial evolution of map objects by map agents

To overcome the weakness of modelling the relationships between map objects that represent the same geographic entities or phenomena at different times and scales, an agent-based approach is presented to modelling of the spatial evolution of map objects for better understanding of the evolutional process of different maps. Map agents are used to establish and manage the many-to-many corresponding relationships between map objects, and they render map objects active rather than traditionally passive. The evolutions of map objects are modelled by map agents using association and generation relationships to model the connectivity between map objects. This effort reduces the workload of multi-scale map updating by avoiding update of the entire map; instead, it simply allows map agents to detect, perceive and choose suitable behaviours on which to operate and update a spatially evolving object. Experiments of specific examples are presented to demonstrate the feasibility and the effectiveness of our approach.     

数字水深模型多尺度表达方法研究

针对现有数字水深模型(DDM)多尺度表达过程中由于单一固守"安全性"准则所导致的DDM表达精度不高和DDM产品形式单一及使用范围受限的问题,该文在简要介绍二维滚动圆变换及其在等深线化简中的应用的基础上,通过对二维滚动圆变换的维数扩展,提出了滚动球变换的概念。经过大量的计算推导,得到了正(负)向滚动球变换的不同组合方式,实现了既可以顾及"安全性"准则,又能够满足"保真性"需求的DDM多尺度表达方法。该方法可以提高测深数据的利用率和数据表达精度,适应多领域不同层次的DDM应用需求。     

机器学习法在面向对象影像分类中的对比分析

针对如何选择遥感影像面向地理对象分类方法的问题,该文面向地理国情普查中的地表覆盖分类应用,以3个典型区域(山区、平原、城区)的多源高分辨率遥感影像为实验数据,从分类效果、分类精度等方面对比分析3种分类方法(支持向量机、决策树、随机森林)的优劣。在相同影像分割、特征提取、样本采集条件下,通过333组分类实验,得出以下规律:支持向量机分类方法稳定性强,分类速度快,但对特征数的要求高,特征数目与总体精度、地物环境之间的规律性不强,从而增加了特征提取与选择的难度,而随着特征的增加,决策树、随机森林的总体分类精度均为先升高后降低,最后趋于平衡。最后,综合随机森林对特征的优选机制和支持向量机的高分类精度,得到新的组合分类器。     

面向对象的卫星影像积雪信息提取

针对传统基于像元的积雪提取方法的不足,该文以HJ-1B/CCD、IRS遥感影像作为数据源,通过分析HJ-1B影像上的地物特征,提出了先对影像特征合并后进行多尺度分割的积雪提取方法。多尺度分割时,首先将影像分割成多边形对象,然后建立起积雪提取的规则集,进而对积雪信息进行提取。为了验证提取精度,该文对比分析了NDSI方法和本文方法提取积雪的结果,并利用目视解译积雪提取结果定量地进行了精度评价。结果表明:采用本文方法提取积雪具有较高的可靠性和准确性。     

基于多尺度公开版地图数据库的制图综合指标与模型的建立研究

以福建省公开版地图数据库为研究对象,建立1∶250 000、1∶500 000与1∶1 000 000等多尺度公开版地图数据库的制图综合规则。并以居民点和河流要素为例,建立各级比例尺下的选取指标和综合模型,通过综合前后曲线节点数变化、曲线长度比、位置误差及缓冲区限差等指标对河流要素综合结果进行质量评价,获得最适河流综合参数。