Approach to calculating spatial similarity degrees of the same river basin networks on multi-scale maps

Obtaining spatial similarity degrees among the same objects on multi-scale maps is of importance in map generalization. This paper firstly defines the concepts of ‘map scale change’ and ‘spatial similarity degree’; then it proposes a model for calculating the spatial similarity degree between a river basin network at one scale and its generalized version at another scale. After this, it validates the new model and gets 16 points in the model validation process. The x-coordinate and y-coordinate of each point are map scale change and spatial similarity degree, respectively. Last, a formula for calculating spatial similarity degree taking map scale change as the only variable is obtained by the curve fitting method. The formula along with the model can be used to automate the algorithms for simplifying river basin networks.     

中国北方三流域河流—沙漠过渡带地表沉积物化学元素空间差异分析

通过对克里雅河、毛布拉格孔兑以及西拉木伦河三流域的河流-沙漠过渡带地表沉积物的7种常量氧化物以及15种微量元素进行因子分析,结果显示:三个流域之间或不同河段因子分析提取的公因子均可以概括为较稳定的铁锰矿物、较不稳定的长石类和方解石（白云石）类等硅酸盐矿物以及稳定的稀土元素和重矿物等类别;河流间因子分析结果表明,自西向东三个流域沿河地表沉积物的化学元素富集与迁移程度呈递增趋势,化学风化程度增强;流域内因子分析结果表明,自上游至下游,样点化学组成均愈变复杂,不同河段或不同河岸沉积物化学元素空间分布规律与其物源、地貌格局以及水分条件等因素有关;自河床至阶地,不同地貌单元地表沉积物化学元素呈相异的递变规律,这与在距离河道远近不同,物源、动力因素的分配不同有关。     

姚家岭锌金多金属矿床围岩蚀变三维空间定量分析研究

姚家岭锌金多金属矿床是近年来在长江中下游成矿带铜陵矿集区新发现的大型多金属矿床。姚家岭锌金多金属矿床的成矿作用具有多阶段性的特点,矿床范围内围岩蚀变强烈,蚀变类型复杂多样。三维地质信息技术及三维空间分析方法为定量化分析围岩蚀变的空间分布以及与矿化之间的相关关系提供了有利工具。本文基于上述方法,有效地对姚家岭锌金多金属矿床的围岩蚀变的分带性及其与不同矿化之间的关联性行了定量分析。较之于传统研究方法,不仅能快速地对蚀变与矿化的分布特征进行分析,还能从定量的角度获取不同信息之间的规律性和相关性。本文采用的相关方法不但有助于更准确的判定蚀变分带及规律,还可为矿床的成矿模式及找矿模型的建立提供定量化的数据支持。     

分形分维理论在地质灾害发育及空间分布规律中的应用——以长安区滑坡、崩塌地质灾害为例

长安区区内地层岩性、地质构造多样,加之人类经济工程活动、降雨、地震等诱发影响,秦岭北坡及黄土台塬边缘滑坡崩塌地质灾害发育,是陕西省地质灾害较严重的县(区)之一。本文以长安区为研究区域,在对长安区自然地理及区域地质环境条件等资料充分收集的基础上,结合长安区滑坡崩塌灾害点的实际调查资料,详细分析了长安区的滑坡崩塌灾害发育特征及空间分布规律,并采用网络覆盖法,对长安区滑坡崩塌地质灾害的空间分布进行了分形分维计算。求得地质灾害的空间分布分维值为0.876 6,反应出长安区滑坡崩塌地质灾害空间分布特性的复杂性。研究结果表明,分形分维理论能合理评价地质灾害空间分布特征,对类似地区的地质灾害空间分布特征分析具有借鉴意义。     

云南姚安铅银矿床假白榴石斑岩空间分布和组构特征

姚安铅银矿床位于金沙江-哀牢山断裂带东侧的富碱斑岩带内,主要发育正长斑岩、粗面岩、假白榴石斑岩、含斑正长细晶岩等一套杂岩体,其中正长斑岩为主要容矿围岩。通过野外地质勘查、显微镜鉴定、电子探针及X射线微区衍射分析,对假白榴石斑岩的空间分布、岩石矿物学特征进行了综合研究,结果表明,姚安铅银矿床假白榴石斑岩多以脉状、角砾状或呈小岩枝产出,出露在正长斑岩质火山角砾岩的外围,主要分布在角砾岩型铅银矿(化)体的南西侧、F4断裂的北东盘,在空间上与角砾岩筒及外围断裂有关;该矿床的假白榴石具两个世代,早期为灰绿色浑圆粒状假白榴石斑岩的假白榴石斑晶,富Al,晚期为灰-灰白色四角三八面体假白榴石斑岩的假白榴石斑晶,富Si、Na,二者均蚀变成钾长石、高岭石、石英等含水富硅矿物;姚安假白榴石斑岩形成于印度板块与欧亚大陆俯冲碰撞后的板内拉张环境;假白榴石斑岩形成晚于粗面岩、正长斑岩,早于含斑正长细晶岩;假白榴石斑岩与铅银矿(化)体无直接成因联系。     

A Method for Automatically Selecting Aids to Navigation Based on their Spatial Influence Domains

To address the limitations of manually selecting aids to navigation (AtNs) on charts, a method for automatically selecting AtNs based on their spatial influence domains (SIDs) is proposed. First, the associations between the spatial attributes of an AtN are analyzed. Second, an SID of the AtN is defined, and a model of the SID is constructed based on the associations between the spatial attributes. Third, the importance of the location of the AtN is weighted based on the SID model. Fourth, an algorithm to automatically select AtNs based on the maximum coverage of the SIDS of preselected AtNs is developed. Finally, several AtNs are selected automatically using the algorithm. The experimental results demonstrate that (1) the proposed method can automatically select AtNs and the results comply with the requirements; (2) the automatic selection can eliminate the human-induced errors or the inconsistent results of manual selections from different operators; and (3) the efficiency of the proposed method is higher than that of current manual methods.     

Reefs at the edge: coral community structure around Rapa,southernmost French Polynesia

Rapa (27°36′ S, 144°20′ W) is a small (~40 km²) volcanic island isolated in the Southern Austral Archipelago, where direct anthropogenic stressors are extremely limited. Here, we present the results of the first quantitative survey of coral community structure across habitats and depths around the island. Despite its geographical isolation in the depauperate South Central Pacific, its small size and unfavourable environmental conditions (competition with macroalgae, low sea surface temperatures, reduced reef accretion), the diversity of scleractinian corals at Rapa is particularly high (112 species from 32 genera, including 37 species of Acropora) in comparison to other French Polynesian islands and subtropical Pacific locations. Our results indicate that the abundance (>100 colonies per 10 m² recorded at nine of the 17 sampling stations) and cover (>40% at four stations) of corals are relatively high for a marginal reef location. Strong spatial heterogeneity was found, with high variation in diversity, abundance, cover and community composition among stations. Variation in community composition was related to habitat types, with distinct assemblages among fringing reefs within bays, reef formations at bay entrances, and those on the submerged platform surrounding the island. On the platform, a depth gradient was detected, with generic richness, abundance and cover generally greater at deeper stations (18–20 m depth) compared with medium‐depth (10–12 m) and shallow (1–3 m) stations. A gradient was also recorded along bays, with increasing coral diversity and abundance from the bay heads to the bay entrances. The coral community at Rapa was characterized by the presence of several taxa not found in other French Polynesian archipelagos and the rarity of others that are common and abundant in the Society and the Tuamotu islands. Another distinctive feature of reef communities at Rapa is the high cover and dominance of macroalgae, particularly in the shallower parts of the surrounding platform, which probably explains the lower densities of coral colonies recorded there. These characteristics of the diversity and biogeographical composition of coral assemblages at Rapa provide considerable ecological grounds for its conservation.     

基于客观分析的多源卫星叶绿素a浓度产品融合方法研究

本文基于Aqua/MODIS、Terra/MODIS和Envisat/MERIS多源卫星叶绿素a浓度产品,研究了客观分析融合方法,制作了西北太平洋海域(0°~50°N,100°~150°E)叶绿素a浓度融合产品,并从有效数据空间覆盖率和产品精度两个方面对融合方法进行了评价。与单传感器以及欧洲太空局发布的GSM模型业务化融合产品相比,客观分析融合产品空间覆盖率明显提高;与收集的2002-2012年间叶绿素a浓度实测数据比较,GSM模型业务化融合产品的匹配数据点为578个,偏差为-0.20 mg/m3,均方根误差为0.37 mg/m3,客观分析法融合产品的匹配数据点为1432个,偏差为-0.21 mg/m3,均方根误差为0.36 mg/m3。结果表明:本文研究的客观分析融合方法在保证融合产品精度的同时可显著提高产品的空间覆盖率,在海洋水色融合应用前景广阔。     

黄、东海陆架2011年秋季活体浮游有孔虫生态分布

现代活体浮游有孔虫的生态研究是其古环境重建应用的重要基础。根据黄、东海陆架2011年秋季采集的20个垂直浮游拖网样品,分析了该海域浮游有孔虫的秋季生态分布特征。结果表明,黄海秋季基本上没有浮游有孔虫的出现。东海共发现13种活体浮游有孔虫,主要优势属种依次为Globigerinoides sacculifer、Pulleniatina obliquiloculata、Globigerina bulloides、Neogloboquadrina dutertrei和Globigerinoides ruber。浮游有孔虫丰度整体上呈现东南高,西北低的分布格局,这种分布格局反映了浮游有孔虫在黄、东海陆架区的分布主要受外海水影响强弱控制。浮游有孔虫主要属种在东海陆架呈现明显的区域分布差异:暖水种G. sacculifer是秋季陆架海区的主要优势种,其分布格局与总丰度基本一致,相对含量从南至北、从东至西逐渐降低,主要受区域表层海水温度变化的控制。G. bulloides与G. sacculifer呈相反的含量分布变化,其高含量主要出现在东海中陆架,从北往南逐渐降低,此外,在闽浙沿岸也有较高含量,表明了温度和生产力是影响G. bulloides在黄、东海陆架分布的主要因素。秋季P. obliquiloculata和N. dutertrei的高含量主要出现在东海南部中陆架区和济州岛西南黄海暖流影响区,可能受暖水与生产力的共同制约。     

胶州湾表层海水碳酸盐体系的季节变化

根据2007年8月(夏季),11月(秋季),2008年1月(冬季)和2010年4月(春季)在胶州湾海域测得的p H、溶解无机碳(DIC)、总碱度(Alk),以及通过以上参数计算得到的二氧化碳分压(p CO2)的数据,结合现场的化学、水文、生物等参数,探讨和分析了该海域的二氧化碳各参数的分布特征、季节变化和影响因素。结果表明:胶州湾p H、DIC、Alk和p CO2的年变化范围分别为:7.77—8.30,1949.2—2201.8μmol/kg,2033.9—2382.5μmol/kg和89.9—745.3μatm,均呈现明显的时空变化。温度是影响胶州湾碳酸盐体系的主要影响因素之一,同时陆地径流和降水会降低海水碳酸盐体系中各参数的含量,但是人类活动和生物活动也会在一定程度上增加DIC、Alk和p CO2的含量。