BCK-代数上的(λ1,λ2)-广义模糊关联理想

给出了BCK代-数上(λ1,λ2)-广义模糊关联理想,模糊关联理想的概念并在此定义下推出了它们的一些重要性质。     

Indirect effects of the intertidal burrowing crab<Emphasis Type="Italic">Chasmagnathus granulatus</Emphasis> in the habitat use of Argentina’s South West Atlantic salt marsh birds

The burrowing crab,Chasmagnathus granulatus, is the dominant benthic macroinvertebrate of southwest Atlantic salt marshes and tidal flats, having strong ecosystem engineering effects by direct and indirect effects on soil, vegetation, invertebrates, fishes, and birds. Vegetation structure is a main component for bird habitat selection, since greater habitat complexity generates higher niche diversity. This environmental complexity can be modified by species interactions or disturbance events (i.e., by crabs), in turn modifying the associated community. The bird species of salt marshes of the southwest Atlantic are highly dependent on these ecosystems. We assessed the effects of the burrowing crab on the structure of the cordgrass,Spartina densiflora, marshes, and how these changes affected the composition and diversity of birds. This study was conducted at the Mar Chiquita Coastal Lagoon, Argentina (37°40′S, 57°23′W).S. densiflora marshes were classified within three categories: marshes without burrowing crabs, marshes with low burrow densities, and marshes with high burrow densities. We made vegetation and bird surveys during spring beforeS. densiflora produce seeds and in summer when seeds are abundant. We also manipulated inflorescence (i.e., spike) density (a variable affected by crabs) to assess the effect on bird habitat use. The highest inflorescence density ofS. densiflora and highest bird diversity were recorded at low burrow densities. Cover and height ofS. densiflora were negatively correlated with burrow density. The number of bird species and the number of red-capped wren-spinetail,Spartonoica maluroides, were negatively related with cover and height ofS. densiflora. Experiments confirmed that granivorous species used areas with higher spike densities, a variable related to crab burrow density. Burrowing crabs directly and indirectly affect the cover, height, spike density, and morphologic characteristic of seeds ofS. densiflora marshes. These effects indirectly affect the bird community that uses these marshes, being negatively related toS. maluroides and total bird abundance, and positively related to bird diversity.     

Field and geochemical characteristics of the Mesoarchean ( 3075 Ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in supra-subduction oceanic crust

The Mesoarchean (ca. 3075 Ma) Ivisaartoq greenstone belt in southern West Greenland includes variably deformed and metamorphosed pillow basalts, ultramafic flows (picrites), serpentinized ultramafic rocks, gabbros, sulphide-rich siliceous layers, and minor siliciclastic sedimentary rocks. Primary magmatic features such as concentric cooling-cracks and drainage cavities in pillows, volcanic breccia, ocelli interpreted as liquid immiscibility textures in pillows and gabbros, magmatic layering in gabbros, and clinopyroxene cumulates in ultramafic flows are well preserved in low-strain domains. The belt underwent at least two stages of calc-silicate metasomatic alteration and polyphase deformation between 2963 and 3075 Ma. The stage I metasomatic assemblage is composed predominantly of epidote (now mostly diopside) + quartz + plagioclase ± hornblende ± scapolite, and occurs mainly in pillow cores, pillow interstitials, and along pillow basalt-gabbro contacts. The origin of this metasomatic assemblage is attributed to seafloor hydrothermal alteration. On the basis of the common presence of epidote inclusions in diopside and the local occurrence of epidote-rich aggregates, the stage I metasomatic assemblage is interpreted as relict epidosite. The stage II metasomatic assemblage occurs as concordant discontinuous layered calc-silicate bodies to discordant calc-silicate veins commonly associated with shear zones. The stage II metasomatic assemblage consists mainly of diopside + garnet + amphibole + plagioclase + quartz ± vesuvianite ± scapolite ± epidote ± titanite ± calcite ± scheelite. Given that the second stage of metasomatism is closely associated with shear zones and replaced rocks with an early metamorphic fabric, its origin is attributed to regional dynamothermal metamorphism. The least altered pillow basalts, picrites, gabbros, and diorites are characterized by LREE-enriched, near-flat HREE, and HFSE (especially Nb)-depleted trace element patterns, indicating a subduction zone geochemical signature. Ultramafic pillows and cumulates display large positive initial ε_Nd values of + 1.3 to + 5.0, consistent with a strongly depleted mantle source. Given the geological similarities between the Ivisaartoq greenstone belt and Phanerozoic forearc ophiolites, we suggest that the Ivisaartoq greenstone belt represents Mesoarchean supra-subduction zone oceanic crust.     

The 1997–1998 Activity of Volcán de Colima,Western Mexico: Some Aspects of the Associated Seismic Activity

Volcán de Colima, the most active volcano in Mexico, had a climactic episode on 20 November, 1998. On this date, a dome formed on the small summit crater during the previous few days, collapsed generating block-and-ash flows. The event was preceded by almost twelve months of seismic activity, which continued afterwards for several more months. We analyzed the main seismic activity, which occurred from 20 March, 1998 to 31 March, 1999. The seismicity was dominated by volcano-tectonic earthquakes before the climax, and subsequently by hybrid and long-period earthquakes. We determined the frequency of events for the entire period, and located most of the volcano-tectonic events. To assess the possibility that these earthquakes were generated by the same source, they were tested for their similitude through cross correlation in the time domain. Six groups of similar events, or earthquake families, were generated. The members of these families appeared before the 20 November event, apparently ceasing afterwards. We examined the location of the families' events with respect to an existing gravity model in which an anomalous body of negative density contrast suggests the presence of the magma chamber. Most of the family events occur on top of the anomalous body, which suggests they were associated with the passage of magma through the feeding conduits of the volcano.     

The Role of the Solar Cycle in the Relationship Between the North Atlantic Oscillation and Northern Hemisphere Surface Temperatures

The North Atlantic Oscillation （NAO） is one of the leading modes of climate variability in the Northern Hemisphere. It has been shown that it clearly relates to changes in meteorological variables, such as surface temperature, at hemispherical scales. However, recent studies have revealed that the NAO spatial pattern also depends upon solar forcing. Therefore, its effects on meteorological variables must vary depending upon this factor. Moreover, it could be that the Sun affects climate through variability patterns, a hypothesis that is the focus of this study. We find that the relationship between the NAO/AO and hemispheric temperature varies depending upon solar activity. The results show a positive significant correlation only when solar activity is high. Also, the results support the idea that solar activity influences tropospheric climate fluctuations in the Northern Hemisphere via the fluctuations of the stratospheric polar vortex .     

多星拼图的再处理技术

由于不同静止气象卫星的观测时间、分辨率及红外通道的红外扫描辐射计的光谱响应函数和空间响应函数都不尽相同,因此,将两颗静止气象卫星的红外云图融合在一起而形成的多星拼图,就会在交界处呈现不连续性,图像上表现为一条明显的拼缝且拼缝的两边亮度不一致。本文利用“直方图匹配方法”对多星拼图进行处理,消除了亮度不均匀现象,提高了图像的整体视觉效果。     

初值中云变量对T213预报性能的影响

采用云变量自由变化的方案，在国家气象中心全球业务模式T213L31的初始场中增加有关云变量的信息，通过2005年6—8月和2015年12月—2006年2月各3个月的连续滚动对比试验的统计分析和个例预报分析，研究探讨了全球模式初值中增加云变量对模式预报性能的影响。初步研究结果表明:采用自由变化的方案在初值场中增加云的信息，使模式能够较为合理地描述出模式预报初期与云相关变量分布和变化特征，降低了spin-up现象对模式前期降水预报能力的影响，同时对500 hPa形势场预报也有一定程度提高。     

一次飑线过程的雷达回波分析与数值模拟

2003年4月12日, 一条飑线袭击了江西、福建、浙江三省, 所到之处出现冰雹、大风等强烈天气, 这次过程强度强, 影响范围大, 三省交界及附近区域有二十多个测站出现冰雹、大风, 冰雹直径有的达3 cm以上, 最大风速达32 m/s。该文利用建阳新一代天气雷达探测到的回波以及中尺度非静力数值模式 (MM5) 对这次过程进行数值模拟, 分析此次强对流过程。结果表明:雷达回波显示出飑线的带状强回波, 线状回波上呈现波型特征; 在数值模拟结果中看到在系统发生的带状区域内有多个中尺度涡旋存在, 在飑线内有中尺度涡旋簇和弓形回波。     

深圳LAP-3000型风廓线雷达系统及应用

介绍风廓线雷达的历史、LAP-3000型风廓线雷达的基本原理以及深圳市LAP-3000型风廓线雷达的数据存贮格式、风廓线雷达产品的显示等内容;并给出了几种典型风场在风廓线上的反映及对一次冷空气过程的分析。     

Ages and metallicities of five intermediate-age star clusters projected towards the Small Magellanic Cloud

Colour–magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected on to the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system C and T ₁ filters, allowing the determination of ages by means of the magnitude difference between the red giant clump and the main-sequence turn-off, and metallicities from the red giant branch locus. The clusters have ages in the range 2–6 Gyr , and metallicities in the range −1.65<[Fe/H]<−1.10, increasing the sample of intermediate-age clusters in the SMC. L116, the outermost cluster projected on to the SMC, is a foreground cluster, and somewhat closer to us than the Large Magellanic Cloud. Our results, combined with those for other clusters in the literature, show epochs of sudden chemical enrichment in the age–metallicity plane, which favour a bursting star formation history as opposed to a continuous one for the SMC.