Plant drought tolerance trait is the key parameter in improving the modeling of terrestrial transpiration in arid and semi-arid regions

陆面过程蒸腾作用的模拟制约着天气,气候降水预测的精确度.近几十年来,为了更好地描述植被蒸腾的水力约束,陆面过程模式发展了基于植物性状的植物水力胁迫方案.然而,我们对于植物性状在蒸腾模拟中的地位仍然缺乏了解,植物性状对蒸腾的重要性仍需进一步量化.本研究利用Morris方法评估植物性状参数在通用陆面模式植物水力胁迫方案(CoLM-P₅₀HS)中的重要性,针对17种植物性状,筛选出最为重要的:耐旱性状(P₅₀),气孔性状,和光合作用性状.在12个FLUXNET站点中,参数的重要性由归一化敏感度来衡量.P₅₀的重要性随着降水的减少而增加,而气孔性状和光合作用性状的重要性则随着降水的减少而减少.在干旱或半干旱地区,P₅₀比气孔性状和光合作用性状更重要,这意味着当植物经常经历干旱时,水力安全策略比植物生长策略更关键.而耐旱性状的巨大变异性进一步暗示了多种植物水力安全策略的共存.忽视P₅₀的变异性可能会对陆面过程模式蒸腾作用的模拟造成严重误差.因此,为了更好地表示植物水力功能的变异性,需要增加对耐旱性状的观测并耦合到陆面模式中.     

水生态屏障适宜宽度界定研究进展

在总结水生态屏障研究历程的基础上,对水生态屏障的概念进行了探讨,提出了水生态屏障的定义。从河流、湖泊、水库3种主要水生态屏障类型说明水生态屏障的主要功能及适宜宽度研究进展,并从生态学、水文学、地理学、遥感学的技术应用评述了水生态屏障宽度的界定方法。目前,对水生态屏障适宜宽度的标准还缺乏统一的认识,流域尺度下水库生态屏障适宜宽度的界定是水生态屏障宽度界定面临的难点问题,提出综合水文学、生态学、环境科学及地形、遥感、地理信息等多学科理论及技术手段构建流域尺度的生态水文模型是界定水生态屏障及其水库生态屏障适宜宽度的有效方法。     

陕南镇坪地区黑色岩系含矿性及找矿潜力分析

黑色岩系是构成许多重要矿床的赋矿岩系,与它有关的有用元素和组份,呈自然金属、硫化物、氧化物、碳酸盐、硫酸盐、磷酸盐等形式产出。陕南镇坪地区下寒武统鲁家坪组黑色岩系具有较好的含矿性及成矿地质条件,找矿潜力大。     

保定—沧州地区土壤地球化学公里网格样方代表性研究

土壤中的元素在空间上的分布具有一定变异性。在开展土壤地质环境调查监测时,有必要进行单点采样的科学性分析。对于在1 km2的区域内,如何实现科学、有效和合理地采样来获得区域内土壤元素含量的空间分布特征是一个需要解决的课题。本文在保定—沧州平原地区,选择36个县市,在每个县市的大片农田区以十字形方式采集9个单点样,通过不同的样品组合方式,来研究其结果之间的差别。结果显示:不同的混合方式,元素浓度含量的相对偏差大部分小于15%,在可接受的误差范围内。因此在1 km2区域的中心采集一个单点样,即可基本代表该区域内土壤元素的含量组成。     

Molar‐Tooth Structure from the Mesoproterozoic Wumishan Formation in Lingyuan,Yanshan Region,North China,and Geological Implications

Although its origin has not yet reached a consensus so far, MTS (Molar-Tooth Structure) has been documented for more than 100 years. Current study reports a discovery of MTS from the Mesoproterozoic Wumishan Formation, Lingyuan, Yanshan Region, North China, and the features and geological implications of MTS are further discussed. Here, straitigraphic horizons of MTS’s occurrences show that it was mainly located within the top part of the Wumishan Formation, i.e., limestone unit. Four kinds of morphology of MTS, i.e., fine fusiform, debris, ribbon, ptigmatic and nodular (irregular), were recognized and thought to be highly related to the sedimentary environments and facies. Geochemistry of MTS including oxides, trace elements and C, O and Sr isotopes indicates that the horizons of MTS-bearing is of higher Sr/Ba and Ca/Mg ratios, lower positive δ13C and highly negative δ18O values than the adjacent stratigraphic levels of rare MTS. Lithology, morphology and geochemistry of MTS in the Wumishan Formation suggest that MTS occurs mainly in shallow subtidal near the storm wave base, which is typically characterized by warm temperature, oversaturated calcium carbonate seawater and high organic productivity. Furthermore, occasional enrichment of algae bacteria here is more favorable for the calcification of calcium oozes and catalytic for MTS. C isotope composition of the Wumishan Formation and MTS of this study is well correlated with that of the Mesoproterozoic Belt Supergroup, North America and Riphean, Siberia, suggesting that MTS acts as a sedimentary record responding to global changes and is a perfect indicator in Precambrian stratigraphic correlation worldwide.     

Stratigraphy and Geochronology of Vertebrate Fossil‐Bearing Jurassic Strata from Linglongta,Jianchang County,Western Liaoning,Northeastern China

Northeastern China contains widely distributed Jurassic terrestrial strata that have yielded many spectacular mammal and pterosaur fossils, in addition to feathered dinosaur fossils and more recent discoveries from Jianchang, particularly from western Liaoning. However, the fossil-bearing stratigraphic succession, regional correlation, and age estimates of the fossils found in Jianchang County and nearby areas have been contentious. Here, we report on the vertebrate fossil-bearing Jurassic stratigraphy from Linglongta, Jianchang County, western Liaoning, including a SHRIMP U-Pb zircon date unambiguously associated with the fossil horizons. The primary goal was to determine the vertebrate fossil-bearing succession. A further aim was to provide age estimations for the fossil-bearing horizon as well as the earliest appearance of feathered dinosaurs, the eutherian–placental clade, and transitional pterosaurs. Field investigations showed that the vertebrate fossil-bearing stratigraphic succession in Jianchang County mainly consists of basal andesites overlain by rhythmic tuffs and tuffaceous lacustrine sediments, with the upper intermediate or acidic lavas interbedded with laminated more or less tuffaceous lacustrine deposits. This sequence correlates well with the Middle Jurassic Lanqi/Tiaojishan Formation in northeastern China. Detailed and accurate field observations showed that the well-preserved vertebrate fossils were buried in either the middle or the upper fine-grained laminated lacustrine deposits. Previous and current SHRIMP U-Pb zircon dates provide an age estimation of 161–159 Myr for the fossil-bearing horizon and vertebrates. This indicates that the earliest appearance of feathered dinosaurs here was more than 159 Myr ago and unquestionably older than Archaeopteryx from Germany, making these the earliest known feathered dinosaurs in the world. Furthermore, the eutherian–placental clade and the known transitional pterosaurs first emerged no later than 161 Myr. The vertebrate assemblage unearthed recently from Linglongta and neighboring areas in Jianchang County belongs to the Daohugou Biota. In addition to feathered dinosaurs, this biota was characterized by mammals, primitive pterosaurs, insects, and plants and was present in Inner Mongolia, western Liaoning, and northern Hebei in northeastern China during the Middle–Late Jurassic.     

冀西北尚义上侏罗统—下白垩统后城组恐龙足迹新发现及生物古地理意义*

简要报道了新近首次在冀西北张家口尚义地区发现的恐龙足迹。野外地质调查发现,恐龙足迹赋存于尚义晚中生代盆地侏罗系—白垩系后城组顶部。恐龙行迹呈近东西向展布,由数十个足迹构成。初步研究表明,造迹者分别属于兽脚类和蜥脚类恐龙,由西向东行进。足迹中包括兽脚类足迹70余个,组成数个行迹;蜥脚类足迹15个,构成1列行迹。蜥脚类足迹特征显示其可能属于游泳状的行迹。华北北部土城子组/后城组发育于燕辽生物群—热河生物群更替演化时期（晚侏罗世—早白垩世早期）,以往在该时期沉积物中罕见脊椎动物骨骼化石。近年来华北北部土城子组/后城组中频繁发现的恐龙足迹表明,燕辽生物群—热河生物群更替演化时期发育着以恐龙为代表的脊椎动物群。该发现将有助于进一步了解土城子组/后城组沉积时期恐龙属种的多样性及其生物古地理环境。晚侏罗世—早白垩世早期沉积古地理和古生态环境及其与恐龙动物群发育的研究有助于揭示陆地生物群更替演化和环境的关系。     

Effects of heavy metals on the performance of anaerobic sulfidogenic reactor using rape straw as carbon source

Effects of Zn²⁺, Cu²⁺ and Cd²⁺ in the synthetic acid mine drainage on the performance of the anaerobic sulfidogenic reactor using rape straw as carbon source were explored. Two different cases were respectively observed for the different metal dosages: stimulatory at lower concentrations and toxic/inhibitory at higher concentrations. Cellulose and hemicellulose were the major components hydrolyzed in the rape straw. Analysis of the heavy metals distribution in the anaerobic digested solid residue showed that adsorption and precipitation were the major mechanisms for the removal of heavy metals. This was also confirmed by the results of scanning electron microscopy and energy-dispersive spectrometry analysis.     

LIDAR点云滤波算法分析——以ISPRS测试实验为参考

在分析ISPRS测试实验的基础上,研究机载LIDAR点云数据滤波算法的特性,将算法分成4类进行介绍,总结经典算法的定量分析性能,为后续的研究提供一个参考,并展望滤波算法改进和发展的方向.     

基于分布式GIS的工程移民管理系统设计与实现

针对工程移民管理信息化建设的现状,提出以基于GIS的分布式处理技术为指导,采用.Net分层架构技术构建工程移民管理系统。阐述基于抽象工厂的分层架构体系,以解决数据库变更导致系统不兼容的问题;设计多级树模型,以解决移民实物指标动态管理的问题;重点探讨采用分布式空间数据库技术实现海量时空数据的高效存储管理,从而便于完成复杂...