Atmospheric turbulence theory applied to GPS carrier-phase data

Turbulent irregularities in the lower atmosphere cause physical correlations between Global Positioning System (GPS) carrier-phase measurements. Based on turbulence theory, a variance–covariance model is developed in this paper that reflects these correlations. The main result shows that the obtained fully-populated variance–covariance matrices depend not only on the satellite-station geometry, but also on the prevailing atmospheric conditions, which are parameterised by, e.g., the von Karman spectrum of refractivity fluctuations and the wind velocity vector. It is shown that the amount of the correlation between two GPS carrier-phase observations is inversely related to the separation distance of the corresponding ray paths through the turbulent atmosphere. Furthermore, the wind velocity and direction play a key role in the correlation.     

Lost in translation? Standardising the terminology used in marine invasion biology and updating South African alien species lists

Confusion between terms and ambiguities among definitions have long plagued the field of invasion biology. One result is disruption in flow of information from researchers to policy-makers and managers who rely on science to inform regulatory frameworks and management actions. We reviewed the South African marine biology literature to quantify the current usage of terminology describing marine invasions and found a variety of terms in use, few of which are defined when used. In response, we propose standard terminology that aligns with international practice. We then interpreted the Blackburn unified framework for biological invasions within the marine context and used this as a transparent way to apply the standardised terms to an updated list of marine alien species for the country. This resulted in the recognition of 36 alien and 53 invasive species within South Africa. Most notably, follow-up research is required to confirm the status of at least 11 listed species, the majority of which have been recorded only once, or not in the past 25 years. It is hoped that by standardising terminology, marine science in South Africa will better support authorities charged with managing the threat posed by marine alien species.     

Lagrangian Particle Dispersion Models in the Grey Zone of Turbulence: Adaptations to FLEXPART-COSMO for Simulations at 1 km Grid Resolution

Boundary-Layer Meteorology - Lagrangian particle dispersion models (LPDMs) are frequently used for regional-scale inversions of greenhouse gas emissions. However, the turbulence parameterizations...     

Field assessment of surface water–groundwater connectivity in a semi‐arid river basin (Murray–Darling,Australia)

In semi‐arid and arid river basins, understanding the connectivity between rivers and alluvial aquifers is one of the key challenges for the management of groundwater resources. The type of connection present (gaining, losing‐connected, transitional and losing‐disconnected) was assessed at 12 sites along six Murray–Darling Basin river reaches. The assessments were made by measuring the hydraulic head in the riparian zone near the rivers to evaluate if the water tables intersected the riverbeds and by measuring fluid pressure (ψ) in the riverbeds. The rationale for the latter was that ψ will always be greater than or equal to zero under connected conditions (either losing or gaining) and always lesser than or equal to zero under losing‐disconnected conditions. A mixture of losing‐disconnected, losing‐connected and gaining conditions was found among the 12 sites. The losing‐disconnected sites all had a riverbed with a lower hydraulic conductivity than the underlying aquifer, usually in the form of a silty clay or clay unit 0.5–2 m in thickness. The riparian water tables were 6 to 25 m below riverbed level at the losing‐disconnected sites but never lower than 1 m below riverbed level at the losing‐connected ones. The contrast in water table depth between connected and disconnected sites was attributed to the conditions at the time of the study, when a severe regional drought had generated a widespread decline in regional water tables. This decline was apparently compensated near losing‐connected rivers by increased infiltration rates, while the decline could not be compensated at the losing‐disconnected rivers because the infiltration rates were already maximal there. Copyright © 2012 John Wiley & Sons, Ltd.     

Spatial patterns and environmental drivers of benthic infaunal community structure and ecosystem function on the New Zealand continental margin

To investigate regional drivers of spatial patterns in macro- and meio-faunal community structure (abundance, biomass and taxonomic diversity) and ecosystem function (sediment community oxygen consumption [SCOC]), we sampled two regions in close proximity on New Zealand's continental margin—the Chatham Rise and the Challenger Plateau. Sites (n = 15) were selected in water depths ranging from 266–1212 m to generate a gradient in sedimentary properties and, in particular, surface pelagic productivity. Both macro- and meio-fauna abundance and biomass was 2–3.5 times higher on the Chatham Rise than on the Challenger Plateau, reflecting regional differences in pelagic primary production. We also found significant inter- and intra-regional differences in macro-fauna taxonomic diversity with two distinctive site groupings in each region. Univariate and multivariate measures of macro-fauna community attributes were most strongly correlated with sediment photosynthetic pigment (explaining 24%–59% of the variation). Sediment pigment content was as equally important in explaining meio-fauna community structure (36%–7%). Unlike community structure, SCOC was most strongly correlated with depth (44%), most likely reflecting temperature effects on benthic metabolism. Our results highlight the importance of a benthic labile food supply in structuring infaunal communities on continental margins and emphasise a tight coupling between pelagic and benthic habitats.     

STATE POLICY AND URBAN SYSTEMS :THE CASE OF CHINA

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How can remote sensing contribute in groundwater modeling?

Groundwater resources assessment, modeling and management are hampered considerably by a lack of data, especially in semi-arid and arid environments with a weak observation infrastructure. Usually, only a limited number of point measurements are available, while groundwater models need spatial and temporal distributions of input and calibration data. If such data are not available, models cannot play their proper role in decision support as they are notoriously underdetermined and uncertain. Recent developments in remote sensing have opened new sources for distributed spatial data. As the relevant entities such as water fluxes, heads or transmissivities cannot be observed directly by remote sensing, ways have to be found to link the observable quantities to input data required by the model. An overview of the possibilities for employing remote-sensing observations in groundwater modeling is given, supported by examples in Botswana and China. The main possibilities are: (1) use of remote-sensing data to create some of the spatially distributed input parameter sets for a model, and (2) constraining of models during calibration by spatially distributed data derived from remote sensing. In both, models can be improved conceptually and quantitatively.     

大兴安岭中生代花岗岩类的地球化学

大兴安岭中生代花岗岩根据微量元素地球化学特征划分为高锶花岗岩类和低锶花岗岩类，前者富集Ba、Sr、Ti，而后者强烈亏损这些元素而富集大离子亲石元素和高场强元素。高锶花岗岩类主要由石英闪长岩、英云闪长岩和花岗闪长岩组成，属于Ⅰ型花岗岩；低锶花岗岩类由二长花岗岩、正长花岗岩、碱长花岗岩和碱性花岗岩组成，二长花岗岩一正长花岗岩一碱长花岗岩也属于Ⅰ型花岗岩，碱性花岗岩为A1型花岗岩。这两类花岗岩均显示εNd(t)正值^87Sr／^86Sr低值以及较低的Nd模式年龄。高锶与低锶花岗岩类地球化学差异性表明，高锶花岗岩起源于相对亏损的幔源岩浆的分异作用，而低锶花岗岩类的源区与显生宙地壳增生时期起源于地幔的年轻地壳物质有关，即起源于富集型幔源基性岩石的部分熔融。大兴安岭中生代花岗岩与流纹岩之间地球化学相似性以及与玄武岩类的相关性表明，它们是统一的构造一岩浆体系的产物，共同制约于古亚洲洋闭合后的大陆伸展的构造环境和闭合期间壳幔相互作用形成的地幔源区。     

南菲律宾地区类埃达克岩和富铌玄武质熔岩的成因

埃达克岩（adakite)最初 是指由消减板片玄武岩物质熔融形成的富硅、富钠、高Sr/Y和La/Yb比值的弧火山熔岩。它通常产在会聚带，这个部位的年轻的、因而仍然是热的大洋板片正在发生俯冲消减。富铌的岛弦玄武央进则是吕等到高碱的镁铁质熔岩，它们相对于正常的岛弦玄武岩含有较多的高场强元素（HFSE）。这些玄武岩通常与埃达克央共生， 这一组合是直被用于论证他们的高HFSE含量是因为他们的地幔源区受到板片来源的熔体的交代。先前的区域研究结果表明，南菲律宾是埃达克岩和富铌岛孤玄武岩的一个典型产地。然而最近的详细研究显示，尽管该地区的一些岛弧火山岩是类埃达克岩的，但是它们很可能是来自地幔楔的母岩浆的分异作用的产物，而这里的地幔楔主要是受沉积来源的成分交代的，此外，菲律宾南部最典型的富铌熔岩中HFSE的富集，也很有可能是起因于似乎是西太平洋边缘特有的富集地幔组分的熔融。这些结果提出了如下问题：南菲律宾是否存在真正的板片来源的熔体？这里的富铌岛弧 熔岩是否起因于地幔楔被这种熔体交代？     

Sequence of the Cenozoic Mammalian Faunas of the Linxia Basin in Gansu, China

In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pl