Developing interactive geospatial holograms for spatial decision-making

Spatial decision-making in time-critical situations requires effective and usable two-dimensional and three-dimensional (3D) cartographic products. Holographic displays allow decision makers to work with auto-stereoscopic maps without the hassle of interacting with complex user interfaces or additional vision hardware. Holographic production processes have advanced greatly in a short period and now support timely and full integration of digital 3D models in geospatial holograms. George Mason University’s and Zebra Imaging’s research on interactive holographic motion displays showcases the leadership in moving cartography and geovisualization research in the US forward. In close cooperation with academic researchers, decision makers, and domain experts, the usability and usefulness of these cartographic products is tested and design guidelines for effective geospatial holograms are being developed.     

Advancing isotope-enabled hydrological modelling for ungauged calibration of data-scarce humid tropical catchments

Realistic projections of the future climate and how this translates to water availability is crucial for sustainable water resource management. However, data availability constrains the capacity to simulate streamflow and corresponding hydrological processes. Developing more robust hydrological models and methods that can circumvent the need for large amounts of hydro-climatic data is crucial to support water-related decisions, particularly in developing countries. In this study, we use natural isotope tracers in addition to hydro-climate data within a newly developed version of the spatially-distributed J2000iso as an isotope-enabled rainfall-runoff model simulating both water and stable isotope (δ²H) fluxes. We pilot the model for the humid tropical San Carlos catchment (2500 km²) in northeastern Costa Rica, which has limited time series, but spatially distributed data. The added benefit of simulating stable isotopes was assessed by comparing different amounts of observation data using three model calibration strategies (i) three streamflow gauges, (ii) three gauges with stream isotopes and (iii) isotopes only. The J2000iso achieved a streamflow Kling–Gupta efficiency (KGE) of 0.55–0.70 across all the models and gauges, but differences in hydrological process simulations emerged when including stable water isotopes in the rainfall-runoff calibration. Hydrological process simulation varied between the standard J2000 rainfall-runoff model with a high simulated surface runoff proportion of 37% as opposed to the isotope version with 84%–89% simulated baseflow or interflow. The model solutions that used only isotope data for calibration exhibited differences in simulated interflow, baseflow and model performance but captured bulk water balances with a reasonable match between the simulated and observed hydrographs. We conclude that J2000iso has shown the potential to support water balance modelling for ungauged catchments using stable isotope, satellite and global reanalysis data sets.     

Perovskite U–Pb ages and the Pb isotopic composition of alkaline volcanism initiating the Permo-Carboniferous Oslo Rift

The Permo-Carboniferous Oslo Rift developed in the foreland of the Variscan orogen over a period of some 50 million years through a process characterized by moderate extension and widespread magmatism. The overall tectonic situation places the Oslo Rift in a post-collisional, dextral transtensional setting related to the convergence between Baltica, Laurentia, Gondwana and Siberia during assembly of Pangea, the location probably reflecting the control by pre-existing lithospheric structures. Although a detailed understanding of these factors and processes relies strongly on having a good age control, the dating of mafic to ultramafic alkalic volcanic units formed during initial rifting has been a very challenging task. In this study we have successfully employed perovskite from melilitic and nephelinitic volcanic rocks, together with magmatic titanite in a more evolved ignimbrite, to obtain ID-TIMS high-precision U–Pb ages. Three samples from various levels of the Brunlanes succession, in the southernmost exposures of the Oslo Graben, yield ages of 300.2 ± 0.9, 300.4 ± 0.7 and 299.9 ± 0.9 Ma. A melililitic tuff at the base of the Skien succession further to the northwest yields a slightly younger age of 298.9 ± 0.7 Ma. The initial Pb compositions derived mainly from coexisting pyroxene, apatite and hornblende are characterized by extremely radiogenic initial ²⁰⁶Pb/²⁰⁴Pb ratios (up to 21.3) that confirm a provenance of these early alkaline basalts from HIMU-type sources. The U–Pb ages coincide with the Gzhelian age inferred from fossils in the upper part of the basal rift sedimentary fill of the Asker Group, and post-date the underlying basal sedimentary sequences by some 10 million years, pointing to a relatively rapid initiation of the rifting process.     

Spatial variability of diatom assemblages in surface lake sediments and its implications for transfer functions

The variability of diatom species composition in lake surface sediments was studied along transects in four lakes in northeastern Germany. Three dimictic lakes (Dudinghausener See, Tiefer See, and Cambser See) and one shallow lake (Groß Peetscher See) were sampled. Large differences in diatom composition were found between adjoined samples from different depths within one lake. These differences were mainly displayed by planktonic species. For example, the relative frequency of Stephanodiscus alpinus varied between 4% and 43% within the surface sediment samples of the open-water region of Dudinghausener See. Using transfer functions for total phosphorus (TP) based on the European Diatom data-base (EDDI) combined TP data-set and a local data-set, the inferred TP values differed strongly within one lake when using Weighted Averaging-Partial Least Squares (WA-PLS) regression. In Tiefer See (average of measured TP: 30 μg l^?1), the inferred TP values range from 45 to 110 μg l^?1 using the transfer function based on WA-PLS regression and the EDDI data-set; and from 16 to 100 μg l^?1 using WA-PLS and a local data-set. Performing Maximum Likelihood (ML) regression reduced the difference between measured and inferred values. For Tiefer See, the inferred TP values range between 16 and 45 μg l^?1 using ML regression and the local data-set. Therefore, it seems that ML regression can deal better with the natural variability in species composition than WA-PLS regression. In general, it was shown that by using ML regression and the local data-set, the error of the inferred values was significant lower for all lakes than using WA-PLS regression and the EDDI data-set. The Root Mean Square Error of Prediction (RMSEP) was not useful in selecting the most stable transfer function.     

Air pumping for alleviation of heavy smog in Beijing

Beijing often suffers under heavy smog.During such events which occur mostly in autumn and winter,people are desperate for fresh air.The formation of heavy smog is due to foremost human induced air pollution,but geographic and meteorological conditions,especially below a surface inversion,play an important role.We propose to destroy the inversion by pumping air from above the inversion layer to the surface layer to alleviate the severity of the smog.While long-term air quality improvement depends on the reduction of air pollution emission,air pumping may provide relief in the interim for the Beijing citizens.We estimate that an air pumping at a rate 2×10~7m~3s~(–1)can lead to significantly improved air quality in Beijing,due to(1)direct clean air input;(2)increased instability and vertical mixing and(3)a positive radiation-mixing feedback.The pumping requires an energy input of 10 GW,comparable with the energy consumption in Beijing for air conditioning in summer.We propose to use wind energy from Inner Mongolia for the pumping,which has currently an installed wind energy capacity of 70GW.     

Metamorphism, isotopic ages and composition of lower crustal granulite xenoliths from the Cretaceous Salta Rift, Argentina

Crustal xenoliths from basanitic dikes and necks that intruded into continental sediments of the Cretaceous Salta Rift at Quebrada de Las Conchas, Provincia Salta, Argentina were investigated to get information about the age and the chemical composition of the lower crust. Most of the xenoliths have a granitoid composition with quartz-plagioclase-garnet-rutile ± K-feldspar as major minerals. The exceedingly rare mafic xenoliths consist of plagioclase-clinopyroxene-garnet ± hornblende. All xenoliths show a well equilibrated granoblastic fabric and the minerals are compositionally unzoned. Thermobarometric calculations indicate equilibration of the mafic xenoliths in the granulite facies at temperatures of ca. 900 °C and pressures of ca. 10 kbar. The Sm-Nd mineral isochron ages are 95.1 ± 10.4 Ma, 91.5 ± 13.0 Ma, 89.0 ± 4.2 Ma (granitoid xenoliths), and 110.7 ± 23.6 Ma (mafic xenolith). These ages are in agreement with the age of basanitic volcanism (ca. 130–100 and 80–75 Ma) and are interpreted as minimum ages of metamorphism. Lower crustal temperature at the time given by the isochrons was above the closure temperature of the Sm-Nd system (>600–700 °C). The Sm-Nd and Rb-Sr isotopic signatures (¹⁴⁷Sm/¹⁴⁴Nd = 0.1225–0.1608; ¹⁴³Nd/¹⁴⁴Nd_{t 0} = 0.512000–0.512324; ⁸⁷Rb/⁸⁶Sr = 0.099–0.172; ⁸⁷Sr/⁸⁶Sr_{t 0} = 0.708188–0.7143161) and common lead isotopic signatures (²⁰⁶Pb/²⁰⁴Pb = 18.43–18.48; ²⁰⁷Pb/²⁰⁴Pb = 15.62–15.70; ²⁰⁸Pb/²⁰⁴Pb = 38.22 –38.97) of the granitoid xenoliths are indistinguishable from the isotopic composition of the Early Paleozoic metamorphic basement from NW Argentina, apart from the lower ²⁰⁸Pb/²⁰⁴Pb ratio of the basement. The Sm-Nd depleted mantle model ages of ca. 1.8 Ga from granitoid xenoliths and Early Paleozoic basement point to a similar Proterozoic protolith. Time constraints, the well equilibrated granulite fabric, P-T conditions and lack of chemical zoning of minerals point to a high temperature in a crust of nearly normal thickness at ca. 90 Ma and to a prominent thermal anomaly in the lithosphere. The composition of the xenoliths is similar to the composition of the Early Paleozoic basement in the Andes of NW Argentina and northern Chile. A thick mafic lower crust seems unlikely considering low abundance of mafic xenoliths and the predominance of granitoid xenoliths. Received: 21 July 1998 / Accepted: 27 October 1998     

Recolonisation by Macrobenthos Mobilises Organic Phosphorus from Reoxidised Baltic Sea Sediments

In recent decades, eutrophication has increased the extent of hypoxic and anoxic conditions in many coastal marine environments. In such conditions, the nutrient flux across the sediment?Cwater interface is a key process controlling the biogeochemical dynamics, and thereby the level and character of biological production. In some areas, management attempts to drive the ecosystem towards phosphorus (P) limitation, which calls for reliable knowledge on the mechanisms controlling P-cycling. We report a well-controlled laboratory experiment on benthic fluxes of P, when shifting from a state of hypoxic and azoic sediments to oxic and zoic bottom conditions. Adding any of three types of macrobenthic fauna (mysid shrimp, pontoporeid amphipod and tellinid clam) to oxygenated aquarium sections resulted in benthic P fluxes that differed consistently from the azoic control sections. All species caused liberation of dissolved organically bound P (DOP) from the sediment, in contrast to the azoic systems. The shrimp and the amphipod also resuspended the sediment, which resulted in a release of P bound to particles (>0.45???m). Dissolved inorganic phosphate (DIP) was released during hypoxic conditions, but was taken up after oxygenation, irrespective of the presence or absence of bottom fauna. In the presence of fauna, the uptake of DIP roughly equalled the release of DOP, suggesting that the benthic efflux of DOP following oxygenation and bottom fauna (re)colonisation might be considerable. This is an hitherto overlooked animal-controlled nutrient flux, which is missing from coastal marine P budgets.     

High-temperature neutron diffraction study of deuterated brucite

To study the structural behavior of brucite at high temperature, we conducted in situ neutron diffraction experiments of a deuterated brucite powder sample, Mg(OD)₂, in the temperature range 313–583 K. The sample was stable up to 553 K, above which it started to decompose into periclase (MgO) and D₂O vapor. Rietveld analyses of the obtained data were performed using both single-site and three-site split-atom hydrogen models. Our results show that with increasing temperature, unit-cell parameter c increases at a rate ~7.7 times more rapidly than a. This large anisotropy of thermal expansion is primarily due to rapid increase in the interlayer thickness along the c-axis on heating. The amplitudes of thermal vibration for Mg, O, and D increase linearly with increasing temperature; however, the rate of the increase for the lighter D is much larger. In addition, D vibrates anisotropically with a higher magnitude within the (001) plane, as confirmed by our first-principles phonon calculations. On heating, the interatomic distances between a given D and its associated O and D from the adjacent [MgO₆] layer increase, whereas the O–D bond length decreases. This behavior suggests weakened D···O and D···D interlayer interactions but strengthened O–D bonding with increasing temperature.     

Danish Regional Development During Economic Crisis

Illeris, Sven: Danish Regional Development During Economic Crisis. Geografisk Tidsskrift 84: 53–62. Copenhagen, January 1984.

The paper deals with the distribution of population and economic activities during the 1980–83 economic crisis. The decentralisation of the 1970's was weakened, but there was no return to the concentration of former decades. Important reasons seem to be the decline in house-building, and the structural developments (in 1980 crisis in the primary and secondary sectors which are over-represented in peripheral regions and small settlements).