Finding a Way: Modeling Landscape Prerequisites for Roman and Early‐Medieval Routes in the Netherlands     

Rowin J. van Lanen  Menne C. Kosian  Bert J. Groenewoudt  Esther Jansma 《Geoarchaeology》2015,30(3):200-222

This study focuses on reconstructing landscape prerequisites for Roman and early‐medieval routes in the Netherlands. We applied spatial modeling to modern and paleogeographical landscape data in order to determine geographical obstacles for possible translocation in ca. A.D. 100 and 800 via land and water. Network‐friction values were calculated to produce a spatial model of possible movement corridors and to enable the integration of archaeological data. Results show that in geographically dynamic lowland regions such as the current Netherlands, landscape units such as water, peat, and levees must have had a high impact on route orientation. The lower parts of the western Netherlands were almost inaccessible by land, implying that its inhabitants largely must have depended on rivers and streams for transportation. In Dutch coastal and river areas, the landscape changed drastically between A.D. 100 and 800, the largest changes occurring along the coast.  相似文献   

Pollen‐based biome reconstructions for Colombia at 3000, 6000, 9000, 12 000, 15 000 and 18 000 14C yr ago: Late Quaternary tropical vegetation dynamics     

Robert Marchant  Hermann Behling  Juan‐Carlos Berrio  Antoine Cleef  Joost Duivenvoorden  Henry Hooghiemstra  Peter Kuhry  Bert Melief  Elisabeth Schreve‐Brinkman  Bas Van Geel  Thomas Van der Hammen  Guido Van Reenen  Michael Wille 《第四纪科学杂志》2002,17(2):113-129

Colombian biomes are reconstructed at 45 sites from the modern period extending to the Last Glacial Maximum (LGM). The basis for our reconstruction is pollen data assigned to plant functional types and biomes at six 3000‐yr intervals. A reconstruction of modern biomes is used to check the treatment of the modern pollen data set against a map of potential vegetation. This allows the biomes reconstructed at past periods to be assessed relative to the modern situation. This process also provides a check on the a priori assignment of pollen taxa to plant functional types and biomes. For the majority of the sites, the pollen data accurately reflect the potential vegetation, even though much of the original vegetation has been transformed by agricultural practices. At 18 000 ¹⁴C yr BP, a generally cool and dry environment is reflected in biome, assignments of cold mixed forests, cool evergreen forests and cool grassland–shrub; the latter extending to lower altitudes than presently recorded. This signal is strongly recorded at 15 000 and 12 000 ¹⁴C yr BP, the vegetation at these times also reflecting a relatively cool and dry environment. At 9000 ¹⁴C yr BP there is a shift to biomes thought to result from slightly cooler environmental conditions. This trend is reversed by 6000 ¹⁴C yr BP; most sites, within a range of different environmental settings, recording a shift to more xeric biome types. There is an expansion of steppe and cool mixed‐forest biomes, replacing tropical dry forest and cool grassland–shrub biomes, respectively. These changes in biome assignments from the modern situation can be interpreted as a biotic response to mid‐Holocene climatic aridity. At 3000 ¹⁴C yr BP the shift is mainly to biomes characteristic of slightly more mesic environmental conditions. There are a number of sites that do not change biome assignment relative to the modern reconstruction, although the affinities that these sites have to a specific biome do change. These ‘anomalies’ are interpreted on a site‐by‐site basis. Spatially constant, but differential response of the vegetation to climatic shifts are related to changes in moisture sources and the importance of edaphic controls on the vegetation. The Late Quaternary reconstruction of large‐scale vegetation dynamics in Colombia allows an understanding of the environmental controls on these to be developed. In particular, shifts in the character of the main climatic systems that influence Colombian vegetation are described. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Exploring the hydrological effects of normal faults at the boundary of the Roer Valley Graben in Belgium using a catchment-scale groundwater flow model     

Casillas-Trasvina  Alberto  Rogiers  Bart  Beerten  Koen  Wouters  Laurent  Walraevens  Kristine 《Hydrogeology Journal》2022,30(1):133-149

Hydrogeology Journal - Faults may impact regional groundwater flow and transport, so it is important to include them during aquifer-system conceptualization and while constructing groundwater flow...  相似文献   

In memory of Charles David Keeling     

Pieter  Tans Bert  Bolin 《Tellus. Series B, Chemical and physical meteorology》2006,58(5):329-330

  相似文献   

Flow of Canadian basin deep water in the Western Eurasian Basin of the Arctic Ocean     

Göran Björk  Leif G. Anderson  Martin Jakobsson  Dennis Antony  Björn Eriksson  Patrick B. Eriksson  Benjamin Hell  Sofia Hjalmarsson  Timothy Janzen  Sara Jutterström  Johanna Linders  Ludvig Löwemark  Christian Marcussen  K. Anders Olsson  Bert Rudels  Emma Sellén  Morten Sølvsten 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(4):577-586

The LOMROG 2007 expedition targeted the previously unexplored southern part of the Lomonosov Ridge north of Greenland together with a section from the Morris Jesup Rise to Gakkel Ridge. The oceanographic data show that Canadian Basin Deep Water (CBDW) passes the Lomonosov Ridge in the area of the Intra Basin close to the North Pole and then continues along the ridge towards Greenland and further along its northernmost continental slope. The CBDW is clearly evident as a salinity maximum and oxygen minimum at a depth of about 2000 m. The cross-slope sections at the Amundsen Basin side of the Lomonosov Ridge and further south at the Morris Jesup Rise show a sharp frontal structure higher up in the water column between Makarov Basin water and Amundsen Basin water. The frontal structure continues upward into the Atlantic Water up to a depth of about 300 m. The observed water mass division at levels well above the ridge crest indicates a strong topographic steering of the flow and that different water masses tend to pass the ridge guided by ridge-crossing isobaths at local topographic heights and depressions. A rough scaling analysis shows that the extremely steep and sharply turning bathymetry of the Morris Jesup Rise may force the boundary current to separate and generate deep eddies.  相似文献   

Are flatfish nursery grounds richer in benthic prey?     

Nomie Wouters  Henrique N. Cabral 《Estuarine, Coastal and Shelf Science》2009,83(4):613-620

The density of macrobenthos was evaluated in the nursery grounds for flatfish of six estuarine systems along the coast of Portugal by comparison with adjacent non-nursery areas. The dry weight and density of macrobenthic fauna were significantly higher in the nursery grounds. Polychaeta, Bivalvia, Oligochaeta and Isopoda were found to be significantly more abundant in the nursery than in the non-nursery grounds. For Isopoda and Bivalvia, total dry weight was also significantly higher in the nursery areas. Correspondence analysis based on density showed that the nursery areas of the different estuaries grouped together relative to non-nursery sites, with a relative similarity in the abundance of Oligochaeta, Spionidae, Amage spp., Scrobicularia plana and Cerastoderma edule. Taking into consideration the generally opportunistic feeding ecology and low dietary selectivity of the flatfish species, the results indicated higher prey availability in the nursery grounds of the Portuguese estuaries, an important factor contributing to the quality of these areas. The relatively high macrobenthic productivity in the nursery areas might be linked to physical and biological interactions favouring the recruitment and maintenance of the communities.  相似文献   

Climate Change Policy Targets and the Role of Technological Change     

Marco A. Janssen  Bert de Vries 《Climatic change》2000,46(1-2):1-28

In this paper, we present results of simulationexperiments with the TIME-model on the issue ofmitigation strategies with regard to greenhouse gases.The TIME-model is an integrated system dynamics worldenergy model that takes into account the fact that the systemhas an inbuilt inertia and endogenouslearning-by-doing dynamics, besides the more commonelements of price-induced demand response and fuelsubstitution. First, we present four scenarios tohighlight the importance of assumptions on innovationsin energy technology in assessing the extent to whichCO₂ emissions have to be reduced. The inertia ofthe energy system seems to make a rise ofCO₂ emissions in the short term almostunavoidable. It is concluded that for the populationand economic growth assumptions of the IPCC IS92ascenario, only a combination of supply- anddemand-side oriented technological innovations incombination with policy measures can bring the targetof CO₂-concentration stabilization at 550 ppmv bythe year 2100 within reach. This will probably beassociated with a temporary increase in the overallenergy expenditures in the world economy. Postponingthe policy measures will be more disadvantageous,and less innovation in energy technology willhappen.  相似文献   

Consistent scale-dependency of future increases in hourly extreme precipitation in two convection-permitting climate models     

Helsen  Samuel  van Lipzig  Nicole P. M.  Demuzere  Matthias  Vanden Broucke  Sam  Caluwaerts  Steven  De Cruz  Lesley  De Troch  Rozemien  Hamdi  Rafiq  Termonia  Piet  Van Schaeybroeck  Bert  Wouters  Hendrik 《Climate Dynamics》2020,54(3):1267-1280

Climate Dynamics - Convection-permitting models (CPMs) have been proven successful in simulating extreme precipitation statistics. However, when such models are used to study climate change,...  相似文献   

Enhancing accessibility to web mapping systems with technology-aligned adaptive profiles     

Jacob Delfos  Bert Veenendaal  Tele Tan 《International Journal of Digital Earth》2014,7(4):256-278

Web-based geographic information systems have advanced rapidly on the back of web-based technologies, increased bandwidths and access to Digital Earth imagery and functionality. However, these advances are causing its capabilities to slowly overtake those of end-users. Additionally, the introduction of non-desktop devices such as smartphones, tablets and netbooks is starting to undo progress made towards standardisation of web-based technology. Large variations in screen sizes, computational power, bandwidth, and operating environments are once again introducing the need to ensure software remains functional across different platforms, standards-compliant or not. These two issues highlight the need for a mechanism to tune content and capability to end-users and their environment, to prevent information and complexity overload in a field already troubled by poor usability, while promoting cross-platform compatibility. This paper proposes the use of adaptivity to accommodate for users from different backgrounds accessing web mapping systems in different technical environments. It describes adaptive profiles aligned to the finite number of states a system can adopt, rather than the limitless range of user or environment characteristics that cannot be adapted to. Each profile consists of a combination of adaptive states comprising functionality, information detail, or technical demands to optimise for individual users or technical environments.  相似文献   

Analytical geospatial Digital Earth     

Bert Veenendaal  Songnian Li  Suzana Dragicevic  Maria Antonia Brovelli 《International Journal of Digital Earth》2014,7(4):253-255

  相似文献