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71.
Variability of the salinity in the western Wadden Sea on tidal to centennial time scales 总被引:1,自引:1,他引:0
Daily observations of the salinity of the Marsdiep tidal inlet, which connects the Dutch western Wadden Sea with the North Sea, already started over 140 years ago, in 1860. Since the year 2000 the sampling frequency has increased because of the use of electronic sensors. Analysis of these salinity data have revealed variations on time scales from tidal (~ 12 hour), seasonal, inter-annual, and multi-decadal, to centennial. The contributions of the salinity variations in the Marsdiep for these different spectral bands or time scales are all of the order of a standard deviation of 0.5 to 1. The centennial variation, which can be expressed as a 140 year long salinity trend, is related to engineering works on the rivers Rhine and IJssel, which already started in the early 18-th century, and more than doubled the magnitude of the freshwater content of the western Wadden Sea since then. In contrast with this anthropogenic salinity trend, the climatic variability of the precipitation over western Europe, and the connected changes in the Rhine discharge, are mainly responsible for the inter-annual variations in the salinity and/or freshwater content of the western Wadden Sea. Since variations in salinity and freshwater content also reflect variations in the terrigeneous and river influence on the Wadden ecosystem, e.g. via the nutrient content, it can be expected that the ecology of the Wadden Sea also experienced changes on centennial time scales. 相似文献
72.
Tell es‐Sâfi/gath is situated in the semiarid foothills of central Israel, adjacent to the coastal . plain. An enigmatic landscape feature, noted on aerial photographs, encircles the tell on three sides. This unique feature, unknown from other Near Eastern tells, was investigated. Methods of analysis include aerial photographs, field surveys, excavations, soil analyses, chronotypological ceramic classification, and radiocarbon dating. We concluded that (1) the peculiar landscape feature is a huge human‐made trench, over 2 km long, 5–6 m deep, and more than 8 m wide, cut through bedrock; (2) the trench was excavated during the Iron Age IIA (ca. 1000–800 B.C.E.), apparently as part of a siege system; (3) the extracted rock and soil material was dumped on the Iron Age landscape surface on one side of the trench, forming an elevated “berm”; (4) erosion processes transformed this landscape scar, as the trench filled with sediment; (5) stratigraphic analysis indicates two major phases of filling, separated by a period of landscape stability and soil formation (A horizon); (6) the two filling phases, exhibiting Iron Age IIA and Byzantine pottery (ca. 324—638 C.E.), appear to coincide with more intense human activity; and (7) the possible effect of climatic variations seems less obvious. © 2005 Wiley Periodicals, Inc. 相似文献
73.
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
74.
He Qing Xing Lid Zhang Jianping Martin G. Lockley Hendrik Klein W. Scott Persons IV Qi Liqi Jia Chengkai 《《地质学报》英文版》2013,87(6):1477-1485
A pterosaur-bird track assemblage from a sandstone-siltstone-mudstone sequence of the Lower Cretaceous Tugulu Group of Xinjiang comprises the first pterosaur track record from this province and the largest specimen thus far known from China.The pterosaur tracks are assigned to the ichnogenus Pteraichnus based on the triangular overall-shape,the four elongate digit traces and the robust manual digit trace Ⅲ.Supposed trackmakers were dsungaripterid pterodactyloids whose skeletal remains are well known from the Tugulu Group.The bird tracks that occur on the same surface,are those of typical shorebirds,known from different other localities in southeast Asia.The congruence with Koreanaornis dodsoni described from the same stratigraphic level justifies an assignment to this ichnospecies.This is a further evidence of the co-occurrence of pterosaurs and birds in a typical iakeshore environment with possible seasonal alteration of water supply and aerial exposure indicated by wave ripples,mudcracks and repeated cycles of coarse to fine sediment.Pterosaurs and birds frequented the shoreline and may have fed also on the numerous invertebrates such as the Scoyenia tracemaker that left abundant burrows. 相似文献
75.
Stephanie Wegscheider Tobias Schneiderhan Alexander Mager Hendrik Zwenzner Joachim Post Günter Strunz 《Natural Hazards》2013,68(1):181-195
Earthquakes and other sudden onset natural disasters require quick and efficient emergency response. Earth observation (EO) data can make a valuable contribution to emergency response efforts if provided within hours and at the most days after the event. Mechanisms like the International Charter Space and Major Disasters and the European GMES Emergency Response Service provide the necessary basis for an efficient and rapid provision of EO data and damage mapping. This paper provides an overview of earthquake damage assessment methodologies, their potential and their limitations in a rapid mapping context and outlines a methodology for casualty estimation. Two case studies—the 2010 Haiti earthquake and the 2011 Van (Turkey) earthquake—are presented, where DLR’s Center for satellite-based crisis information (ZKI) provided rapid damage maps using a team-based visual interpretation approach. Additionally, the application of a casualty estimation method in the immediate aftermath of an earthquake is outlined. 相似文献
76.
Anita Peter Hendrik Lamert Matthias Beyer G?tz Hornbruch Ben Heinrich Alexandra Schulz Helmut Geistlinger Ben Schreiber Peter Dietrich Ulrike Werban Carsten Vogt Hans-Hermann Richnow Jochen Gro?mann Andreas Dahmke 《Environmental Earth Sciences》2012,67(2):335-349
A small scale and temporally limited CO2 injection test was performed in a shallow aquifer to investigate the geochemical impact of CO2 upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO2 was injected over a ten-day period at three injection wells, at a depth of 18?m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO2, pH and electrical conductivity. Due to CO2 injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO2 and/or the alteration of groundwater. 相似文献
77.
Lindsay M. Upiter Jesse C. Vermaire R. Timothy Patterson Carley A. Crann Jennifer M. Galloway Andrew L. Macumber Lisa A. Neville Graeme T. Swindles Hendrik Falck Helen M. Roe Michael F. J. Pisaric 《Journal of Paleolimnology》2014,52(1-2):11-26
We analyzed subfossil chironomids, sediment organic matter and sediment particle size data from a 1.11-m-long freeze core collected from Carleton Lake (unofficial name), located approximately 120 km north of the modern treeline. This well-dated core spans the last ca. 6,500 years. Two chironomid transfer functions were applied to infer mean July air temperatures. Our results indicated that the chironomid-inferred temperatures from this lake sediment record did not pass a significance test, suggesting that other factors in addition to temperature may have been important in structuring the chironomid community through time. Although not statistically significant, the chironomid-inferred temperatures from this site do follow a familiar pattern, with highest inferred temperatures occurring during the Holocene Thermal Maximum (~6–4 cal kyr BP), followed by a long-term cooling trend, which is reversed during the last 600 years. The largest change in the chironomid assemblage, which occurred between ca. 4,600 and 3,900 cal yr BP is possibly related to the well-documented northward advance and subsequent retreat of treeline in this region. 相似文献
78.
A large Luneberg-type antenna with accessories is described as a means of simultaneously monitoring a large number of stars for possible intelligent signals. Various contacting strategies are compared on their probability of success and arguments are advanced favoring a program of transmission at a wavelength of 21 cm to the nearest stars. 相似文献
79.
80.
A diatom-based Holocene record of human impact from a coastal environment: Tuckean Swamp, eastern Australia 总被引:1,自引:0,他引:1
Kathryn H. Taffs Luc J. Farago Hendrik Heijnis Geraldine Jacobsen 《Journal of Paleolimnology》2008,39(1):71-82
Diatom-based paleolimnological studies are being increasingly used to track anthropogenic change in estuaries. Little is known,
however, about the direction and nature of long-term environmental changes in Australian estuaries. In this study, shifts
in diatom assemblages preserved in a 210Pb and C14 AMS dated sediment core from Tuckean Swamp were analysed to determine environmental changes that had taken place as a result
of changing land-use practices. Prior to European impact, the diatom assemblage remained relatively stable and was dominated
by Actinocyclus normanii and Diploneis smithii. An increasing dominance of Cyclotella meneghiniana correlates well with changed land use activities in the catchment area and indicates an increase of freshwater influence
in the swamp’s environment. A major shift in species composition began ∼1970, Eunotia flexuosa becoming dominant. The assemblage shifts recorded at this site appear to be consistent with environmental changes triggered
by human activities such as vegetation clearance, drainage and the construction of a barrage. This study demonstrates the
use of paleolimnoology in an estuarine environment to provide pre-impact data necessary for management of the aquatic environment. 相似文献