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11.
Andrew Swales R. Bruce Williamson Laurence F. Van Dam Morag J. Stroud Matt S. McGlone 《Estuaries and Coasts》2002,25(1):43-56
Cores were collected from the length of Pakuranga estuary, a small urban estuary in Auckland, New Zealand, to determine sedimentation
and contaminant history, and in particular the impact of urbanization. Catchment sediment loads for the most recent history
(1953–1995), including urbanization since 1960, were reconstructed using the landcover history and soil erosion modeling.
Pollen and14C dating and pre-urban landcover history were used to reconstruct early estuary sedimentation (i.e., post-3000 yr BP to 1960).
Heavy metal concentrations, particle size,137Cs, pollen, and catchment sediment loads were all needed to disentangle the complex estuarine response to urbanization.137Cs profiles did not reflect the historical fallout pattern, but deposition of137Cs-labelled eroded catchment soil, coinciding with peaks in urban construction. Temporal variations in stormwater137Cs concentrations are likely due to varying contributions from137Cs-rich topsoil and137Cs-poor subsoils. A similar pattern was observed in heavy-metal concentrations and attributed to street runoff rather than
topsoil being diluted by metal-poor subsoils. Dating of the sediment profiles showed that during urbanization sedimentation
rates in the tidal creek and estuary were higher than sedimentation rates associated with past agricultural landuse and the
original forest landcover. Urbanization has brought about substantial environmental changes in the upper estuary through continued
infilling of shallow, intertidal areas, contamination by heavy metals to levels of ecological concern, sediment textural changes,
and rapid mangrove colonization of formerly bare intertidal sediments. 相似文献
12.
T. Hilbig M. Weber K. Bramstedt S. Noël J. P. Burrows J. M. Krijger R. Snel M. Meftah L. Damé S. Bekki D. Bolsée N. Pereira D. Sluse 《Solar physics》2018,293(8):121
This paper describes a new reference solar spectrum retrieved from measurements of the satellite instrument SCIAMACHY in the wavelength region from \(0.24~\upmu\mbox{m}\) to \(2.4~\upmu\mbox{m}\) and its comparison with several other established solar reference spectra. The SCIAMACHY reference spectrum was recorded early in the mission before substantial optical degradation due to the harsh space environment sets in. The radiometric calibration of SCIAMACHY, applied in this study, includes a physical model of the scanner unit. Furthermore, SCIAMACHY’s internal white light source (WLS) is used to correct for on-ground to in-flight changes. The resultant calibrated solar spectrum from SCIAMACHY is in good agreement with several available solar spectral irradiance (SSI) references in the visible spectral range. Strong throughput losses due to detector icing in the near infrared (NIR) are now adequately accounted for. Nevertheless, a deficit with respect to the ATLAS-3 composite and SORCE/SIM SSI is observed in the NIR. However, the SCIAMACHY solar reference spectrum agrees well with the recently re-evaluated SOLAR/SOLSPEC-ISS and recent ground measurements taken at Mauna Loa in the NIR. 相似文献
13.
Results of mercury and organochlorine analyses in pooled muscle and blubber samples representing in all 417 long-finned pilot whales (Globicephala melas) sampled in 1997 in the Faroe Islands are presented. The 28 pooled muscle samples from (in all) 9 pods were analysed for total mercury and the same number of pooled blubber samples were analysed for PCB (IUPAC CBs no. 28, 52, 99, 101, 105, 118, 128, 138, 153, 170, 180, 183 and 187), p,p′-DDT and metabolites and o,p′-DDT and metabolites, cis () and trans (γ)-chlordane, cis- and trans-nonachlor, oxychlordane, mirex, hexachlorobenzene, β-HCH and toxaphene (Parlars no. 26 (T2), 32, 50 (T12), 62 (T20) and 69. 相似文献
14.
Summary This paper discusses the causes of the current wave of renewal and relocation of football stadiums in the Netherlands and tries to shed some light on the changing form and location of Dutch football stadiums. Comparison with developments in the United Kingdom shows not only remarkable resemblances and mutual influences, but also some significant differences. In an inextricable upward spiral of causes and consequences such as recent successes of clubs and the national team, rising attendances, increasingly positive media attention, rising interests of commercial investors, new international and national requirements on stadium construction and an increasingly positive attitude of municipalities, a new wave of stadium redevelopment and relocation has emerged in the Netherlands. In this paper it will become clear that every stadium tells its own story; some of these stories are highlighted. 相似文献
15.
Journal of Oceanology and Limnology - A new species Lobophora tsengii is described from Bach Long Vy (Bailongwei) Island, Haiphong Province, Vietnam. The plants inhabit the subtidal zone and have... 相似文献
16.
Efficient scheme for the shallow water equations on unstructured grids with application to the Continental Shelf 总被引:1,自引:1,他引:0
Herman W. J. Kernkamp Arthur Van Dam Guus S. Stelling Erik D. de Goede 《Ocean Dynamics》2011,61(8):1175-1188
In this paper, a shallow-water flow solver is presented, based on the finite-volume method on unstructured grids The method
is suitable for flows that occur in rivers, channels, sewer systems (1D), shallow seas, rivers, overland flow (2D), and estuaries,
lakes and shelf breaks (3D). We present an outline of the numerical approach and show three 2D test cases and an application
of tidal propagation on the Continental Shelf. The benefits of applying an unstructured grid were explored by creating an
efficient model network that aims at keeping the number of grid cells per wavelength constant. The computational speed of
our method was compared with that of WAQUA/TRIWAQ and Delft3D (the commonly used structured shallow-flow solvers in The Netherlands),
and comparable performance was found. 相似文献
17.
We have used a high spatial and temporal resolution of long time sequence of spectra in CaII H-line obtained at the Vacuum
Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet region at the center of the solar disk over a large number
of bright points and network elements to search for atmospheric (chromospheric) g-mode oscillations. An important parameter
of the H-line profile, intensity at H2v(Ih2V), has been derived from a large number of line profiles. We derived the light curves of all the bright points and network
elements. The light curves represent the main pulse with large intensity amplitude and followed by several follower pulses
with lower intensity amplitudes. The light curves of these bright points would give an impression that one can as well draw
curves towards and away from the highest peak (main pulse) showing an exponential growth and decay of the amplitudes. An exponential
decaying function has been fitted for all the light curves of the bright points to determine the damping time of the modes
that are more or less the same, and one value of the coefficient of exponent can represent reasonably well the decay for all
the cases. The FFT analysis of temporal variation of both the bright points and the network elements indicates around 10-min
periodicity. We speculate that this longer period of oscillation may be related to chromospheric g-mode oscillations. 相似文献
18.
Earth System Mass Transport Mission (e.motion): A Concept for Future Earth Gravity Field Measurements from Space 总被引:1,自引:0,他引:1
I. Panet J. Flury R. Biancale T. Gruber J. Johannessen M. R. van den Broeke T. van Dam P. Gegout C. W. Hughes G. Ramillien I. Sasgen L. Seoane M. Thomas 《Surveys in Geophysics》2013,34(2):141-163
In the last decade, satellite gravimetry has been revealed as a pioneering technique for mapping mass redistributions within the Earth system. This fact has allowed us to have an improved understanding of the dynamic processes that take place within and between the Earth’s various constituents. Results from the Gravity Recovery And Climate Experiment (GRACE) mission have revolutionized Earth system research and have established the necessity for future satellite gravity missions. In 2010, a comprehensive team of European and Canadian scientists and industrial partners proposed the e.motion (Earth system mass transport mission) concept to the European Space Agency. The proposal is based on two tandem satellites in a pendulum orbit configuration at an altitude of about 370 km, carrying a laser interferometer inter-satellite ranging instrument and improved accelerometers. In this paper, we review and discuss a wide range of mass signals related to the global water cycle and to solid Earth deformations that were outlined in the e.motion proposal. The technological and mission challenges that need to be addressed in order to detect these signals are emphasized within the context of the scientific return. This analysis presents a broad perspective on the value and need for future satellite gravimetry missions. 相似文献
19.
Yuteng Ma Remke L. Van Dam Dushmantha H. Jayawickreme 《Environmental Earth Sciences》2014,72(5):1367-1381
In deciduous forests, soil moisture is an important driver of numerous physical, microbial, and biogeochemical processes. Therefore, characterizing the interactions between vegetation and soil moisture is critical to forecast long-term water resources and ecosystem health. However, these interactions are difficult to measure, both in time and space. Recent studies have shown the ability of electrical resistivity imaging (ERI) to characterize the spatial and temporal dynamics of soil moisture at a range of scales. However, no study has yet attempted to use ERI to describe spatiotemporal variability of soil water in relation to vegetation structure and throughfall. In this study, at a mature forest site in Michigan, USA, we captured spatial and temporal dynamics of soil moisture using weekly ERI measurements augmented with throughfall and soil temperature measurements, and a detailed vegetation survey for five adjacent quadrats. Our results show that throughout the growing season, the soil moisture gradually declined despite strong variations in cumulative monthly rainfall. This decline was occasionally halted, but not reversed, during weeks with high precipitation. Spatial variability of electrical resistivity and soil moisture was not related to soil temperature differences but showed a strong correlation with canopy variables. 相似文献
20.
Most GPS coordinate time series, surface displacements derived from the Gravity Recovery and Climate Experiment (GRACE), and loading models display significant annual signals at many regions. This paper compares the annual signals of the GPS position time series from the Crustal Dynamics Data Information System (CDDIS), estimates of loading from GRACE monthly gravity field models calculated by three processing centers (Center of Spatial Research, CSR; Jet Propulsion Laboratory, JPL; GeoForschungsZentrum, GFZ) and three geophysical fluids models (National Center for Environmental Prediction, NCEP; Estimating the Circulation and Climate of the Ocean, ECCO; Global Land Data Assimilation System, GLDAS) for 270 globally distributed stations for the period 2003-2011. The results show that annual variations derived from the level-2 products from the three GRACE product centers are very similar. The absolute difference in annual amplitude between any two centers is never larger than 1.25 mm in the vertical and 0.11 mm in horizontal displacement. The mean phase differences of the GRACE results are less than ten days for all three components. When we correct the GPS vertical coordinate time series using the GRACE annual amplitudes using the products from three GRACE analysis centers, we find that we are able to reduce the GPS annual signal in the vertical at about 80% stations and the average reduction is about 47%. In the north and the east, the annual amplitude is reduced on 77% and 72% of the stations with the average reduction 32% and 33%. We also compare the annual surface displacement signal derived from two environmental models; the two models use the same atmospheric and non-tidal ocean loading and differ only in the continental water storage model that we use, either NCEP or GLDAS. We find that the model containing the GLDAS continental water storage is able to better reduce the annual signal in the GPS coordinate time series. 相似文献