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361.
Cemeteries are understudied integral components to urban watersheds, which provide ecosystem services but can also export nutrients, trace elements, and other contaminants to nearby water bodies. In this study, we focus on Meadowbrook Creek, an urban headwater stream in Syracuse, New York (USA), which has shown significant nitrate contributions from a local cemetery. We collected biweekly surface water samples over the course of 1 year from 2022 to 2023 for analysis of major and trace elemental concentrations including Na, Ca, Mg, K, F, Cl, sulfate, and nitrate. Here, we aim to assess the impact of various human infrastructures on urban stream water quality with a particular focus on the cemetery and nitrate. A comparison between the new dataset in this study and previously reported water chemistry data in Meadowbrook in 2012 suggests a decade-long impact of road salting and the cemetery on water quality particularly with respect to Na, Cl, and nitrate. Sulfate, Mg, Ca, and K are likely mainly geogenic. Stable nitrogen isotope data, the usage of concrete or steel vaults in the cemetery in the past 50 years, and the lack of correlation between nitrate and fluoride concentrations in stream water argue against burial decay products being a major source of nitrate to the stream. Instead, other nitrate sources that exist in the cemetery such as, fertilizer, decaying plant material, and wastewater, are more viable dominant nitrate sources. In addition, nitrate loading calculations indicate that the groundwater-connected reach, including the cemetery, acts as an annual net sink for nitrate despite the seasonally varying sink-source patterns. 相似文献
362.
Necessary technical experience is being gained from successful construction and deployment of current prototype detectors to search for UHE neutrinos in Antarctica, Lake Baikal in Russia, and the Mediterranean. The prototype detectors have also the important central purpose of determining whether or not UHE neutrinos do in fact exist in nature by observation of at least a few UHE neutrino-induced leptons with properties that are not consistent with expected backgrounds. We discuss here the criteria for a prototype detector to accomplish that purpose in a convincing way even if the UHE neutrino flux is substantially lower than predicted at present. 相似文献
363.
Summary. Geomagnetic time-variations observed at several sites on the island of Hawaii are analysed for the effects of island bathymetry as well as for the inductive response of the deeper mantle. The data are generally consistent with the deep conductivity profile derived using lower frequency, electromagnetic data from the Island of Oahu. Hawaii data fit better if that model is modified to give the upper 200 km of the mantle a lower conductivity of 0.02 S/m compared to 0.1 S/m for Oahu. The data are represented by a complex, frequency-dependent function of location, T u , relating the vertical variation Z to a component U of the horizontal variation ( Tu = Z/U ). The direction of U is nearly frequency independent at each site but is different for each site. Below a frequency of about 30 cycles per day, the functions, T u , at any two sites are found to be related by a real constant. This suggests that the deeper conductivity structure is the same beneath each site. This result is consistent with quasi-static induction in a non-uniformly conducting thin sheet above a stratified conductivity structure. The response of such a model can be written as T u = Aq , where q is a quasi-uniform, complex, frequency-response function characterizing the effect of the deep conductivity and A is a spatially dependent parameter parameterizing the effect of variable conductivity in the thin sheet. The parameter A may be estimated by fitting observational estimates of T u to models of deep conductivity structure. 相似文献
364.
Biological interest in the exploration of Mars is briefly described as is the biological experiments package to be flown as part of the Viking 1975 lander payload. 相似文献
365.
M. Klein 《地球表面变化过程与地形》1981,6(2):173-178
The study deals with the relationship between specific conductance and water flow in a small catchment. Three flow types were studied: (a) channel flow; (b) overland flow; (c) subsurface flow. The study of the three flow types demonstrates the important role of the flushing effect in small basins. The flushing effect is seen as an increase in water conductivity in the early stage of an event. Flushing is probably a function of accumulation in the basin. Accumulation is best defined as a function of time elapsing since the last heavy rain. The study has been carried out in the School of Geography at Leeds University, Leeds LS2 9JT, England. 相似文献
366.
Gerrit de Leeuw Leo Cohen Lise Marie Frohn Gary Geernaert Ole Hertel Bjarne Jensen Tim Jickells Laura Klein Gerard J. Kunz Soren Lund Marcel Moerman Frank Müller Britta Pedersen Knut von Salzen K. Heinke Schlünzen Michael Schulz Carsten A. Skjth Lise-Lotte Sorensen Lucinda Spokes Susanne Tamm Elisabetta Vignati 《Continental Shelf Research》2001,21(18-19)
The aim of the atmospheric nitrogen inputs into the coastal ecosystem (ANICE) project is to improve transport–chemistry models that estimate nitrogen deposition to the sea. To achieve this, experimental and modelling work is being conducted which aims to improve understanding of the processes involved in the chemical transformation, transport and deposition of atmospheric nitrogen compounds. Of particular emphasis within ANICE is the influence of coastal zone processes. Both short episodes with high deposition and chronic nitrogen inputs are considered in the project. The improved transport–chemistry models will be used to assess the atmospheric inputs of nitrogen compounds into the European regional seas (the North Sea is studied as a prototype) and evaluate the impact of various emission reduction strategies on the atmospheric nitrogen loads. Assessment of the impact of atmospheric nitrogen on coastal ecosystems will be based on comparisons of phytoplankton nitrogen requirements, other external nitrogen inputs to the ANICE area of interest and the direct nitrogen fluxes provided by ANICE. Selected results from both the experimental and modelling components are presented here. The experimental results show the large spatial and temporal variability in the concentrations of gaseous nitrogen compounds, and their influences on fluxes. Model calculations show the strong variation of both concentrations and gradients of nitric acid at fetches of up to 25 km. Aerosol concentrations also show high temporal variability and experimental evidence for the reaction between nitric acid and sea salt aerosol is provided by size-segregated aerosol composition measured at both sides of the North Sea. In several occasions throughout the experimental period, air mass back trajectory analysis showed connected flow between the two sampling sites (the Weybourne Atmospheric Observatory on the North Norfolk coast of the UK and Meetpost Noordwijk, a research tower at 9 km off the Dutch coast). Results from the METRAS/SEMA mesoscale chemistry transport model system for one of these cases are presented. Measurements of aerosol and rain chemical composition, using equipment mounted on a commercial ferry, show variations in composition across the North Sea. These measurements have been compared to results obtained with the transport–chemistry model ACDEP which calculates the atmospheric inputs into the whole North Sea area. Finally, the results will be made available for the assessment of the impact of atmospheric nitrogen on coastal ecosystems. 相似文献
367.
M. Wyss F. Klein K. Nagamine S. Wiemer 《Journal of Volcanology and Geothermal Research》2001,106(1-2)
The pattern of b-value of the frequency–magnitude relation, or mean magnitude, varies little in the Kaoiki-Hilea area of Hawaii, and the b-values are normal, with b=0.8 in the top 10 km and somewhat lower values below that depth. We interpret the Kaoiki-Hilea area as relatively stable, normal Hawaiian crust. In contrast, the b-values beneath Kilauea's South Flank are anomalously high (b=1.3–1.7) at depths between 4 and 8 km, with the highest values near the East Rift zone, but extending 5–8 km away from the rift. Also, the anomalously high b-values vary along strike, parallel to the rift zone. The highest b-values are observed near Hiiaka and Pauahi craters at the bend in the rift, the next highest are near Makaopuhi and also near Puu Kaliu. The mildest anomalies occur adjacent to the central section of the rift. The locations of the three major and two minor b-value anomalies correspond to places where shallow magma reservoirs have been proposed based on analyses of seismicity, geodetic data and differentiated lava chemistry. The existence of the magma reservoirs is also supported by magnetic anomalies, which may be areas of dike concentration, and self-potential anomalies, which are areas of thermal upwelling above a hot source. The simplest explanation of these anomalously high b-values is that they are due to the presence of active magma bodies beneath the East Rift zone at depths down to 8 km. In other volcanoes, anomalously high b-values correlate with volumes adjacent to active magma chambers. This supports a model of a magma body beneath the East Rift zone, which may widen and thin along strike, and which may reach 8 km depth and extend from Kilauea's summit to a distance of at least 40 km down rift. The anomalously high b-values at the center of the South Flank, several kilometers away from the rift, may be explained by unusually high pore pressure throughout the South Flank, or by anomalously strong heterogeneity due to extensive cracking, or by both phenomena. The major b-value anomalies are located SSE of their parent reservoirs, in the direction of motion of the flank, suggesting that magma reservoirs leave an imprint in the mobile flank. We hypothesize that the extensive cracking may have been acquired when the anomalous parts of the South Flank, now several kilometers distant from the rift zone, were generated at the rift zone near persistent reservoirs. Since their generation, these volumes may have moved seaward, away from the rift, but earthquakes occurring in them still use the preexisting complex crack distribution. Along the decollement plane at 10 km depth, the b-values are exceptionally low (b=0.5), suggesting faulting in a more homogeneous medium. 相似文献
368.
Bathmetric highs on the old crust proximal to ridge-transform intersections (RTIs), termed intersection highs, are common but poorly understood features at offsets of fast to intermediate rate spreading centers. We have combined new reflection seismic, photographic, and geochemical data with previously published Seabeam, SeaMARC I, and SeaMARC II data to address the nature of the intersection highs at the Clipperton Fracture Zone. The Clipperton Intersection Highs are both topped by a carapace of young lavas at least 100 m thick. These lavas, which were erupted on the intersection highs, are chemically similar to their adjacent ridge segments and different from the surrounding older crust. At least some of the erupted magma traveled directly from the adjacent ridge at a shallow crustal level. Ridge-related magma covers and intrudes at least the upper 500 m of the transform tectonized crust at the RTI. We suspect that additional magma enters the intersection highs from directly below, without passing through the ridge. The young oceanic crust near the western Clipperton RTI is not thin by regional comparison. The 1.4 m.y. old crust near the eastern Clipperton RTI thickens approaching the transform offset. If the thermal effects of the proximal ridge were negligible, the eastern intersection high crust would appear to be in isostatic equilibrium. We believe that thermal effects are significant, and that the intersection high region stands anomalously shallow for its crustal thickness. This is attributable to increased temperature in the mantle below the ridge-proximal crust. Although ridge magma is injected into the proximal old crust, plate boundary reorganization is not taking place. Intersection high formation has been an ongoing process at both of the Clipperton RTIs for at least the past 1 m.y., during which time the plate boundary configuration has not changed appreciably. We envision a constant interplay between the intruding ridge magma and the disrupting transform fault motion. In addition, we envision a nearly constant input of magma from below the high, as an extension of the magma supply to the ridge from the mantle. Because the proximal ridge profoundly affects the juxtaposed crust at the RTI, sea floor fabric along the aseismic extensions of this fast-slipping transform fault is primarily a record of processes at work at the RTI rather than a record of transform tectonism. 相似文献
369.
Radio observations of Jupiter have been carried out at Goldstone, CA at a wavelength of 13 cm during the oppositions of 1969 and 1971. In 1969, circular-polarization and total-flux measurements were made with a 64-m radio telescope. From May through October 1971, Jupiter's flux density was measured at weekly intervals with a 26-m antenna. Analysis of the 2 years of data has yielded the following results: (a) The upper limit to the degree of circular polarization over the longitude ranges 10–100° and 160–250° System III (1957.0) is 1%; (b) the flux data have been used to derive a magnetospheric rotation period which is approximately 0.37s longer than the IAU System III (1957.0); (c) the flux-density data define beaming curves which are apparently different from 11-cm beaming curves measured in 1964; (d) Jupiter's peak flux density decreased by ~20% between 1964 and 1971, and 8% between 1969 and 1971. 相似文献
370.
Matthew C. Wyant Christopher S. Bretherton Julio T. Bacmeister Jeffrey T. Kiehl Isaac M. Held Ming Zhao Stephen A. Klein Brian J. Soden 《Climate Dynamics》2006,27(2-3):261-279
Low-latitude cloud distributions and cloud responses to climate perturbations are compared in near-current versions of three leading U.S. AGCMs, the NCAR CAM 3.0, the GFDL AM2.12b, and the NASA GMAO NSIPP-2 model. The analysis technique of Bony et al. (Clim Dyn 22:71–86, 2004) is used to sort cloud variables by dynamical regime using the monthly mean pressure velocity ω at 500 hPa from 30S to 30N. All models simulate the climatological monthly mean top-of-atmosphere longwave and shortwave cloud radiative forcing (CRF) adequately in all ω-regimes. However, they disagree with each other and with ISCCP satellite observations in regime-sorted cloud fraction, condensate amount, and cloud-top height. All models have too little cloud with tops in the middle troposphere and too much thin cirrus in ascent regimes. In subsidence regimes one model simulates cloud condensate to be too near the surface, while another generates condensate over an excessively deep layer of the lower troposphere. Standardized climate perturbation experiments of the three models are also compared, including uniform SST increase, patterned SST increase, and doubled CO2 over a mixed layer ocean. The regime-sorted cloud and CRF perturbations are very different between models, and show lesser, but still significant, differences between the same model simulating different types of imposed climate perturbation. There is a negative correlation across all general circulation models (GCMs) and climate perturbations between changes in tropical low cloud cover and changes in net CRF, suggesting a dominant role for boundary layer cloud in these changes. For some of the cases presented, upper-level clouds in deep convection regimes are also important, and changes in such regimes can either reinforce or partially cancel the net CRF response from the boundary layer cloud in subsidence regimes. This study highlights the continuing uncertainty in both low and high cloud feedbacks simulated by GCMs. 相似文献