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141.
In order to understand the influence of the South China Sea (SCS) water on the Kuroshio, and to study the dissolved carbonate system, we participated in six WOCE cruises aboard R/V Ocean Researcher 1. The areas studied were the northeast South China Sea and the West Philippine Sea near the Luzon Strait. Temperature, salinity, pH, alkalinity and total CO2 were measured. Our data indicate that, although the Kuroshio and the SCS waters flow in and out of the Luzon Strait near surface, the SCS water seems mainly to flow out of the SCS at mid-depth. There exists a mid-depth front near 122°E between 350 and 1350 m in all seasons and years that we studied. The water mass between 350 and 1350 m east of the front belongs to the West Philippine Sea proper water, while on the west is the mixed water of the South China Sea and the West Philippine Sea. 相似文献
142.
Rates of calcium carbonate dissolution and organic carbon decomposition in the North Pacific ocean 总被引:2,自引:0,他引:2
Chen-Tung Arthur Chen 《Journal of Oceanography》1990,46(5):201-210
Recent carbonate data collected in the North Pacific were combined with the data in the literature in order to understand more clearly the carbonate chemistry in the North Pacific. Our analyses show that inorganic CaCO3 dissolution contributes about 26% of the total inorganic CO2 increase of deep water, after leaving the Southern Ocean. The calcium and alkalinity data indicate a CaCO3 dissolution rate of 0.060±0.010 and 0.053±0.005 µ mol kg–1 yr–1 respectively, for waters deeper than 2,000 m in reference to the Weddell Sea Deep Water. The organic carbon decomposition rate is 0.107±0.012 µ mol kg–1 yr–1 while the oxygen consumption rate is 0.13±0.002 µ mol kg–1 yr–1. These results which are based on the direct comparison of two water masses agree well with other estimates which are based on methods such as the one-dimensional-diffusion-advection model. Comparison of data along the two sections at 165°E and 150°W shows no significant difference in the ratio of the CaCO3 dissolution rate and the organic carbon decomposition rate. The eastern section, however, has a higher TCO2 input than the western section because of the older age of the deep water along the eastern section. 相似文献
143.
The pore water concentrations of dissolved silica in sediment cores from the continental slope offshore from Cape Hatteras, North Carolina, varied from 150 to almost 700 μ,M with depth in the top 40 cm of sediment. Sediment cores from 630 to 2010 m depth had very similar profiles of dissolved silica in their pore waters, even though these cores came from regions greatly different in slope, topography, sedimentation rate, and abundance of benthic macrofauna. Cores from 474 to 525 m were more variable, both with respect to pore water dissolved silica profiles, and with respect to sediment texture. Experiments indicate that both the rate of dissolution of silica and the saturation concentration decrease as sediment depth below the sediment-seawater interface increases. These data are consistent with depletion of a reactive silica phase in surface sediment, which may be radiolarian tests, or the alteration of biogenic silica to a less reactive form over time. Experimental results suggest that the pore water dissolved silica concentration in sediments below the top few centimeters may be higher than the sediments could now achieve. The flux of dissolved silica out of these sediments is estimated to be 15 μmoles cm−2 yr−1. 相似文献
144.
Abstract Analysis of a two-layer, flat-bottom, steady-wind driven, eddy-resolving general circulation model reveals a distinct separation in frequency of baroclinic and barotropic motion in the region distant from the model Gulf Stream. The far-field motions at periods less (greater) than about 100 days are predominantly barotropic (baroclinic), unlike the near-field, eddy-generating, free-jet region which contains barotropic and baroclinic energy throughout the modei frequency range. The far-field barotropic energy produces a peak in the model sea-level spectra between 25 and 50 days with a magnitude comparable to energy levels observed in spectra of sea level from oceanic island tide gauges. The far-field barotropic motion is clearly composed of large-scale, resonant, barotropic normal modes drive by mesoscale activity of the turbulent, free-jet region. Oceanic mesoscale turbulence may therefore provide for planetary normal modes an excitation mechanism distinct from atmospheric forcing. The open-ocean, barotropic, model response is very similar to that of a fluctuating-wind driven model, which suggests that atmospheric and intrinsic forcing of mid-ocean eddies may be of comparable importance. 相似文献
145.
146.
GPS-GNSS Implementation and the Role of the National Civil Aviation Review Commission 总被引:1,自引:0,他引:1
Arthur Shantz 《GPS Solutions》1998,2(1):13-20
147.
Dalia Bach Kirschbaum Robert Adler Yang Hong Stephanie Hill Arthur Lerner-Lam 《Natural Hazards》2010,52(3):561-575
A systematic inventory of landslide events over the globe is valuable for estimating human and economic losses, quantifying
the relationship between landslide occurrences and climate variations and for evaluating emerging global landslide prediction
efforts based on remote sensing data. This study compiles a landslide catalog for rainfall-triggered events for several years,
drawing upon news reports, scholarly articles, and other hazard databases to provide a landslide catalog at the global scale.
While this database may only represent a subset of rainfall-triggered landslides globally, due to lack of reports, it presents
a lower boundary on the number of events globally and provides initial insight into the spatiotemporal statistical trends
in landslide distribution and impact. This article develops a methodology for landslide event compilation that can be used
in evaluating global landslide forecasting initiatives and assessing patterns in landslide distribution and frequency worldwide. 相似文献
148.
A distributed object-based rainfall–runoff simulation (DORS) model with incorporation of detailed impervious surface-area (ISA) data, derived from digital true-color orthophotography data with high spatial resolution, was developed. This physically based model simulates hydrologic processes of precipitation interception, infiltration, runoff, evapotranspiration, change of soil moisture, change of water-table depth, runoff routing, groundwater routing, and channel-flow routing. The modeling processes take objects based on land-cover types as fundamental spatial units in order to reduce data volume, increase computational efficiency, strengthen representation of watersheds, and utilize the data in variable scales. US Geological Survey stream-gaging data were used to validate the temporal variation of simulated discharge within two watersheds in Rhode Island State. The ratio of absolute error to the mean and the Nash coefficient in the validation period are 7.2% and 0.90 for the first watershed, and 8.0% and 0.77 for the second watershed, respectively. The results indicate that the DORS model is able to capture the relationship between rainfall and runoff in the study area, and that it is applicable in the further study of ISA impacts on the water cycle and associated pollution problems. The results also demonstrate that the performance of the hydrologic simulation is improved with ISA data with high spatial resolution. 相似文献
149.
Melanie G. Wiber Murray A. Rudd Evelyn Pinkerton Anthony T. Charles Arthur Bull 《Marine Policy》2010,34(3):598-605
Intertidal clam fisheries seem ideal candidates for the devolution of management authority from government to local stakeholders. In St. Mary's Bay, Nova Scotia, a private firm recently applied for a 10-year renewal of a large (1,627 ha) lease for quahog clam aquaculture. This case study examines the challenges of implementing community-based natural resource management (CBNRM) in rural fisheries within a broad integrated coastal management (ICM) institutional environment that favours corporate stakeholders. The challenges facing clam harvesters in rural Digby Neck, Nova Scotia arise from poor communication and coordination within government and between government and communities, as well as higher-level policy conflicts. The most important challenge arises from ‘stealth privatization’ of clam beaches. A single firm was granted rights of first refusal to depurate all clams harvested from closed (polluted) beaches in the region, resulting in the de facto privatization of all (polluted and unpolluted) clam beaches. Experiences in other parts of Canada suggest there may be community-based governance approaches that avoid the pitfalls associated with corporate management of clam beaches. New thinking is required about how to moderate the ‘privatization paradigm’ so prevalent within senior levels of government in order to ensure environmental and social sustainability in rural fishing communities. 相似文献
150.
Kandasamy Selvaraj Gopal Parthiban Chen-Tung Arthur Chen Jiann-Yuh Lou 《Continental Shelf Research》2010,30(10-11):1200-1210
Slag material was dumped in two sites off southwestern Taiwan by the China Steel Corporation during 1984–1995. By geochemically analyzing four sediment cores, we investigated the impact of slag on the sediment chemistry. Elemental profiles from the dumping sites show a strong depletion in detrital elements and enrichment in alkaline and redox-sensitive elements, especially for the top ~20 cm of sediments. The relative enrichment factor (EFrel) exhibits wider range for Ca (0.73–13.33), Fe (0.88–3.03), Mg (0.94–9.58) and Mn (1.22–33.30) due to contamination of sediments by slag. Sediment weathering indicators also show a distinct change with lower values in sediments influenced by dumping due to Ca and Sr addition. Higher EFrel for As, Cd and Pb in the top sections of the cores indicate an additional modern/industrial input of these elements since ~1950. Our study suggests that slag dumping may have a localized effect on biogeochemical processes by inducing the diagenetic remobilization of certain elements. 相似文献