819 resultados para Water and sewerage. Regulation. Efficiency. Data envelopment Analysis (DEA). Malmquist index


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A comprehensive hydroclimatic data set is presented for the 2011 water year to improve understanding of hydrologic processes in the rain-snow transition zone. This type of dataset is extremely rare in scientific literature because of the quality and quantity of soil depth, soil texture, soil moisture, and soil temperature data. Standard meteorological and snow cover data for the entire 2011 water year are included, which include several rain-on-snow events. Surface soil textures and soil depths from 57 points are presented as well as soil texture profiles from 14 points. Meteorological data include continuous hourly shielded, unshielded, and wind corrected precipitation, wind speed, air temperature, relative humidity, dew point temperature, and incoming solar and thermal radiation data. Sub-surface data included are hourly soil moisture data from multiple depths from 7 soil profiles within the catchment, and soil temperatures from multiple depths from 2 soil profiles. Hydrologic response data include hourly stream discharge from the catchment outlet weir, continuous snow depths from one location, intermittent snow depths from 5 locations, and snow depth and density data from ten weekly snow surveys. Though it represents only a single water year, the presentation of both above and below ground hydrologic condition makes it one of the most detailed and complete hydro-climatic datasets from the climatically sensitive rain-snow transition zone for a wide range of modeling and descriptive studies.

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We compare total and biogenic particle fluxes and stable nitrogen isotope ratios (d15N) at three mooring sites along a productivity gradient in the Canary Islands region with surface sediment accumulation rates and sedimentary d15N. Higher particle fluxes and sediment accumulation rates, and lower d15N were observed in the upwelling influenced eastern boundary region (EBC) compared to the oligotrophic sites north of Gran Canaria [European Station for Time-Series in the Ocean, Canary Islands (ESTOC]] and north of La Palma (LP). The impact of organic matter degradation and lateral particle advection on sediment accumulation was quantified with respect to the multi-year flux record at the ESTOC. Remineralisation of organic matter in the water column and at the sediment surface resulted in an organic carbon preservation of about 0.8% and total nitrogen preservation of about 0.4% of the estimated export production. Higher total and carbonate fluxes and accumulation rates in the lower traps and surface sediment compared to the upper traps indicated that at least 50% of the particulate matter at the ESTOC was derived from allochthonous sources. Low d15N values in the lower traps of the ESTOC and LP point to a source region influenced by coastal upwelling. We conclude from this study that the reconstruction of export production or nutrient regimes from sedimentary records in regions with strong productivity gradients might be biased due to the mixture of particles originating from autochthonous and allochthonous sources. This could result in an imprint of high productivity signatures on sedimentation processes in oligotrophic regions.

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Data are presented on concentration of hydrocarbons (HC) relative to concentrations of suspended matter, lipids, organic carbon, and chlorophyll a in surface waters and snow-ice cover of the East Antarctic coastal areas. It was shown that growth of concentrations of aliphatic HC (AHC) to 30 µg/l in surface waters takes place in frontal zones and under young ice formation. AHC concentration in snow increases with growth of aerosol concentration in the atmosphere. In the lower part of ice, at the boundary with seawater, despite low temperatures, autochthonous processes may provide high AHC concentrations (up to 289 µg/l). Within the snow-ice cover on fast ice, concentration co-variations of all the compounds considered take place.

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The distribution of seagrass and associated benthic communities on the reef and lagoon of Low Isles, Great Barrier Reef, was mapped between the 29 July and 29 August 1997. For this survey, observers walked or free-dived at survey points positioned approximately 50 m apart along a series of transects. Visual estimates of above-ground seagrass biomass and % cover of each benthos and substrate type were recorded at each survey point. A differential handheld global positioning system (GPS) was used to locate each survey point (accuracy ±3m). A total of 349 benthic survey points were examined. To assist with mapping meadow/habitat type boundaries, an additional 177 field points were assessed and a georeferenced 1:12,000 aerial photograph (26th August 1997) was used as a secondary source of information. Bathymetric data (elevation below Mean Sea Level) measured at each point assessed and from Ellison (1997) supplemented information used to determine boundaries, particularly in the subtidal lagoon. 127.8 ±29.6 hectares was mapped. Seagrass and associated benthic community data was derived by haphazardly placing 3 quadrats (0.25m**2) at each survey point. Seagrass above ground biomass (standing crop, grams dry weight (g DW m**-2)) was determined within each quadrat using a non-destructive visual estimates of biomass technique and the seagrass species present identified. In addition, the cover of all benthos was measured within each of the 3 quadrats using a systematic 5 point method. For each quadrat, frequency of occurrence for each benthic category was converted to a percentage of the total number of points (5 per quadrat). Data are presented as the average of the 3 quadrats at each point. Polygons of discrete seagrass meadow/habitat type boundaries were created using the on-screen digitising functions of ArcGIS (ESRI Inc.), differentiated on the basis of colour, texture, and the geomorphic and geographical context. The resulting seagrass and benthic cover data of each survey point and for each seagrass meadow/habitat type was linked to GPS coordinates, saved as an ArcMap point and polygon shapefile, respectively, and projected to Universal Transverse Mercator WGS84 Zone 55 South.

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Oceanographic data collected by ocean research organisations in Russia, the USA, the United Kingdom, Germany, Norway, and Poland for the Barents, Kara and White Seas region are presented in this atlas. Recently declassified naval data from Norway, the USA, and the UK are also included. More than 1,000,000 oceanographic stations containing temperature and/or sea-water salinity data were originally selected. After correcting errors and eliminating duplicates, data from 206,300 checked stations were placed on CD-ROM, together with many figures describing the characteristics of both the single-input and combined data set. In addition, temperature and salinity measurements were interpolated to the following standard horizons: 0, 25, 50, 100, 150, 200, 250, 300 m, and bottom. This atlas covers the 100-year period 1898 to 1998 and is, to date, the most complete oceanographic data collection for these Arctic shelf seas. This data set is complemented by more than 9,000 measurements of sea surface temperature, which were recently digitized from ships' logbooks. They cover the same geographical area within the time period 1867-1912.

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We have measured the 3He/3He and 3He/20 Ne ratios of thirty-nine pore water and gas samples in deep-sea sediments collected at twelve sites on the Pacific Ocean bottom during the cruises of Deep Sea Drilling Project Legs 87, 89, 90 and 92. The 3He/4He and 4He/20Ne ratios vary from 0.000000215 to 0.00000165 and from 0.29 to 20, respectively. He in the sample is composed of four components: (1) atmospheric He dissolved in seawater; (2) atmospheric He with mantle-derived He in Pacific bottom water; (3) in situ radiogenic He in the sediment; and (4) crustal He in the basement rock. Assuming that the 20Ne contents are constant with the value of seawater, the depth variations in the 4He/20Ne ratios at five Sites, 583D, 594, 597A, 598A and 504B, may provide useful information on 4He flux at the ocean bottom. The estimated 4He fluxes vary from 2000 to 40000 atoms cm**-2 s**-1 and are one to three orders of magnitude less than those calculated from the excess He in deep ocean water. An overall similarity between the geographical distribution of the 3He/4He ratios and heat flow data is found in the study area, between the East Pacific Rise across the Pacific Ocean and the Japanese Islands. The tendency is well explained by a conventional sea-floor spreading model.