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41.
Marcello Antonio Ventura Gorini Guilherme Lucio Abelha Mota 《International journal of geographical information science》2016,30(8):1644-1666
A method is presented to explicitly incorporate spatial and scale vagueness – double vagueness – into geomorphometric analyses. Known limitations of usual practices include using a single fixed set of crisp thresholds for morphometric classification and the imposition of a single arbitrary number of scales of analysis to the entire digital elevation model (DEM). Among the advantages of the proposed method are: fuzzification of morphometric classification rules, scale-dependent adaptive fuzzy set parametrization and an objective definition of maximum scale of analysis on a cell-by-cell basis. The method was applied to several DEMs ranging from the ocean floor to surface landscapes of both Earth and Mars. The result was evaluated with respect to modal morphometric features and to characteristic scales, suggesting a more robust method for deriving both morphometric classifications and terrain attributes. We argue that the method would be preferable to any single-scale crisp approach, at least in the context of preliminary hands-off morphometric analyses of DEMs. 相似文献
42.
43.
Effects of oil on phytoplankton metabolism in natural and experimental estuarine ponds 总被引:1,自引:0,他引:1
Armando A. De La Cruz 《Marine environmental research》1982,7(4):257-263
A low level oil spill was simulated in small shallow natural estuarine marsh ponds in Ocean Springs and in experimental impoundments near St. Louis Bay, Mississippi. In the natural tidal pond in situ light and dark BOD bottle experiments on the phytoplankton community revealed a 44 to 65 % reduction in primary production and a 30 to 50 % reduction in respiration 2 weeks after spillage of 1·45 mg Empire Mix crude oil per litre of water. Two months after the spill, primary productivity and respiration in the oiled pond were only 17% and 7% lower, respectively than in the control pond. In the experimental impoundments at a concentration of 0·2 mg Arabian, Empire Mix and Nigerian oil per litre of water, in situ radiocarbon uptake by phytoplankton was lower—but not significantly lower—than that of the control impoundment. One to two months later, primary productivity was significantly higher in the Nigerian and Arabian oil ponds than control and Empire Mix ponds. The changes in plankton metabolism in both natural ponds and impoundments were evaluated on the basis of data simultaneously obtained from adjoining control ponds. 相似文献
44.
Pamela L. Nagler Armando Barreto-Muñoz Sattar Chavoshi Borujeni Christopher J. Jarchow Martha M. Gómez-Sapiens Hamideh Nouri Stefanie M. Herrmann Kamel Didan 《水文研究》2020,34(25):4851-4883
Hydrological and bioclimatic processes that lead to drought may stress plants and wildlife, restructure plant community type and architecture, increase monotypic stands and bare soils, facilitate the invasion of non-native plant species and accelerate soil erosion. Our study focuses on the impact of a paucity of Colorado River surface flows from the United States (U.S.) to Mexico. We measured change in riparian plant greenness and water use over the past two decades using remotely sensed measurements of vegetation index (VI), evapotranspiration (ET) and a new annualized phenology assessment metric (PAM) for ET. We measure these long-term (2000–2019) metrics and their short-term (2014–2019) response to an environmental pulse flow in 2014, as prescribed under Minute 319 of the 1944 Water Treaty between the two nations. In subsequent years, small-directed flows were provided to restoration areas under Minute 323. We use 250 m MODIS and 30 m Landsat imagery to evaluate three vegetation indices (NDVI, EVI, EVI2). We select EVI2 to parameterize an optical-based ET algorithm and test the relationship between ET from Landsat and MODIS by regression approaches. Our analyses show significant decreases in VIs and ET for both the 20-year and post-pulse 5-year periods. Over the last 20 years, EVI Landsat declined 34% (30% by EVIMODIS) and ETLandsat-EVI declined 38% (27% by ETMODIS-EVI), overall ca. 1.61 mm/day or 476 mm/year drop in ET; using PAM ETLandsat-EVI the drop was from 1130 to 654 mm/year. Over the 5 years since the 2014 pulse flow, EVILandsat declined 20% (13% by EVIMODIS) and ETLandsat-EVI declined 23% (4% by ETMODIS-EVI) with a 0.77 mm/day or a 209 mm/year 5-year drop in ET; using PAM ETLandsat-EVI the drop was from 863 to 654 mm/year. Data and change maps show the pulse flow contributed enough water to slow the rate of loss, but only for the very short-term (1–2 years). These findings are critically important as they suggest further deterioration of biodiversity, wildlife habitat and key ecosystem services due to anthropogenic diversions of water in the U.S. and Mexico and from land clearing, fires and plant-related drought which affect hydrological processes. 相似文献
45.
Aguilar-Meléndez Armando Pujades Lluis G. Barbat Alex H. Monterrubio-Velasco Marisol de la Puente Josep Lantada Nieves 《Natural Hazards》2022,110(3):1649-1691
Natural Hazards - There are personal and institutional decisions that can increase the seismic resilience of the buildings in a city. However, some of these decisions are possible if we have basic... 相似文献
46.
硒是与生物密不可分的微量元素,其含量和赋存形态对人们的生产生活至关重要,本文选择典型富硒地区陕西紫阳,测定该地区地层中29个不同岩性岩石样品的Se含量,探明了该区岩石组合主要以富硒的碳质板岩、硅质岩、黑色页岩和含黄铁矿煤样为主,而在灰岩中硒的富集程度不强。选取14个典型富硒岩石和煤样品,通过四步五态顺序提取法,阐明了硒的五种赋存形态特征及其环境地球化学意义:陕西紫阳地区岩石硒形态以硫/硒化物结合状态为主,残渣态、有机结合状态硒次之,紫阳地区沉积环境偏还原性。本文为深入认识陕西紫阳地区富硒岩石硒含量和硒迁移转化行为及富硒矿产资源综合开发利用提供了数据基础和理论指导。 相似文献
47.
Vincenzo Orofino Armando Blanco Marcella D’Elia Sergio Fonti Domenico Licchelli 《Planetary and Space Science》2009,57(5-6):632-639
Searching for traces of extinct and/or extant life on the surface of Mars is one of the major objectives for remote-sensing and in-situ exploration of the planet. In the present paper we study the infrared (IR) spectral modifications induced by thermal processing on differently preserved calcium carbonate fossils, in order to discriminate them from their abiotic counterparts.The main conclusion of this study is that the degree of alteration of the fossils, derived from IR spectral analysis, seems to be well correlated with the sample age, and that terrestrial fossils after a billion years are so altered that it becomes impossible to trace their biotic origin. Since it is reasonable to assume that the putative Martian fossils should be at least 3.5 billion years old, this would imply that our spectroscopic method could not be able to detect them, if their degradation rate were the same as that we have found in usual conditions for the terrestrial fossils. However, due to the different climate evolution of the two planets, there is the possibility of having two different degradation rates, much lower for Mars than for Earth, especially if the fossils are embedded in a protective layer, such as a clay deposit. In this case IR spectroscopy, coupled with thermal processing, can be a useful tool for discriminating between abiotic and biotic (fossil) carbonate samples collected on the Martian surface. 相似文献
48.
Paolo de Bernardis Martin Bucher Carlo Burigana Lucio Piccirillo 《Experimental Astronomy》2009,23(1):5-16
B-Pol is a medium-class space mission aimed at detecting the primordial gravitational waves generated during inflation through
high accuracy measurements of the Cosmic Microwave Background polarization. We discuss the scientific background, feasibility
of the experiment, and implementation developed in response to the ESA Cosmic Vision 2015-2025 Call for Proposals.
See for the full list of collaboration members and a full copy of the B-Pol proposal. 相似文献
49.
Carbonaceous materials in size-segregated atmospheric aerosols from urban and coastal-rural areas at the Western European Coast 总被引:1,自引:1,他引:0
Regina M.B.O. Duarte Cludia L. Mieiro Ana Penetra Casimiro A. Pio Armando C. Duarte 《Atmospheric Research》2008,90(2-4):253-ICNAA07
A high-volume cascade impactor, equipped with a PM10 inlet, was used to collect size-segregated aerosol samples during the summer of 2004 at two Portuguese locations: a coastal-rural area (Moitinhos) and an urban area (Oporto). Concentrations of airborne particulate matter (PM), total carbon (TC), organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) were determined for the following particle size ranges: < 0.49, 0.49–0.95, 0.95–3.0, and 3.0–10 µm. The total PM mass concentrations at the urban and coastal-rural sites ranged from 22.8 to 79.6 μg m− 3 and 19.9 to 28.2 μg m− 3, respectively, and more than 56% of the total aerosol mass was found in the fractions below 3.0 μm. At both locations the highest concentrations of OC and EC were found in the submicrometer size range. The regional variability for the OC and EC concentrations, with the highest concentrations being found in the urban area, was related to the contribution of local primary sources (mostly traffic emissions). It was also verified an enrichment of the small size particles in WSOC, representing on average 37.3(± 12.4)% and 59.7(± 18.0)% of OC in the very fine aerosol at the coastal-rural and urban areas, respectively. The amount of secondary OC calculated by the minimum OC/EC ratio method indicates that secondary organic aerosol formation was important throughout the study at both sites. The obtained results suggest that long-range transport and favourable summer conditions for photochemical oxidation are key factors determining secondary OC formation in the coastal-rural and urban areas. The ultraviolet absorption properties of the chromophoric constituents of the WSOC fractions were also different among the different particle size ranges and also between the two sampling locations, thus suggesting the strong impact of the diverse emission sources into the composition of the size-segregated organic aerosol. 相似文献
50.