Evaluation of community leaders’ perception regarding Alerta Rio,the warning system for landslides caused by heavy rains in Rio de Janeiro     

Patricia de Oliveira Melo  Renata Marques de Britto  Tharcisio Cotta Fontainha  Adriana Leiras  Renata Albergaria de Mello Bandeira 《Natural Hazards》2017,89(3):1343-1368

Warning systems help reduce damage and save lives in disasters; however, there is a lack of research analyzing the population perception of these systems. In Rio de Janeiro (Brazil), because the city slums face the risk of landslides caused by heavy rains, a siren early warning system named “Alerta Rio” was installed in 102 areas. The purpose of this paper was to understand the perception of community leaders regarding this alert system. To this end, a survey was conducted with community leaders to collect data on whether and why the public do or do not attend to the alert. Results indicated that (1) public adherence to Alerta Rio is low despite the generally positive view of the system, (2) local violence was reported as the reason for staying at home to protect one’s property, and (3) problems with temporary shelters and the routes to them result in lack of people’s involvement in the system. Whereas these factors are similar to population perception regarding other warning systems, the community leaders also raised the public’s lack of trust in the city hall’s adopted concept of risk and in the politicians as a relevant factor in the population perception of Alerta Rio. These factors, together with the lack of prevention policies complementary with the alert system, led to perception of reduced importance of the system. For potential solutions to enhance alarm compliance, this study recommends improvement in communication, educational programs, and public engagement strategies tailored for each target group.  相似文献   

Identification of peneplains by multi‐parameter assessment of digital elevation models          下载免费PDF全文

Vicky L. Haider  Jan Kropáček  István Dunkl  Bianca Wagner  Hilmar von Eynatten 《地球表面变化过程与地形》2015,40(11):1477-1492

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HAND contour: a new proxy predictor of inundation extent          下载免费PDF全文

Antonio Donato Nobre  Luz Adriana Cuartas  Marcos Rodrigo Momo  Dirceu Luís Severo  Adilson Pinheiro  Carlos Afonso Nobre 《水文研究》2016,30(2):320-333

Tools for accurately predicting environmental risks, such as the location and spatial extent of potential inundation, are not widely available. A dependence on calibration and a lack of available flood data have prevented the widespread application of existing hydrodynamic methods for predicting the extent of inundation. We use the height above the nearest drainage (HAND) terrain model to develop a simple static approach for mapping the potential extent of inundation that does not depend on flood observations and extends beyond methods for mapping low‐lying areas. While relying on the contour concept, the method utilizes drainage‐normalized topography and flowpaths to delineate the relative vertical distances (drop) to the nearest river. The HAND‐delineated relative drop is an effective distributed predictor of flood potential, which is directly related to the river stage height. We validated the new HAND contour approach using a flood event in Southern Brazil for which high‐resolution maps were available. The results indicated that the flood hazard‐mapping method accurately predicted the inundation extent of the channel carrying the flood wave and the channels influenced by flooding. For channels positioned outside of the flood‐wave area, the method overestimated the actual flood extent. As an original static assessment of floodwaters across the landscape, the HAND contour method could be used to map flood hazards in areas with poor information and could promote the development of new methods for predicting hydrological hazards. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Atrazine effects on meiobenthic assemblages of a modular estuarine mesocosm     

Bejarano AC  Pennington PL  DeLorenzo ME  Chandler GT 《Marine pollution bulletin》2005,50(11):1398-1404

Atrazine is a widely used herbicide in the US found at levels ranging from <10 ng/L to 62.5 microg/L in estuaries throughout the southeast. Effects of atrazine on estuarine meiobenthic assemblages chronically exposed to environmentally relevant concentrations are unknown. The purpose of our research was to assess effects of atrazine on meiobenthos at concentrations near the proposed USEPA SWQC (26 microg/L) using modular estuarine salt marsh mesocosms as a field surrogate. Indigenous copepod and nematode densities were assessed after 28 days of exposure in transplanted colonization chambers. Cluster analysis showed a group characterized by low copepod densities, mostly atrazine exposed chambers, and a group containing all but one control chamber. The later group included chambers with high densities of the copepods Paronychocamptus wilsoni and Enhydrosoma baruchi. Compared to controls, copepod densities was approximately 70% lower in atrazine chambers, with three of the most common copepod species (E. baruchi, Onychocamptus sp. and P. wilsoni) showing an average of 50-70% reduction in population densities (p<0.05). Although nematode density did not differ between atrazine and control chambers, the nematode-to-copepod ratio was significantly higher in atrazine (9.95+/-7.61; p=0.011) than in control chambers (0.61+/-0.35). Our findings suggest that chronic exposures over multiple generations to atrazine at concentrations near the proposed USEPA SWQC could have significant effects on the abundance and composition of estuarine meiobenthic copepod assemblages.  相似文献   

The Newport line off Oregon - Studies in the North East Pacific     

Adriana Huyer  Patricia A. Wheeler  P. Ted Strub  Robert L. Smith  Ricardo Letelier  P. Michael Kosro 《Progress in Oceanography》2007,75(2):126-160

The Newport Hydrographic (NH) Line along 44.65°N off central Oregon was sampled seasonally during two epochs: 1961-1971 through the TENOC program and 1997-2003 through the GLOBEC Northeast Pacific Long Term Observations Program (LTOP); some observations are available for 2004 and 2005. During TENOC, the line extended 305 km offshore to 128°W, with stations 18 km apart over the continental shelf and 36 km offshore. During LTOP, the line was shorter (to 126°W) with closer station spacing over the continental shelf (9 km apart) and slope (18 km apart). LTOP cruises included biochemical sampling and underway current measurements. During both TENOC and LTOP, the seasonal cycle is very strong (accounting for >50% of the variance in surface layer properties), with rapid transitions in spring and fall. The summer regime is subject to coastal upwelling driven by southward winds, equatorward surface currents, and advection of low-salinity waters from the Columbia River. The winter regime off Newport is subject to coastal downwelling and poleward surface currents driven by northeastward winds. Comparison between TENOC and LTOP summer regimes shows the near-surface layer (0-100 m) at most locations is significantly warmer and fresher during LTOP than TENOC, and steric heights over the continental margin are significantly higher. Comparison of LTOP and TENOC winters shows that average differences at most locations were not statistically significant, but that the variance of steric height and shelf-break temperatures was significantly higher during LTOP than TENOC. Interannual variability of climate indices is also stronger during LTOP, which included a rare Subarctic invasion in 2002 as well as the strong 1997-1998 El Niño. During both TENOC and LTOP, interannual variability of steric height is closely related to the El Niño/La Niña cycle. Nutrient concentrations and nitrate-to-phosphate ratios of upwelling-source waters vary inversely with halocline temperature. Both reflect alongshore advection by coastal currents: southward currents bring cool, nitrate-rich waters in summer (especially during the Subarctic invasion), and northward currents bring relatively warm, nitrate-poor waters to the NH line in winter (especially during El Niño). Seasonal and interannual variations in the nutrient level of upwelling-source water are reflected in time series of vertically-integrated chlorophyll over the LTOP survey region (about 150 km by 300 km). Seasonal variations in chlorophyll and currents are congruent with seasonal variations in copepod biomass and diversity. We were not successful in establishing a clear connection between chlorophyll levels and interannual variations in copepod biomass or diversity, nor in explaining the large decrease in the survival rate of coho salmon between TENOC (6%) and LTOP (3%).  相似文献   

Coastal upwelling in the California current system     

Adriana Huyer 《Progress in Oceanography》1983,12(3):259-284

Coastal upwelling in the California Current system has been the subject of large scale studies off California and Baja California, and of small scale studies off Oregon. Recent studies of the winds along the entire coast from 25°N to 50°N indicate that there are significant along-shore variations in the strength of coastal upwelling, which are reflected in the observed temperature distribution. Active upwelling appears to be restricted to a narrow coastal band (about 10–25 km wide) along the entire coast, but the region influenced by coastal upwelling may be much wider. Intensive observations of the upwelling zone during summer off Oregon show the presence of a southward coastal jet at the surface, a mean vertical shear, a poleward undercurrent along the bottom, and persistently sloping isopycnals over the continental shelf; most of the upwelling there occurs during relatively short periods (several days long) of upwelling-favorable winds. During the upwelling season off Oregon, the offshore Ekman transport is carried by the surface Ekman layer, and the onshore return flow occurs through a quasi-geostrophic interior. It is not known whether the structure and dynamics observed off Oregon are typical of the upwelling zone along the entire coast, though some of the same features have been observed off Baja California. Current and future research will eventually show whether the Oregon results are also applicable in the region of persistently strong upwelling-favorable winds off northern California, and in the region of complex bathymetry off central and southern California.  相似文献   

A forecast of public water scarcity on Leu-Rotunda Plain,Romania, for the end of the 21st century     

Bianca Mitrică  Istvan Bogardi  Eugen Mitrică  Irena Mocanu  Marin Minciună 《Norsk geografisk tidsskrift. Norwegian journal of geography》2017,71(1):12-29

The article examines the risk of water shortages due to the climate change on Leu-Rotunda Plain, which is part of Oltenia Plain in Romania. The region has been exposed to several extreme climatic phenomena, mostly droughts, which has created several problems related to water quality and quantity. The authors defined climate change scenarios using two regional climate models. Water resources under climate change were estimated by a regional numerical groundwater model covering a deep aquifer. The water demand components were estimated for households, industries, services, and livestock, based on specific socio-economic assumptions. A non-probabilistic risk assessment, using simplified fuzzy sets mathematics, was used to estimate water supply, water demand, and the consequences of water shortages. The results of the study revealed significant vulnerability in the water supply, a limited territorial expansion of sewerage networks, an expected increase in households’ demand, an expected increase in industrial and services water demand, a relatively stable demand for water for livestock farming, and an important water shortage in the study area. The authors conclude by highlighting a set of actions to mitigate the risk of the potential crisis.  相似文献   

Quaternary ontogeny of a pampean ‘laguna’     

Nauris V. Dangavs  Adriana M. Blasi 《Journal of Paleolimnology》1994,10(1):59-66

Our sedimentological study of Lobos Lake sediments has shown that, below modern deposits, there is a clastic and biological record of three different paleoenvironments: two aquatic (freshwater and mixohaline respectively) and one subaereal. This record documents the climatic and geomorphologic changes that affected the basin during its evolution up to its present water level, from the upper Pleistocene to the Holocene.This is the seventh in a series of papers published in this issue on Paleolimnology in Southern South America. Dr. C. A. Fernández served as guest editor for these papers.  相似文献   

Melt evolution in felsic dikes inferred from the composition of gahnite in two new occurrences,Pala Chief and Elizabeth R composite dikes,California     

Adriana Heimann  Jason A. Yonts  Michael A. Wise 《Mineralogy and Petrology》2016,110(6):731-746

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The role of volatile exsolution and sub-solidus fluid/rock interactions in producing high Fe/Fe ratios in siliceous igneous rocks     

Adriana Heimann  Brian L. Beard  Clark M. Johnson 《Geochimica et cosmochimica acta》2008,72(17):4379-4396

Highly differentiated igneous rocks can, in some cases, have ⁵⁶Fe/⁵⁴Fe ratios that are significantly higher than those of mafic- to intermediate-composition igneous rocks. Iron isotope compositions were obtained for bulk rock, magnetite, and Fe silicates from well-characterized suites of granitic and volcanic rocks that span a wide range in major- and trace-element contents. Sample suites studied include granitoids from Questa, N.M. (Latir volcanic field) and the Tuolumne Intrusive Series (Sierra Nevada batholith), and volcanic rocks from Coso, Katmai, Bishop Tuff, Grizzly Peak Tuff, Seguam Island, and Puyehue volcano. The rocks range from granodiorite to high-silica granite and basalt to high-silica rhyolite. The highest δ⁵⁶Fe values (up to +0.31‰) are generally restricted to rocks that have high Rb (>100 ppm), Th (>∼15 ppm) and SiO₂ (>70 wt.%) but low Fe (<2 wt.% total Fe as Fe₂O₃) contents. Magnetite separated from these rocks has high δ⁵⁶Fe values, whereas Fe silicates have δ⁵⁶Fe values close to zero. Although in principle crystal fractionation might explain the high δ⁵⁶Fe values, trace-element ratios in high-δ⁵⁶Fe igneous rocks indicate that crystal fractionation is an unlikely explanation. The highest δ⁵⁶Fe values occur in volcanic and plutonic rocks that contain independent evidence for fluid exsolution, including sub-chondritic Zr/Hf ratios, suggesting that loss of a low-δ⁵⁶Fe ferrous chloride fluid is the most likely explanation for the high δ⁵⁶Fe values in the bulk rocks. Based on magnetite solubility in chloride solutions and predicted Fe isotope fractionations among Fe silicates, magnetite, and ferrous chloride fluids, the increase in δ⁵⁶Fe values of bulk rocks may be explained by isotopic exchange between magnetite and , which predicts an increase in the δ⁵⁶Fe values of magnetite upon fluid exsolution. This model is consistent with the δ⁵⁶Fe values measured in this study for bulk rocks, as well as magnetite and Fe silicates. Our results suggest that fluid exsolution from siliceous hydrous magmas, which sometimes produce porphyry-style Cu, Mo, or Cu-Au mineralization, may be traced using Fe isotopes.  相似文献