Discrete‐Storm Water‐Table Fluctuation Method to Estimate Episodic Recharge          下载免费PDF全文

John R. Nimmo  Charles Horowitz  Lara Mitchell 《Ground water》2015,53(2):282-292

We have developed a method to identify and quantify recharge episodes, along with their associated infiltration‐related inputs, by a consistent, systematic procedure. Our algorithm partitions a time series of water levels into discrete recharge episodes and intervals of no episodic recharge. It correlates each recharge episode with a specific interval of rainfall, so storm characteristics such as intensity and duration can be associated with the amount of recharge that results. To be useful in humid climates, the algorithm evaluates the separability of events, so that those whose recharge cannot be associated with a single storm can be appropriately lumped together. Elements of this method that are subject to subjectivity in the application of hydrologic judgment are values of lag time, fluctuation tolerance, and master recession parameters. Because these are determined once for a given site, they do not contribute subjective influences affecting episode‐to‐episode comparisons. By centralizing the elements requiring scientific judgment, our method facilitates such comparisons by keeping the most subjective elements openly apparent, making it easy to maintain consistency. If applied to a period of data long enough to include recharge episodes with broadly diverse characteristics, the method has value for predicting how climatic alterations in the distribution of storm intensities and seasonal duration may affect recharge.  相似文献   

Metal concentrations, fluxes, inventories and chronologies in sediments from Sepetiba and Ribeira Bays: A comparative study     

Franciane de Carvalho Gomes  Jos Marcus Godoy  Maria Luiza D.P. Godoy  Zenildo Lara de Carvalho  Ricardo Tadeu Lopes  Joan Albert Sanchez-Cabeza  Luiz Drude de Lacerda  Julio Cesar Wasserman 《Marine pollution bulletin》2009,59(4-7):123

Three sediment cores were sampled at Sepetiba Bay and four cores at Ribeira Bay, Rio de Janeiro State, Brazil. Sediment accumulation rates and chronologies were obtained from ²¹⁰Pb activity-depth profiles. Sediment accumulation rates in Ribera Bay ranged from 1.2 mm y⁻¹ in the inner bay to 2.6 mm y⁻¹ close to its entrance. In Sepetiba Bay two sediment accumulation rates were observed: a lower rate of 0.35 cm y⁻¹ before the 1960s and 0.76 cm y⁻¹ since then. The cause of this change is due to the construction of the Santa Cecília impoundment (1955) that brings water from the Paraíba do Sul Basin into the Guandu River, which increased its flow from the original 20 m³ s⁻¹ to 160 m³ s⁻¹. Concentration of 44 elements was obtained by ICP-MS after total dissolution of samples from two selected cores. The relative differences between the concentrations of crustal elements, such as Al, Fe and Ti are only about 20% (p < 0.05). Cd and Zn are 15 and four times larger in Sepetiba Bay than in Ribeira Bay, respectively. Other major and minor elements show lower statistically significant differences. The enrichment factors and metal inventories show that Sepetiba Bay can be considered polluted with Bi, Cd, Cr, Cu, Sb and Zn. Particularly, Cd and Zn present concentrations three and four times higher than the Brazilian existing limits.  相似文献   

Riverine input of particulate material and inorganic nutrients to a coastal reef ecosystem at the Caribbean coast of Costa Rica     

Cornelia Roder  Jorge Cortés  Carlos Jiménez  Rubén Lara 《Marine pollution bulletin》2009,58(12):1937-1943

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Petrophysical and mechanical properties of Euganean trachyte and implications for dimension stone decay and durability performance     

Luigi Germinario  Siegfried Siegesmund  Lara Maritan  Claudio Mazzoli 《Environmental Earth Sciences》2017,76(21):739

Euganean trachyte is a subvolcanic porphyritic rock extracted in northern Italy with an age-old tradition of use as dimension stone, historically linked, in particular, to the fervent building activity brought by the Roman Empire and, later on, the Republic of Venice Serenissima. The results of a comprehensive petrophysical and mechanical characterization of Euganean trachyte from the most representative quarries are discussed here, involving the following properties: density, porosity, water absorption, capillary water uptake, hygroscopic water adsorption, hydric/hygric dilatation, water vapor diffusion, thermal expansion, and resistance to salt attack and abrasion. The different trachyte varieties, although belonging to the same quarry basin, exhibit a relatively wide array of technical performances, which are strongly dependent on pore volume, size, size distribution, shape, and degree of interconnection, controlling modes and rates of water transport and retention. Therefore, indications are provided for evaluating durability performance of the stone, with stress on water-driven weathering. Complementary information is finally given on the possible criteria followed in the antiquity for properly selecting the trachyte quarries to be exploited, and by a comparison with the properties of the most important trachytes extracted in Europe.  相似文献   

Susceptibility to gravitational processes due to land cover change in the Río Chiquito-Barranca del Muerto subbasin(Pico De Orizaba Volcano,México)     

Rocío Marisol Alanís-Anaya  Gabriel Legorreta-Paulín  Jean François Mas  Guadalupe Rebeca Granados-Ramírez 《山地科学学报》2017,14(12):2511-2526

Land cover change can lead to slope instability by accelerating erosive processes associated with agriculture, forestry, and infrastructure. The Rio Chiquito-Barranca del Muerto subbasin has experienced an increase in land cover change due to government programs and the establishment of agricultural and urban areas. The aim of this study was to provide a model to map the susceptibility to gravitational processes along sites where anthropogenic land cover change has occurred. The method was based on the stratification of the subbasin according to landforms and cartographic variables. These variables were used in a multi-criteria assessment to assign weights according to their contribution to the onset of new gravitational processes. Those weights were used to create a susceptibility map based on a weighted linear sum. The accuracy of the resulting map was validated in an error matrix with a random stratified design based on susceptibility classes per landform. The results produced a map of areas with susceptibility to gravitational processes due to land cover change; this susceptibility is very high in the undifferentiated pyroclastic slope and limestone mountain, where it derives not only from anthropogenic effects on natural vegetation cover, but also from steep slopes, weathered materials, low apparent density, high erosivity, and previous gravitational processes. The results support other studies that concluded that loss of vegetation is a triggering factor in the formation of gravitational processes, but also show that excessive reforestation can increase gravitational processes.  相似文献   

Temperature variability in central Mexico and its possible association to solar activity     

B. Mendoza  A. Lara  D. Maravilla  E. Juregui 《Journal of Atmospheric and Solar》2001,63(18):25

Minimum extreme temperature variability from five meteorological stations in the central part of Mexico covering a period from 1920 to 1990 is examined. We found a correlation coefficient (r=0.65) between these temperature records and geomagnetic activity. Furthermore, by performing spectral analysis peaks were obtained with similar periodicities to those found in the sunspot number, the magnetic solar cycle, cosmic ray fluxes and geomagnetic activity; all of these phenomena are modulated by solar activity. Signals with periodicities comparable to those observed in El Niño and the Quasi-Biennial Oscillation were also identified. We conclude that the solar signal is probably present in the minimum extreme temperature record of the central part of Mexico.  相似文献   

Effect of macrofaunal bioturbation on bacterial distribution in marine sandy sediments, with special reference to sulphur-oxidising bacteria     

Marisol Goi-Urriza  Xavier de Montaudouin  Rmy Guyoneaud  Guy Bachelet  Rutger de Wit 《Journal of Sea Research》1999,41(4):170

We have studied the impact of the bioturbating macrofauna, in particular the lugworm Arenicola marina and the bivalve Cerastoderma edule, on abundances and distribution patterns of total bacteria and of bacteria of selected functional groups in sandy intertidal sediments. The selected groups comprised the colourless sulphur-oxidising bacteria and the anoxygenic phototrophic bacteria, which are expected to occupy small zones at the oxygen–sulphide interface in stable (non-bioturbated) sediments. The presence of a wooden wreck buried in the sediment at 10 cm depth within a large area of intertidal sand flat colonised by lugworms provided a unique opportunity to confront field observations with laboratory simulations. The site with the wooden wreck, which was used as control site, was devoid of both A. marina and C. edule, while the composition of the rest of the zoobenthic community was rather similar to that of the surrounding area. In the field, the density of total bacteria was approximately one order of magnitude higher in the control site than in the natural (bioturbated) site. This can be explained by the higher contents of silt and clay particles (higher surface-area/volume ratio) and higher total organic-carbon contents found at the control site. It appears that the presence of macrofauna affects sedimentation processes, which indirectly influence bacterial dynamics. Samples from the control site have been incubated in the laboratory with A. marina and C. edule added (bioturbated core), while an unamended core served as a control. The laboratory experiments contrasted with the field observations, because it was found that total bacteria were actually higher in the deeper layers of the bioturbated core. Moreover, the populations were more homogeneous (less stratified) and colourless sulphur bacteria were on average less numerous in the bioturbated core. In general, laboratory incubations resulted in a decrease of total bacteria with a concomitant increase of colourless and phototrophic sulphur-oxidising bacteria and thus in modifications of the bacterial community structure. Hence, our results demonstrate that care must be taken in extrapolating results from laboratory experiments (e.g. mesocosm research) to field situations.  相似文献   

Magnetic flux emergence and geomagnetic activity,a close correlation     

Mendoza  B.  Lara  A.  Maravilla  D.  Valdés-galicia  J.F. 《Solar physics》1999,185(2):405-416

We analyse data of magnetic flux emergence for solar cycles 21 and 22, Helios 1 interplanetary shocks for cycle 21, and sudden storm commencements (SSCs) for cycles 11–22. A dominant variation of 3-year periodicity was found for all three phenomena during cycles 21 and 22. This indicates a correlation and a possible influence of the rate of solar magnetic flux emergence to produce the interplanetary phenomena studied in this work; in particular, the suggested role of coronal mass ejections as a means by which magnetic flux and stresses are taken out of the corona seems to be plausible. When taking cycles 11–22 in SSCs, the main periodicity changes to around 4 years; this may be an indication of flux emergence rate variations over the cycles.  相似文献   

Geoprospecting Survey in the Archaeological Site of <Emphasis Type="Italic">Aquinum</Emphasis> (Lazio,Central Italy)     

Maurizio Lazzari  Lara De Giorgi  Giuseppe Ceraudo  Raffaele Persico 《Surveys in Geophysics》2018,39(6):1167-1180

In this paper, the results of a ground penetrating radar (GPR) prospecting survey performed in the Roman archaeological site of Aquinum are shown. The prospecting was performed in two distinct areas. The first one was close to the remains of the ancient thermal baths, where a public project intends to build a car park. The second area is close to an apsidal Roman building, and it was of interest to establish whether, and possibly up to what extent, the remains of this partially revealed structure continue, or maybe whether meaningful further structures are present.  相似文献