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21.
Arthur Nanni Ari Roisenberg Maria Paula Casagrande Marimon Antonio Pedro Viero 《Environmental Geology》2009,58(6):1247-1255
Groundwater with high fluoride content and water mixture patterns were studied in Serra Geral aquifer system (SGAS) using
three aspects, principal component analysis (PCA), tectonic scenery and hydrochemical interpretation from 309 groundwater
chemical data information from deep wells. A four-component model is suggested and explains 81% of total variance in the PCA.
Six hydrochemical facies were identified. These facies suggest two different fluoride sources. Tectonic approach shows the
relationship between defined hydrochemical facies and regional fracture control. The applied methodology reveals a minimum
level to understand hydrochemical mixtures. The fluoride enrichment mechanisms into the groundwater are comprised in advance
to guide the future uses of SGAS to the public supply. 相似文献
22.
23.
Paleomagnetic study of specimens from four lamprophyric dykes on the Kukri Hills, Taylor Valley (77.64°S, 163.35°E) has yielded a primary mean direction of magnetization ofD=222.6 andI=+0.6 with 95=10.9° after AF cleaning. The magnetization of five other dykes and of the amphibolitic basement was either unstable or not fully reliable.The corresponding pole position lies at 9.3°S and 26.7°E and confirms the previous results from Lower Ordovician rocks from distant areas of East Antarctica.A Lower Ordovician mean pole position recalculated from valid data lies at 17°S, 21°E. 相似文献
24.
P. P. Alberoni S. Nanni M. Crespi M. Monai 《Meteorology and Atmospheric Physics》1996,58(1-4):123-138
Summary A case study of supercell thunderstorm development over Po Valley in northern Italy is discussed. The data were collected during MATREP, a field project operated in the month of June 1990. During the late morning hours of 8 June, before the passage of a cold front, a supercell and a single cell developed at the same time in eastern part of Po Valley, about 60 km apart from each other.Surface mesoscale analysis helps to explain these different storm evolutions due to interaction among local circulations, Adriatic Sea and orography. While dry wind (foehn) dumps the thermodynamic instability in single-cell environment, a moisture circulation affects the origin area of supercell. Computation of corresponding instability indices again supports the peculiar evolution of the two storms which is also analyzed by means of radar data.With 20 Figures 相似文献
25.
Summary We analyze surface air temperature historical data with a principal focus on the last one hundred years and on the Italian territory. We find, using only statistical methods that this area can be divided in two climatically homogeneous zones: in both of these zones we find a positive temperature trend for the last one hundred years. This trend is always steeper for the winter temperatures and more pronounced for northern than for southern stations. In the historical temperature series power spectrum we identify two broad significant peaks, one containing the well known quasi-biennial oscillation and the other either solar periodicity related to the inversion of the sun magnetic polarity (Hale cycle) or the North Atlantic ocean-atmosphere oscillation.With 7 Figures 相似文献
26.
Precipitation in Italy from 1833 to 1996 总被引：8，自引：1，他引：7
Summary Series of annual and seasonal precipitation from 32 stations, distributed over all Italian territory and divided in two groups
climatically homogeneous, were studied for the period 1833–1996. The series were checked for homogeneity and the time series
analysis was performed with the Mann Kendall test and its progressive application according to Sneyers (1990). The results
show considerably different trends for different seasons and zones. On a yearly basis a decreasing trend is present over all
Italy, but it is statistically significant only in the Central-South. On a seasonal basis a decreasing trend is significant
only for spring in Central-South, and for autumn in the North.
Received June 29, 1998 Revised October 16, 1998 相似文献
27.
Carlos Antonio da Silva Junior Marcos Rafael Nanni José Francisco de Oliveira-Júnior Everson Cezar Paulo Eduardo Teodoro Rafael Coll Delgado 《International Journal of Digital Earth》2019,12(3):270-292
This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS (Moderate-Resolution Imaging Spectroradiometer) images. Two major techniques were used: GEOgraphic-Object-Based Image Analysis (GEOBIA) and Data Mining (DM). In order to obtain the images, the segmentation algorithm implemented by Definiens Developer was used. A decision tree (DT) was created from a training set previously prepared. Time-series of images from the MODIS sensor aboard the Terra satellite were acquired in order to represent the wide variation of the vegetation pattern along the soybean crop cycle. The time-series data were used only for the CEI index. Furthermore, to compare the results obtained from GEOBIA, the slicing technique was used at the CEI level. After the training, the DT was applied to the vegetation indices generating the thematic map of the spatial distribution of soybean. In accordance with the error matrix and kappa parameter analysis, tests for statistical significance were created. Results indicate that the classification achieved by Kappa coefficients is 0.76. In short, the obtained results proved that combining vegetation indices and time-series data using GEOBIA return promising results for mapping soybean plantation on a regional scale. 相似文献
28.
Petitta Marco Mastrorillo Lucia Preziosi Elisabetta Banzato Francesca Barberio Marino Domenico Billi Andrea Cambi Costanza De Luca Gaetano Di Carlo Giuseppe Di Curzio Diego Di Salvo Cristina Nanni Torquato Palpacelli Stefano Rusi Sergio Saroli Michele Tallini Marco Tazioli Alberto Valigi Daniela Vivalda Paola Doglioni Carlo 《Hydrogeology Journal》2018,26(4):1009-1026
A seismic sequence in central Italy from August 2016 to January 2017 affected groundwater dynamics in fractured carbonate aquifers. Changes in spring discharge, water-table position, and streamflow were recorded for several months following nine Mw 5.0–6.5 seismic events. Data from 22 measurement sites, located within 100 km of the epicentral zones, were analyzed. The intensity of the induced changes were correlated with seismic magnitude and distance to epicenters. The additional post-seismic discharge from rivers and springs was found to be higher than 9 m3/s, totaling more than 0.1 km3 of groundwater release over 6 months. This huge and unexpected contribution increased streamflow in narrow mountainous valleys to previously unmeasured peak values. Analogously to the L’Aquila 2009 post-earthquake phenomenon, these hydrogeological changes might reflect an increase of bulk hydraulic conductivity at the aquifer scale, which would increase hydraulic heads in the discharge zones and lower them in some recharge areas. The observed changes may also be partly due to other mechanisms, such as shaking and/or squeezing effects related to intense subsidence in the core of the affected area, where effects had maximum extent, or breaching of hydraulic barriers.
相似文献29.
On the persistence of the 22 y solar cycle 总被引：2，自引：0，他引：2
We briefly discuss the existence of precise periodicities of the Hale cycle (-22 y), the Gleissberg cycle (-88 y), and -132 y cycle, in various direct and indirect indicators (as aurorae, 14C from tree rings and 10Be from polar ice) of solar activity. We consider also the behaviour of the 11y cycle and its first harmonic in modern sunspot series. It appears that the frequencies of -1 c/88 y and -1 c/132 y might be two subharmonics of the Hale cycle. The results support the hypothesis that the Sun behaves as a nonlinear system forced by an oscillator having the Hale frequency. The forcing element inside the Sun can be identified with a magnetofluid torsional oscillator. 相似文献
30.
Summary The trends and the fluctuations in variability of surface air temperature in Italy has been investigated by statistical analysis
of historical data covering the recent 100 years. 27 stations were used for the analysis and these were distributed all over
the Italian territory divided into two climatically homogeneous zones. The temperature trends are different in each climatic
zone and season, while the interannual variability shows a similar seasonal dependence for the North and South of Italy. In
particular, summer temperature shows a characteristic pattern with alternating minima and maxima reaching significant values
in the period 1940–1970: a maximum for the North between 1940–1960 and a minimum for the South between 1960–1970.
Received February 1, 1996 Revised June 7, 1997 相似文献