Mediterranean forest mapping using hyper-spectral satellite imagery   总被引：2，自引：0，他引：2  

Selma Etteieb  Mounir Louhaichi  Chariton Kalaitzidis  Ioannis Z. Gitas 《Arabian Journal of Geosciences》2013,6(12):5017-5032

Mediterranean forests are characterized by spatiotemporal heterogeneity that is associated with Mediterranean climate, floristic biodiversity and topographic variability. Satellite remote sensing can be an effective tool for characterizing and monitoring forest vegetation distribution within these fragmented Mediterranean landscapes. The heterogeneity of Mediterranean vegetation, however, often exceeds the resolution typical of most satellite sensors. Hyper-spectral remote sensing technology demonstrates the capacity for accurate vegetation identification. The objective of this research is to determine to what extent forest types can be discriminated using different image analysis techniques and spectral band combinations of Hyperion satellite imagery. This research mapped forest types using a pixel-based Spectral Angle Mapper (SAM), nearest neighbour and membership function classifiers of the object-oriented classification. Hyperion classification was done after reducing Hyperion data using nine selected band combinations. Results indicate that the selection of band combination while reducing the Hyperion dataset improves classification results for both the overall and the individual forest type accuracy, in particular for the selected optimum Hyperion band combination. One shortcoming is that the performance of the best selected band combination was superior in terms of both overall and individual forest type accuracy when applying the membership classifier of the object-oriented method compared to SAM and nearest neighbour classifiers. However, all techniques seemed to suffer from a number of problems, such as spectral similarity among forest types, overall low energy response of the Hyperion sensor, Hyperion medium spatial resolution and spatiotemporal and spectral heterogeneity of the Mediterranean ecosystem at multiple scales.  相似文献   

Simplified formulae for the BIQUE estimation of variance components in disjunctive observation groups   总被引：7，自引：1，他引：6  

N. Crocetto  M. Gatti  P. Russo 《Journal of Geodesy》2000,74(6):447-457

 General rigorous and simplified formulae are reported for the best invariant quadratic unbiased estimates of the variance–covariance components, which can be applied to all least-squares adjustments with the general linear stochastic model. Simplified procedures are given for two cases frequently recurring in geodetic applications: uncorrelated groups of correlated or uncorrelated observations, with more than one variance component in each group. Received: 19 November 1998 / Accepted: 21 March 2000  相似文献   

Search for contact,systems among EB-type binaries     

F. Barone  E. Covino  L. Di Fiore  L. Milano  G. Russo 《Astrophysics and Space Science》1991,183(1):117-127

In this third paper of the series, we analyze five more EB-type eclipsing binaries with short periods (<1 day) and suspected to be contact, or near-contact systems.We find that V747 Cen and ZZ Aur are almost contact systems, RY Ind is a semi-detached system, while AX Vir and ST Car are both detached systems.  相似文献   

New approaches in assessment of tsunami deposits in Dalaman (SW Turkey)     

Bedri Alpar  Selma Ünlü  Yıldız Altınok  Naşide Özer  Abdullah Aksu 《Natural Hazards》2012,60(1):27-41

Some earthquakes in the Eastern Mediterranean are tsunamigenic and some of their tsunamis affected the coastal area of the Gulf of Fethiye, SW Turkey. Recent trenching surveys on the low-lying coastal areas of Dalaman delta beach across the Rhodes Pass revealed three probable tsunami impacts as a result of the historical earthquakes of 1303, 1481 and 1741. Yet, there have been relatively few studies of the processes associated with tsunami sediment transport, their deposition and nature in geological record. In addition to the interpretation of sedimentary features, accurate paleoenvironmental assessments might be possible by distinctive biogeochemical researches on marine-sourced organic matters, geochemical properties, quantitative amounts of marine-sourced biomarkers and deterministic ratios. The identification of major lipid biomarkers (fatty acids and sterols) in the samples recovered from the sidewalls of the studied trench, for example, indicated biogenic contributions due to the presence of phytoplankton, zooplankton, dinoflagellates and bacteria. Quantitative estimation of biomarkers and deterministic ratios also indicated some evidences for marine-sourced organic matters, implying that biomarkers can be used to answer the open questions in tsunami and paleotsunami researches.  相似文献   

The solar flares of August 28 and 30, 1966     

Harold Zirin  D. Russo Lackner 《Solar physics》1969,6(1):86-103

We describe observations of the class 3+ flare of August 28, 1966, made at the Mount Wilson Observatory. This great proton flare followed the sequence: (1) Precursor flare; (2) Filament eruption; (3) Beginning in penumbra of large spot; (4) Rapid elongation in two strands; (5) Great spray and surface wave; (6) Rapid separation of two strands to maximum brightness; and (7) Slow spread of brightness and decay.The soft X-ray burst coincides with stages 3–6, decaying through stage 7; the hard (> 80 keV) burst coincides, but decays more rapidly.Considering a demi-cylinder of emitting material, the soft X-rays are explained by a 4-million-degree plasma, or at least a large flux of electrons with that amount of energy. Given this flux, the microwave burst is explained by synchrotron emission with the low frequency cut-off due to coronal absorption.The class-2 flare of August 30, 1966, is also discussed.This research was supported by the Advanced Research Projects Agency under the Office of Naval Research Grant N00014-67-C-0140 and the National Aeronautics and Space Administration under Grant NGR 05 002 034.NASA International University Fellow at the California Institute of Technology, 1967–1968, now at Arcetri Astrophysical Observatory.  相似文献   

Rainfall stochastic modeling for runoff forecasting     

Fabio Russo  Federico Lombardo  Eugenio Gorgucci 《Physics and Chemistry of the Earth》2006,31(18):1252-1261

Rainfall fields estimation over a catchment area is an important stage in many hydrological applications. In this context, weather radars have several advantages because a single-site can scan a vast area with very high temporal and spatial resolution. The construction of weather radar systems with dual polarization capability allowed progress on radar rainfall estimation and its hydro-meteorological applications. For these applications of radar data it is necessary to remove the ground clutter contamination with an algorithm based on the backscattering signal variance of the differential reflectivity. The calibration of the GDSTM model (Gaussian Displacements Spatial-Temporal Model), a cluster stochastic generation model in continuous space and time, is herewith presented. In this model, storms arrive in a Poisson process in time with cells occurring in each storm that cluster in space and time. The model is calibrated, using data collected by the weather radar Polar 55C located in Rome, inside a square area of 132 × 132 km², with the radar at the centre. The GDSTM is fitted to sequences of radar images with a time interval between the PPIs scans of 5 min. A generalized method of moment procedure is used for parameter estimation. For the validation of the ability of the model to reproduce internal structure of rain event, a geo-morphological rainfall-runoff model, based on width function (WFIUH), was calibrated using simulated and observed data. Several rainfall fields are generated with the stochastic model and later they are used as input of the WFIUH model so that the forecast discharges can be compared to the observed ones.  相似文献   

Geomorphology and landslide susceptibility assessment using GIS and bivariate statistics: a case study in southern Italy   总被引：3，自引：2，他引：1  

Paolo Magliulo  Antonio Di Lisio  Filippo Russo  Antonio Zelano 《Natural Hazards》2008,47(3):411-435

In this article, the results of a study aimed to assess the landslide susceptibility in the Calaggio Torrent basin (Campanian Apennines, southern Italy) are presented. The landslide susceptibility has been assessed using two bivariate-statistics-based methods in a GIS environment. In the first method, widely used in the existing literature, weighting values (Wi) have been calculated for each class of the selected causal factors (lithology, land-use, slope angle and aspect) taking into account the landslide density (detachment zones + landslide body) within each class. In the second method, which is a modification of the first method, only the landslide detachment zone (LDZ) density has been taken into account to calculate the weighting values. This latter method is probably characterized by a major geomorphological coherence. In fact, differently from the landslide bodies, LDZ must necessarily occur in geoenvironmental classes prone to failure. Thus, the calculated Wi seem to be more reliable in estimating the propensity of a given class to generate failure. The thematic maps have been reclassified on the basis of the calculated Wi and then overlaid, with the purpose to produce landslide susceptibility maps. The used methods converge both in indicating that most part of the study area is characterized by a high–very high landslide susceptibility and in the location and extent of the low-susceptible areas. However, an increase of both the high–very high and moderate–high susceptible areas occurs in using the second method. Both the produced susceptibility maps have been compared with the geomorphological map, highlighting an excellent coherence which is higher using method-2. In both methods, the percentage of each susceptibility class affected by landslides increases with the degree of susceptibility, as expected. However, the percentage at issue in the lowest susceptibility class obtained using method-2, even if low, is higher than that obtained using method-1. This suggests that method-2, notwithstanding its major geomorphological coherence, probably still needs further refinements.  相似文献   

Geochemistry and argon thermochronology of the Variscan Sila Batholith,southern Italy: source rocks and magma evolution     

Robert A. Ayuso  Antonia Messina  Benedetto De Vivo  Selma Russo  Laurel G. Woodruff  John F. Sutter  Harvey E. Belkin 《Contributions to Mineralogy and Petrology》1994,117(1):87-109

The Sila batholith is the largest granitic massif in the Calabria-Peloritan Arc of southern Italy, consisting of syn to post-tectonic, calc-alkaline and metaluminous tonalite to granodiorite, and post-tectonic, peraluminous and strongly peraluminous, two-mica±cordierite±Al silicate granodiorite to leucomonzogranite. Mineral ⁴⁰Ar/³⁹Ar thermochronologic analyses document Variscan emplacement and cooling of the intrusives (293–289 Ma). SiO₂ content in the granitic rocks ranges from 57 to 77 wt%; cumulate gabbro enclaves have SiO₂ as low as 42%. Variations in absolute abundances and ratios involving Hf, Ta, Th, Rb, and the REE, among others, identify genetically linked groups of granitic rocks in the batholith: (1) syn-tectonic biotite±amphibole-bearing tonalites to granodiorites, (2) post-tectonic two-mica±Al-silicate-bearing granodiorites to leucomonzogranites, and (3) post-tectonic biotite±hornblende tonalites to granodiorites. Chondrite-normalized REE patterns display variable values of Ce/Yb (up to 300) and generally small negative Eu anomalies. Degree of REE fractionation depends on whether the intrusives are syn- or post-tectonic, and on their mineralogy. High and variable values of Rb/Y (0.40–4.5), Th/Sm (0.1–3.6), Th/Ta (0–70), Ba/Nb (1–150), and Ba/Ta (50–2100), as well as low values of Nb/U (2–28) and La/Th (1–10) are consistent with a predominant and heterogeneous crustal contribution to the batholith. Whole rock ¹⁸O ranges from +8.2 to +11.7; the mafic cumulate enclaves have the lowest ¹⁸O values and the two-mica granites have the highest values. ¹⁸O values for biotite±honblende tonalitic and granodioritic rocks (9.1 to 10.8) overlap the values of the mafic enclaves and two-mica granodiorites and leucogranites (10.7 to 11.7). The initial Pb isotopic range of the granitic rocks (²⁰⁶Pb/²⁰⁴Pb 18.17–18.45, ²⁰⁷Pb/²⁰⁴Pb 15.58–15.77, ²⁰⁸Pb/²⁰⁴Pb 38.20–38.76) also indicates the predominance of a crustal source. Although the granitic groups cannot be uniquely distinguished on the basis of their Pb isotope compositions most of the post-tectonic tonalites to granodiorites as well as two-mica granites are somewhat less radiogenic than the syn-tetonic tonalites and granodiorites. Only a few of the mafic enclaves overlap the Pb isotope field of the granitic rocks and are consistent with a cogenetic origin. The Sila batholith was generated by mixing of material derived from at least two sources, mantle-derived and crustal, during the closing stages of plate collision and post-collision. The batholith ultimately owes its origin to the evolution of earlier, more mafic parental magmas, and to complex intractions of the fractionating mafic magmas with the crust. Hybrid rocks produced by mixing evolved primarily by crystal fractionation although a simple fractionation model cannot link all the granitic rocks, or explain the entire spectrum of compositions within each group of granites. Petrographic and geochemical features characterizing the Sila batholith have direct counterparts in all other granitic massifs in the Calabrian-Peloritan Arc. This implies that magmatic events in the Calabrian-Peloritan Arc produced a similar spectrum of granitic compositions and resulted in a distinctive type of granite magmatism consisting of coeval, mixed, strongly peraluminous and metaluminous granitic magmas.  相似文献   

Temporal changes in fish community structure near a sewage ocean outfall,Mokapu, Oahu,Hawaii     

Anthony R Russo 《Marine environmental research》1982,6(2):83-98

The results of a study performed before and after the discharge of an ocean outfall off Mõkapu Point, Oahu, Hawaii, from 1975 to 1979 show large increases in the number of species and abundance of fish around the outfall site. The construction of the outfall afforded new rock substratum for the attachment of algae and sessile animals which attracted large aggregations of fish. During a $\text{1}\text{1}\text{2}$ year period there were no significant community structure 1–5 km from the outfall when measured by similarity indices. No significant changes in algal biomass occurred between samplings.Similarity indices may be better indicators of fish community change than diversity indices since the former reflect changes in the relative abundance of species in common and large temporal changes in a community structure may occur without changing the value of its diversity index. Morisita's (1959) similarity index has greater sensitivity to the changes in fish community structure than the index derived by Sorensen (1954) due to emphasis on the relative abundance of dominant species.  相似文献   

Biometric and Genetic Analysis of the Marine Rissoid Rissoa auriscalpium (Gastropoda, Prosobranchia) and its Ecological Implications     

Rita  Colognola  Pietro  Masturzo  Giovanni Fulvio  Russo  Mlchele  Scardi  Daniele  Vlnci Eugenio  Fresi 《Marine Ecology》1986,7(3):265-285

Abstract. Two forms of Rissoa auriscalpium were found in Posidonia oceanica beds around the Island of Ischia (Gulf of Naples). In order to investigate their taxonomical value and to quantify the discriminating features found, the radular, conchometric, genetic, and ecological features of the two forms were analyzed. Ecological observations showed that the distribution of the two forms is strongly correlated with hydrodynamic factors.  相似文献