Statistical analysis of the temperature records for the Northern Territory of Australia     

Alberto Boretti 《Theoretical and Applied Climatology》2013,114(3-4):567-573

The Northern Territory of Australia has a unique situation of an extension larger than France and a population of 200,000, with only three meteorology stations open for more than 40 years, Darwin (DW), Alice Springs (AS) and Tennant Creek, and only two of them, DW and AS, providing data over 100 years, and from 500 to more than 1,000 km separating these stations and the stations in the neighbouring states of Australia. Homogenizations of data in between different measuring sites for the same location as well as the way to derive the missed data to complete at least 100 years from the neighbouring locations are analysed in details and the effects on the temperature trends are straightforwardly investigated. Using properly homogenised data over 130 years and a linear fitting, the warming maximum and minimum temperatures are +0.009 and +0.057 °C/10 years for Alice Springs and ?0.025 and 0.064 °C/10 years for Darwin. With the data available, the only option to produce warming trends is to overweight the cold years in the middle of the 1970s and the subsequent return to warmer temperatures. Starting from 1980, to compute trends, there is still a clear warming in Alice Springs, but also clear cooling in Tennant Creek, and a mixed behaviour with warming maximum temperatures and cooling minimum temperatures in Darwin.  相似文献   

The low-luminosity galaxy population in the NGC 5044 Group     

Sergio A. Cellone  Alberto Buzzoni 《Monthly notices of the Royal Astronomical Society》2005,356(1):41-53

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The Villalbeto de la Peña meteorite fall: II. Determination of atmospheric trajectory and orbit     

Josep M. TRIGO‐RODRÍGUEZ  Ji&#x;í BOROVIKA  Pavel SPURNÝ  Jos L. ORTIZ  Jos A. DOCOBO  Alberto J. CASTRO‐TIRADO  Jordi LLORCA 《Meteoritics & planetary science》2006,41(4):505-517

Abstract— The L6 ordinary chondrite Villalbeto de la Peña fall occurred on January 4, 2004, at 16: 46: 45 ± 2 s UTC. The related daylight fireball was witnessed by thousands of people from Spain, Portugal, and southern France, and was also photographed and videotaped from different locations of León and Palencia provinces in Spain. From accurate astrometric calibrations of these records, we have determined the atmospheric trajectory of the meteoroid. The initial fireball velocity, calculated from measurements of 86 video frames, was 16.9 ± 0.4 km/s. The slope of the trajectory was 29.0 ± 0.6° to the horizontal, the recorded velocity during the main fragmentation at a height of 27.9 ± 0.4 km was 14.2 ± 0.2 km/s, and the fireball terminal height was 22.2 ± 0.2 km. The heliocentric orbit of the meteoroid resided in the ecliptic plane (i = 0.0 ± 0.2°), having a perihelion distance of 0.860 ± 0.007 AU and a semimajor axis of 2.3 ± 0.2 AU. Therefore, the meteorite progenitor body came from the Main Belt, like all previous determined meteorite orbits. The Villalbeto de la Peña fireball analysis has provided the ninth known orbit of a meteorite in the solar system.  相似文献   

The F-type asteroids with small inversion angles of polarization     

I.N. Belskaya  Yu.G. Shkuratov  N.M. Shakhovskoy  A. Cellino  A.A. Ovcharenko  V.G. Shevchenko  C. Barbieri 《Icarus》2005,178(1):213-221

UBVRI polarimetric observations carried out in 1997-2004 for the F-type Asteroids 302 Clarissa, 419 Aurelia, 704 Interamnia, and 762 Pulcova (V band only) are presented. Asteroid 419 Aurelia is characterized by a negative polarization branch which is unusual for low-albedo asteroids. Its depth is about 1%, while the inversion angle, close to 14°, reaches the smallest value ever observed for asteroids. This is the first definite example of a minor body exhibiting a considerable decrease of both the depth and width of the negative polarization branch in comparison with polarization properties of other low-albedo bodies, mimicking a behavior previously found in laboratory measurements of extremely dark surfaces. The F-type Asteroids 302 Clarissa and 704 Interamnia are also characterized by unusually small inversion angles compared to other asteroid types, while Asteroid 762 Pulcova seems to have an ordinary negative polarization branch. Laboratory measurements of low-albedo samples and computer simulations of light scattering by particles of irregular shapes were made to interpret observational data. We find that an optical homogeneity of regolith microstructure at scales of the order of visible light wavelengths may be responsible for relatively small values of the depth of the negative polarization branch and of the inversion angle. Peculiar features of the F-type asteroids compared to other taxonomic classes are discussed.  相似文献   

Orbital Elements of 2004 Perseid Meteoroids Perturbed by Jupiter     

Josep Maria Trigo-Rodriguez  Jeremie Vaubaillon  José Luís Ortiz  Alberto Castro-Tirado  Jordi Llorca  Esko Lyytinen  Martin Jelínek  Antonio de Ugarte Postigo  Pablo Santos Sanz  Francisco J. Aceituno Castro  Albert Sánchez Caso  Antonio Bernal González  Juan Pastor Erades  Francisco Ocaña 《Earth, Moon, and Planets》2005,97(3-4):269-278

Jupiter and Saturn produce important gravitational impulses on meteoroids released by comet 109P/Swift-Tuttle. The meteoroids from this comet once released follow retrograde orbits that during their periodic approaches to these planets (within 1.6 and 0.9 A.U., respectively) are impulsed gaining orbital energy. This perturbation effect is translated into a net inward shift in the node of the perturbed meteoroids. Such geometry with Jupiter occurred in 2004 over a meteoroid trail ejected by this comet during the 1862 A.D. return of the comet to perihelion. In order to study the predicted outburst produced by one-revolution meteoroids, the Spanish Photographic Meteor Network (SPMN) performed an extensive campaign. As a part of this observational effort here are presented 10 accurate meteoroid orbits. We discuss their origin by comparing them with the theoretical orbital elements of the dust trails intercepting the Earth during the 2004 Perseid return.  相似文献   

A Very Small Array search for the extended Sunyaev–Zel''dovich effect in the Corona Borealis supercluster     

Ricardo Génova-Santos  José Alberto Rubiño-Martín  Rafael Rebolo †  Kieran Cleary ‡  Rod D. Davies  Richard J. Davis  Clive Dickinson §  Nelson Falcón ‡‡  Keith Grainge  Carlos M. Gutiérrez  Michael P. Hobson  Michael E. Jones ¶  Rüdiger Kneissl &#;  Katy Lancaster  Carmen P. Padilla-Torres  Richard D. E. Saunders  Paul F. Scott  Angela C. Taylor ¶  Robert A. Watson †† 《Monthly notices of the Royal Astronomical Society》2005,363(1):79-92

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What do we mean by ‘uncertainty’? The need for a consistent wording about uncertainty assessment in hydrology     

Alberto Montanari 《水文研究》2007,21(6):841-845

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Catastrophic fragmentation and formation of families: Preliminary results from a new numerical model     

Paolo Paolicchi  Andrea Verlicchi  Alberto Cellino 《Celestial Mechanics and Dynamical Astronomy》1993,57(1-2):49-56

Preliminary results of an improved version of the semiempirical model for catastrophic break up processes developed by Paolicchi et al., (1989) are presented. Among the several changes with respect to the old version, the most important seem to be related to the new treatment of gravitational effects, including self-compression and reaccumulation of fragments. In particular, the new model is able to analyze processes involving both cm-sized objects, like those studied by means of laboratory experiments, as well as much larger bodies, for which self-gravitational effects are dominant; moreover, in this latter case the model seems in principle adequate to describe with the same physics very different phenomena, like the formation of plausible asteroid families and the creation of single, rapidly spinning, objects. This fact, if confirmed by refined analyses, may be of high importance for our general understanding of asteroid collisional evolution.  相似文献   

First results from the Very Small Array – I. Observational methods     

Robert A. Watson  Pedro Carreira  Kieran Cleary  Rod D. Davies  Richard J. Davis  Clive Dickinson  Keith Grainge †  Carlos M. Gutiérrez  Michael P. Hobson  Michael E. Jones  Rüdiger Kneissl  Anthony Lasenby  Klaus Maisinger  Guy G. Pooley  Rafael Rebolo  José Alberto Rubiño-Martin ‡  Ben Rusholme §  Richard D. E. Saunders  Richard Savage  Paul F. Scott  An&#;e Slosar  Pedro J. Sosa Molina  Angela C. Taylor  David Titterington  Elizabeth Waldram  Althea Wilkinson 《Monthly notices of the Royal Astronomical Society》2003,341(4):1057-1065

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Modulation transfer function for solar telescopes and atmospheric turbulence     

Alberto Righini 《Solar physics》1972,25(1):242-251

Results on the structure coefficient of the temperature field present in the low atmosphere are presented. Measurements have been performed during the national Italian expedition for solar site testing in Isola delle Correnti (southern Sicily).Calculations have been carried out to show the effect of the observed thermal properties of the low atmosphere on telescope performances, with various assumptions as the structure at greater heights.  相似文献