1,721,077 research outputs found
Estimation of probability of occurrence of F1 layer or L condition using tables and electron density profile models
No full textAn algorithm is proposed for evaluation of the probability of occurrence of an F1 layer or L condition, based on tables. Observations independent of the tables database are used for comparison between the estimated probability of occurrence, the formulation used at present in IRI, and the occurrence actually observed. The importance of the inclusion of L condition in the electron density profile model is shown.Published2053-20563.9. Fisica della magnetosfera, ionosfera e meteorologia spazialeJCR Journalreserve
Electron density profile calculation technique for Autoscala ionogram analysis
No full textAn electron density profile model with free parameters is introduced. Initially the parameters are calculated on the basis of the ionospheric characteristics automatically obtained from the ionograms by Autoscala and considering the helio-
geophysical conditions. The technique used to adjust the free parameters to the particular ionograms recorded is presented.Published756-7661.7. Osservazioni di alta e media atmosfera3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale5.4. Banche dati di geomagnetismo, aeronomia, clima e ambienteJCR Journalreserve
The effect of collisions in ionogram inversion
No full textThe results of this paper demonstrate that the effect of collisions on the group refraction index is small, when the ordinary ray is considered. If, however, in order to improve the performance of a system for automatic interpretation of ionograms, the information contained in ordinary and extraordinary traces is combined, the effect of collisions between the electrons and neutral molecules should be taken into account for the extraordinary ray. The magnitude of these differences is generally very small and must be compared with the resolution in the virtual vertical height of the ionosonde, resolution which is typically of the order of few kilometers.Published697-7011.7. Osservazioni di alta e media atmosfera3.9. Fisica della magnetosfera, ionosfera e meteorologia spazialeJCR Journalrestricte
Sporadi-E layer and metereological activity
No full textObscrvations of Es laycr performed at the ionospheric observatory of Rome from 1982 to 1989 have been used to investigate a possible correlation with cold front passages. Such a correlation may exist because of the AGW excited by tropospheric activity at cold front passages. A relationship with thunderclouds electrostatic field is also marginally considered. The treatment of data shows that the distributions of the frequencies of renection at cold front passages present only small differences compared to normal days, both for the f and for the I type; therefore, a correlation between Es layer anù meteorological activity cannot be affirmed.JCR Journalope
A method for automatic scaling of F1 critical frequencies from ionograms
No full textThis work describes a method that has been developed to automatically assess
whether the F1 layer is present or not on an ionogram trace, and, if present, to scale the
F1 critical frequency foF1. The ionograms in which the information related to the F1 trace
is insufficient are identified and considered separately. In order to test the performance of
this method and the conditions in relation to which it could be improved, a data set of
ionograms recorded from September 2005 to June 2006 by the AIS-INGV ionosonde
installed at Rome was used. The values obtained automatically by Autoscala, with the
addition of this new F1 layer routine, were compared with those obtained by the standard
manual method.PublishedRS2S911.7. Osservazioni di alta e media atmosfera3.9. Fisica della magnetosfera, ionosfera e meteorologia spazialeJCR Journalreserve
Sporadi-E layer and metereological activity
No full textObscrvations of Es laycr performed at the ionospheric observatory of Rome from 1982 to 1989 have been used to investigate a possible correlation with cold front passages. Such a correlation may exist because of the AGW excited by tropospheric activity at cold front passages. A relationship with thunderclouds electrostatic field is also marginally considered. The treatment of data shows that the distributions of the frequencies of renection at cold front passages present only small differences compared to normal days, both for the f and for the I type; therefore, a correlation between Es layer anù meteorological activity cannot be affirmed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Application of Autoscala to ionograms recorded by the VIPIR ionosonde
No full textIn November 2008, the ionosonde station at Boulder, Colorado, USA (40.0°N; 105.3°W) became the host of a new ionosonde
(VIPIR, Vertical Incidence Pulsed Ionospheric Radar) developed and built by Scion Associates.
The VIPIR is a fully digital frequency agile radar that operates between 0.3 and 26 MHz. It features 8 digital receivers and a digital
transmit exciter. Extremely high performance analog receive electronics and a 4 kW solid state amplifier provide interface to the real
world.
This work describes the application of Autoscala to the ionograms recorded by this ionosonde. First results, in terms of ionograms and autoscaled characteristics, are presented and discussed.Published1156-11721.7. Osservazioni di alta e media atmosfera3.9. Fisica della magnetosfera, ionosfera e meteorologia spazialeJCR Journalreserve
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