Characteristics of Upward Lightning Flashes

In addition to the general aims of lightning research such as lightning physics and meteorology, the study of upward lightning is of particular importance in protection of tall objects such as wind turbines and telecommunication towers. It also helps us in better understanding the lightning initiation process and its role in the earth- atmosphere electrical balance. Within this context, this thesis presents an analysis on various aspects of upward lightning discharge (negative, positive, bipolar) using experimental observation and theoretical modeling for better understanding of its initial stage, the propagation of its electromagnetic field along irregular terrain and its interaction with the ionosphere. Our investigation on the superimposed impulsive components of the initial stage of upward negative flashes revealed that they can transfer net negative charges to ground by both M-component and return stroke modes of charge transfer, which can be distinguished by their associated electric field signature. Moreover, we investigated the ability of Lightning Location Systems (LLSs) to locate and detect upward negative flashes. Different aspects of upward negative flashes which might affect the evaluation performance of LLSs were discussed. It is found that LLSs tend to overestimate the peak current values of RS pulses of upward negative flashes. Using full-wave numerical simulation, it is demonstrated that this overestimation is mainly due to electric field enhancement by wave propagation along mountainous terrain around Säntis Tower. Using simultaneous channel-base current and electric field records of upward positive flashes, we observed that two types of pulsations can be distinguished during the course of progression of upward negative leaders which are very similar to ¿Classical PBPs¿ and ¿Narrow PBPs¿ of the initial stage of downward negative leaders suggesting a general similarity between upward and downward negative leaders. We present and discuss current waveforms associated with 13 bipolar flashes recorded at the Säntis Tower during the period from June 2010 to January 2015. We have found two flashes of our data base each characterized by a sequence of two upward leaders of opposite polarity within the same flash, a scenario that has never been reported from previous observations at instrumented towers. The obtained results suggest that the traditional classification of bipolar flashes should be revisited. We present simultaneous channel-base current and wideband electric field waveforms at 380 km distance from the strike point associated with upward flashes initiated from the Säntis Tower. The dataset presented in this study represents, to the best of the Author¿s knowledge, the first simultaneous records of lightning currents and distant fields associated with natural upward flashes featuring ionospheric reflections. The data are used to infer the characteristics of the ionospheric layers. We present a full-wave 2D FDTD analysis of the field propagation including the effect of the ionospheric reflections and the results are compared with the experimental data. Furthermore, we present a novel semi-analytical simplified approach based on the ray tracing concept to estimate radiated electric fields associated with lightning return strokes, taking into account ionospheric reflections

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Aeronautical Engineering, a continuing bibliography with indexes, supplement 173

This bibliography lists 704 reports, articles and other documents introduced into the NASA scientific and technical information system in March 1984

Aeronautical Engineering: A continuing bibliography, 1982 cumulative index

This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (145) through NASA SP-7037 (156) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes

Research Reports: 1989 NASA/ASEE Summer Faculty Fellowship Program

For the twenty-fifth consecutive year, a NASA/ASEE Summer Faculty Fellowship Program was conducted at the Marshall Space Flight Center (MSFC). The basic objectives of the programs are: (1) to further the professional knowledge of qualified engineering and science faculty members; (2) to stimulate an exchange of ideas between participants and NASA; (3) to enrich and refresh the research and teaching activities of the participants' institutions; and (4) to contribute to the research objectives of the NASA Centers. The Faculty Fellows spent ten weeks at MSFC engaged in a research project compatible with their interests and background and worked in collaboration with a NASA/MSFC colleague

Bibliography of Lewis Research Center technical publications announced in 1989

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1989. All the publications were announced in the 1989 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Bibliography of Lewis Research Center technical publications announced in 1988

This bibliography contains abstracts of the technical reports that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1988. Subject, author, and corporate source indexes are also included. All the publications were announced in the 1988 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses