Abstract. This article aims to explain how Ptolemy could have constructed a map of the Pontus Euxinus (Black Sea), as described in his Geography, under the assumption that his sources were similar to those that have come down to us. The method employed is based on the comparison of Ptolemy's data with corresponding information from other ancient sources, revealing the most conspicuous similarities and differences between them. Three types of information are considered as possible “constituent elements” of Ptolemy's map: latitudes, coastline lengths, and straight-line distances. It is argued that the latitudes Ptolemy used for the key points determining the overall shape of the Pontus (Byzantium, Trapezus, the mouth of the Borysthenes and the Cimmerian Bosporus, the mouth of the Tanais, etc.) were most likely inherited from earlier geographers (Eratosthenes, Hipparchus, and Marinus). In exactly the same way, Ptolemy's data on the circumference of the Pontus and the length of the coastal stretches between the key points (from the Thracian Bosporus to Cape Karambis, Sinope, Trapezus, and the mouth of the Phasis, etc.) closely correlate with the corresponding estimates reported by other geographers (Eratosthenes, Artemidorus, Strabo, Pliny, Arrian, and Pseudo-Arrian), which implies that Ptolemy drew on similar coastline length information. The shortening of Ptolemy's west coast of the Pontus (from the Thracian Bosporus to the mouth of the Borysthenes) relative to the corresponding distances reported by other sources is explained by his underestimation of the circumference of the Earth. The lengthening of Ptolemy's north-east Pontus coast (from the Cimmerian Bosporus to the mouth of the Phasis) can, in part, be accounted for by his attempt to incorporate the straight-line distances across the open sea reported by Pliny. Overall, Ptolemy's configuration of the Black Sea can be satisfactorily explained as a result of fitting contradictory pieces of information together that were inherited from earlier geographical traditions.
{"title":"The configuration of the Pontus Euxinus in Ptolemy's Geography","authors":"Dmitry A. Shcheglov","doi":"10.5194/hgss-11-31-2020","DOIUrl":"https://doi.org/10.5194/hgss-11-31-2020","url":null,"abstract":"Abstract. This article aims to explain how Ptolemy could have constructed a\u0000map of the Pontus Euxinus (Black Sea), as described in his Geography, under the\u0000assumption that his sources were similar to those that have come down to us.\u0000The method employed is based on the comparison of Ptolemy's data with\u0000corresponding information from other ancient sources, revealing the most\u0000conspicuous similarities and differences between them. Three types of\u0000information are considered as possible “constituent elements” of Ptolemy's\u0000map: latitudes, coastline lengths, and straight-line distances. It is argued\u0000that the latitudes Ptolemy used for the key points determining the overall shape of\u0000the Pontus (Byzantium, Trapezus, the mouth of the Borysthenes and the\u0000Cimmerian Bosporus, the mouth of the Tanais, etc.) were most likely\u0000inherited from earlier geographers (Eratosthenes, Hipparchus, and Marinus).\u0000In exactly the same way, Ptolemy's data on the circumference of the Pontus\u0000and the length of the coastal stretches between the key points (from the\u0000Thracian Bosporus to Cape Karambis, Sinope, Trapezus, and the mouth of the\u0000Phasis, etc.) closely correlate with the corresponding estimates reported by\u0000other geographers (Eratosthenes, Artemidorus, Strabo, Pliny, Arrian, and\u0000Pseudo-Arrian), which implies that Ptolemy drew on similar coastline length\u0000information. The shortening of Ptolemy's west coast of the Pontus (from the\u0000Thracian Bosporus to the mouth of the Borysthenes) relative to the\u0000corresponding distances reported by other sources is explained by his\u0000underestimation of the circumference of the Earth. The lengthening of\u0000Ptolemy's north-east Pontus coast (from the Cimmerian Bosporus to the mouth\u0000of the Phasis) can, in part, be accounted for by his attempt to incorporate\u0000the straight-line distances across the open sea reported by Pliny. Overall,\u0000Ptolemy's configuration of the Black Sea can be satisfactorily explained as\u0000a result of fitting contradictory pieces of information together that were inherited\u0000from earlier geographical traditions.","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43733834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The 100th anniversary of the Liverpool Tidal Institute (LTI) was celebrated during 2019. One aspect of tidal science for which the LTI acquired a worldwide reputation was the development and use of tide prediction machines (TPMs). The TPM was invented in the late 19th century, but most of them were made in the first half of the 20th century, up until the time that the advent of digital computers consigned them to museums. This paper describes the basic principles of a TPM, reviews how many were constructed around the world and discusses the method devised by Arthur Doodson at the LTI for the determination of harmonic tidal constants from tide gauge data. These constants were required in order to set up the TPMs for predicting the heights and times of the tides. Although only 3 of the 30-odd TPMs constructed were employed in operational tidal prediction at the LTI, Doodson was responsible for the design and oversight of the manufacture of several others. The paper demonstrates how the UK, and the LTI and Doodson in particular, played a central role in this area of tidal science.
{"title":"Tide prediction machines at the Liverpool Tidal Institute","authors":"P. Woodworth","doi":"10.5194/hgss-11-15-2020","DOIUrl":"https://doi.org/10.5194/hgss-11-15-2020","url":null,"abstract":"Abstract. The 100th anniversary of the Liverpool Tidal Institute (LTI) was\u0000celebrated during 2019. One aspect of tidal science for which the LTI\u0000acquired a worldwide reputation was the development and use of tide\u0000prediction machines (TPMs). The TPM was invented in the late 19th\u0000century, but most of them were made in the first half of the 20th\u0000century, up until the time that the advent of digital computers consigned\u0000them to museums. This paper describes the basic principles of a TPM, reviews\u0000how many were constructed around the world and discusses the method devised\u0000by Arthur Doodson at the LTI for the determination of harmonic tidal\u0000constants from tide gauge data. These constants were required in order to\u0000set up the TPMs for predicting the heights and times of the tides. Although\u0000only 3 of the 30-odd TPMs constructed were employed in operational tidal\u0000prediction at the LTI, Doodson was responsible for the design and oversight\u0000of the manufacture of several others. The paper demonstrates how the UK, and\u0000the LTI and Doodson in particular, played a central role in this area of\u0000tidal science.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47338150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The physician Leonardo Vordoni recorded sea heights at Trieste from 1782 to 1794 because of his interest in studying the connections between tides and the course of diseases that he attributed to the same forces. The data, expressed in Paris feet and inches (1 ft = 12 in. = 32.4845 cm), consist of heights measured on a pole, relative to the green algae belt corresponding to the mean high water. The measurements were reported in a manuscript that was recently found in the correspondence received by Giuseppe Toaldo, an astronomer in Padua. The observations were made twice a day until June 1791 and more frequently afterwards; the data from July 1791 onwards reasonably describe both the astronomical tide and the inverted-barometer (IB) effect. The low frequency of observations and poor metadata information seriously limit the scientific value of the data set, which, therefore, has mainly a historical value. In comparisons with modern data, the amplitude of sea level variations appears rather large, as if a unit shorter than the Paris foot was used. Moreover, an anomalously large decadal trend exists, which might be due to the pole sinking into the sea floor. The sea heights were digitized and are available through SEANOE (SEA scieNtific Open data Edition; https://doi.org/10.17882/62598 ; Raicich, 2019a).
{"title":"A 1782–1794 sea level record at Trieste (northern Adriatic)","authors":"F. Raicich","doi":"10.5194/hgss-11-1-2020","DOIUrl":"https://doi.org/10.5194/hgss-11-1-2020","url":null,"abstract":"Abstract. The physician Leonardo Vordoni recorded sea heights at\u0000Trieste from 1782 to 1794 because of his interest in studying the\u0000connections between tides and the course of diseases that he attributed to\u0000the same forces. The data, expressed in Paris feet and inches (1 ft = 12 in. = 32.4845 cm), consist of\u0000heights measured on a pole, relative to the green algae belt corresponding\u0000to the mean high water. The measurements were reported in a manuscript that\u0000was recently found in the correspondence received by Giuseppe Toaldo, an\u0000astronomer in Padua. The observations were made twice a day until June 1791\u0000and more frequently afterwards; the data from July 1791 onwards reasonably describe both the astronomical tide and the inverted-barometer (IB) effect. The\u0000low frequency of observations and poor metadata information seriously limit\u0000the scientific value of the data set, which, therefore, has mainly a\u0000historical value. In comparisons with modern data, the amplitude of sea\u0000level variations appears rather large, as if a unit shorter than the Paris\u0000foot was used. Moreover, an anomalously large decadal trend exists, which\u0000might be due to the pole sinking into the sea floor. The sea heights were\u0000digitized and are available through SEANOE (SEA scieNtific Open data Edition; https://doi.org/10.17882/62598 ;\u0000Raicich, 2019a).","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141223964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-25DOI: 10.5194/hgss-10-269-2019
Rūta Puzienė
Abstract. The determination of parameters of the Earth's ellipsoid is quite a difficult task that gives no rest to scientists to this day. One of the more famous works is the Struve Geodetic Arc, which was stretched from the Black Sea to the Arctic Ocean by employing the method of a triangulation network and which is included in the UNESCO World Heritage Site list. However, until this project was implemented, many steps of scientific and technological advancement had to be taken, the entirety of which created the conditions for the realization of this project. A study of the method of triangulation measurements, the development of geodetic devices, the state politics of the Russian Empire in the 17th–19th centuries in the field of geodesy, and the development of triangulation during this period are presented in the article. Moreover, a study of the origins of the Struve Geodetic Arc project that led to such a grand result is conducted. The obtained results reveal that certain factors predetermined the favourable conditions for the successful execution of the project of this geodetic arc.
{"title":"The Struve Geodetic Arc: the development of the triangulation, technical possibilities, and the initiation of the project","authors":"Rūta Puzienė","doi":"10.5194/hgss-10-269-2019","DOIUrl":"https://doi.org/10.5194/hgss-10-269-2019","url":null,"abstract":"Abstract. The determination of parameters of the Earth's ellipsoid\u0000is quite a difficult task that gives no rest to scientists to this\u0000day. One of the more famous works is the Struve Geodetic Arc, which was stretched from\u0000the Black Sea to the Arctic Ocean by employing the method of a triangulation\u0000network and which is included in the UNESCO World Heritage Site list. However, until\u0000this project was implemented, many steps of scientific and technological\u0000advancement had to be taken, the entirety of which created the conditions\u0000for the realization of this project. A study of the method of triangulation\u0000measurements, the development of geodetic devices, the state\u0000politics of the Russian Empire in the 17th–19th centuries in the field of\u0000geodesy, and the development of triangulation during this period are\u0000presented in the article. Moreover, a study of the origins of the Struve\u0000Geodetic Arc project that led to such a grand result is conducted. The\u0000obtained results reveal that certain factors predetermined\u0000the favourable conditions for the successful execution of the project of\u0000this geodetic arc.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47321039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-10DOI: 10.5194/hgss-10-267-2019
K. Aplin
{"title":"Book review: Oxford Weather and Climate since 1767 by Stephen Burt and Tim Burt","authors":"K. Aplin","doi":"10.5194/hgss-10-267-2019","DOIUrl":"https://doi.org/10.5194/hgss-10-267-2019","url":null,"abstract":"<jats:p>\u0000 </jats:p>","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42999818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-02DOI: 10.5194/hgss-10-245-2019
R. Woodman, D. T. Farley, B. Balsley, M. Milla
Abstract. The purpose of these historical notes is to present the early history of the Jicamarca Radio Observatory (JRO), a research facility that has been conducting observations and studies of the equatorial ionosphere for more than 50 years. We have limited the scope of these notes to the period of the construction of the observatory and roughly the first decade of its operation. Specifically, this period corresponds to the directorships under Kenneth Bowles, Donald Farley, and Tor Hagfors and the first period of Ronald Woodman, i.e., the years between 1960 and 1974. Within this time frame, we will emphasize observational and instrumental developments which led to define the capabilities of the Jicamarca incoherent scatter (IS) radar to measure the different physical parameters of the ionosphere. At the same time, we partially cover the early history of the IS technique which has been used by many other observatories built since. We will also briefly mention the observatory's early and most important contributions to our understanding of the physical mechanisms behind the many peculiar phenomena that occur at the magnetic Equator. Finally, we will put special emphasis on the important developments of the instrument and its observing techniques that frame the capabilities of the radar at that time.
{"title":"The early history of the Jicamarca Radio Observatory and the incoherent scatter technique","authors":"R. Woodman, D. T. Farley, B. Balsley, M. Milla","doi":"10.5194/hgss-10-245-2019","DOIUrl":"https://doi.org/10.5194/hgss-10-245-2019","url":null,"abstract":"Abstract. The purpose of these historical notes is to present the early history of the Jicamarca Radio Observatory (JRO), a research facility that has been conducting observations and studies of the equatorial ionosphere for more than 50 years. We have limited the scope of these notes to the period of the construction of the observatory and roughly the first decade of its operation. Specifically, this period corresponds to the directorships under Kenneth Bowles, Donald Farley, and Tor Hagfors and the first period of Ronald Woodman, i.e., the years between 1960 and 1974. Within this time frame, we will emphasize observational and instrumental developments which led to define the capabilities of the Jicamarca incoherent scatter (IS) radar to measure the different physical parameters of the ionosphere. At the same time, we partially cover the early history of the IS technique which has been used by many other observatories built since. We will also briefly mention the observatory's early and most important contributions to our understanding of the physical mechanisms behind the many peculiar phenomena that occur at the magnetic Equator. Finally, we will put special emphasis on the important developments of the instrument and its observing techniques that frame the capabilities of the radar at that time.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47893977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-26DOI: 10.5194/hgss-10-235-2019
Nenad Gajić
Abstract. The Gregorian calendar, despite being more precise than the Julian (which now lags 13 d behind Earth), will also lag a day behind nature in this millennium. In 1923, Milutin Milankovitch presented a calendar of outstanding scientific importance and unprecedented astronomical accuracy, which was accepted at the Ecumenical Congress of Eastern Orthodox churches. However, its adoption is still partial in churches and nonexistent in civil states, despite nearly a century without a better proposition of calendar reform in terms of both precision and ease of transition, which are important for acceptance. This article reviews the development of calendars throughout history and presents the case of Milankovitch's, explaining its aims and methodology and why it is sometimes mistakenly identified with the Gregorian because of their long consonance. Religious aspects are briefly covered, explaining the potential of this calendar to unite secular and religious purposes through improving accuracy in both contexts.
{"title":"The curious case of the Milankovitch calendar","authors":"Nenad Gajić","doi":"10.5194/hgss-10-235-2019","DOIUrl":"https://doi.org/10.5194/hgss-10-235-2019","url":null,"abstract":"Abstract. The Gregorian calendar, despite being more precise than\u0000the Julian (which now lags 13 d behind Earth), will also lag a day behind\u0000nature in this millennium. In 1923, Milutin Milankovitch presented a\u0000calendar of outstanding scientific importance and unprecedented astronomical\u0000accuracy, which was accepted at the Ecumenical Congress of Eastern Orthodox\u0000churches. However, its adoption is still partial in churches and nonexistent\u0000in civil states, despite nearly a century without a better proposition of\u0000calendar reform in terms of both precision and ease of transition, which are\u0000important for acceptance. This article reviews the development of calendars\u0000throughout history and presents the case of Milankovitch's, explaining its\u0000aims and methodology and why it is sometimes mistakenly identified with the\u0000Gregorian because of their long consonance. Religious aspects are briefly\u0000covered, explaining the potential of this calendar to unite secular and\u0000religious purposes through improving accuracy in both contexts.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47345454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-29DOI: 10.5194/hgss-10-225-2019
Antonio Lara-Galera, Rubén Galindo-Aires, Gonzalo Guillán-Llorente, Vicente Alcaraz Carrillo de Albornoz
Abstract. Sir Alec Westley Skempton (4 June 1914–9 August 2001) was an English civil engineer and Professor of Soil Mechanics at Imperial College London from 1955 and Head of Department until he retired in 1981. He is often referred to as one of the founding fathers of soil mechanics in the UK and around the world and as one of the most important engineers of the 20th century. Skempton established the soil mechanics course at Imperial College London and not only helped to drive forward understanding of soil behaviours through his research and consultancy work, but also was a reference and inspiration for several engineering generations he taught. He was knighted at the New Year's Honours in 2000 for his services as engineer. He was also a notable contributor to the history of British civil engineering.
{"title":"Contribution to the knowledge of early geotechnics during the 20th century: Alec Westley Skempton","authors":"Antonio Lara-Galera, Rubén Galindo-Aires, Gonzalo Guillán-Llorente, Vicente Alcaraz Carrillo de Albornoz","doi":"10.5194/hgss-10-225-2019","DOIUrl":"https://doi.org/10.5194/hgss-10-225-2019","url":null,"abstract":"Abstract. Sir Alec Westley Skempton (4 June 1914–9 August 2001) was an English\u0000civil engineer and Professor of Soil Mechanics at Imperial College London\u0000from 1955 and Head of Department until he retired in 1981. He is often\u0000referred to as one of the founding fathers of soil mechanics in the UK and\u0000around the world and as one of the most important engineers of the 20th\u0000century. Skempton established the soil mechanics course at Imperial College\u0000London and not only helped to drive forward understanding of soil behaviours\u0000through his research and consultancy work, but also was a reference and\u0000inspiration for several engineering generations he taught. He was knighted at\u0000the New Year's Honours in 2000 for his services as engineer. He was also a\u0000notable contributor to the history of British civil engineering.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48144530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-21DOI: 10.5194/HGSS-10-215-2019
A. Medvedev, A. Potekhin
Abstract. The article focuses on the history of ionospheric research using the incoherent scatter method at the Institute of Solar-Terrestrial Physics and development of the only incoherent scatter radar in Russia, which is located near Irkutsk. It describes the radar features and the current situation of research at the Irkutsk Incoherent Scatter Radar (IISR). Operating modes and types of measurements of the radar are specified. There is a brief description of the original measurement techniques that were developed considering the IISR features such as the frequency principle of scanning and receiving of one linear polarization of a scattered signal. The main feature of the IISR is the possibility of obtaining absolute values of the ionospheric plasma electron density. The automatic method for constructing the electron density vertical profile is based on registration of vertical profiles of a rotation phase of the polarization plane of a scattered signal. The method does not require calibration with additional facilities.
{"title":"Irkutsk Incoherent Scatter Radar: history, present and future","authors":"A. Medvedev, A. Potekhin","doi":"10.5194/HGSS-10-215-2019","DOIUrl":"https://doi.org/10.5194/HGSS-10-215-2019","url":null,"abstract":"Abstract. The article focuses on the history of ionospheric\u0000research using the incoherent scatter method at the Institute of\u0000Solar-Terrestrial Physics and development of the only incoherent scatter\u0000radar in Russia, which is located near Irkutsk. It describes the radar\u0000features and the current situation of research at the Irkutsk Incoherent\u0000Scatter Radar (IISR). Operating modes and types of measurements of the radar are specified. There\u0000is a brief description of the original measurement techniques that were\u0000developed considering the IISR features such as the frequency principle of\u0000scanning and receiving of one linear polarization of a scattered signal. The\u0000main feature of the IISR is the possibility of obtaining absolute values of the\u0000ionospheric plasma electron density. The automatic method for constructing\u0000the electron density vertical profile is based on registration of vertical\u0000profiles of a rotation phase of the polarization plane of a scattered signal. The\u0000method does not require calibration with additional facilities.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44626329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-05DOI: 10.5194/HGSS-10-201-2019
A. Egeland, W. Burke
Abstract. Auroral spectroscopy provided the first tool for remotely sensing the compositions and dynamics of the high-latitude ionosphere. In 1885, Balmer discovered that the visible hydrogen spectrum consists of a series of discrete lines whose wavelengths follow a simple mathematical pattern, which ranks among the first steps toward developing this tool. On 18 October 1939 Lars Vegard discovered the Hα (656.3 nm) and Hβ (486.1 nm) spectral lines of Balmer series emissions, emanating from a diffuse structure, located equatorward of the auroral zone. Intense, first positive bands of N2+ nearly covered the Hα emissions. With more advanced instrumentation after World War II, auroral spectroscopists Vegard, Gartlein and Meinel investigated other characteristics of the auroral hydrogen emissions. The first three lines of the Balmer series, including Hγ at 410 nm, were identified in ground-based measurements prior to the space age. Based on satellite observations, the Balmer lines Hδ and Hε at 410.13 and 396.97 nm, respectively, as well as extreme ultraviolet (EUV) Lyman α (121.6 nm) hydrogen emissions, were also detected. Doppler blue shifts in hydrogen emissions, established in the 1940s, indicated that emitting particles had energies well into the kiloelectron volt range, corresponding to velocities >1000 km s−1. Systematic spatial separations between the locations of electron- and proton-generated aurorae were also established. These observations in turn, suggested that protons, ultimately of solar origin, precipitate into the topside ionosphere, where they undergo charge-exchange events with atmospheric neutrals. Newly generated hydrogen atoms were left in excited states and emitted the observed Balmer radiation. Sounding rocket data showed that most of the hydrogen radiation came from altitudes between 105 and 120 km. Space-age data from satellite-borne sensors made two significant contributions: (1) energetic particle detectors demonstrated the existence of regions in the magnetosphere, conjugate to nightside proton aurora, where conditions for breaking the first adiabatic invariants of kiloelectron volt protons prevail, allowing them to precipitate through filled loss cones. (2) EUV imagers showed that dayside hydrogen emissions appear in response to changes in solar wind dynamic pressure or the polarity of the north–south component of the interplanetary magnetic field.
{"title":"Auroral hydrogen emissions: a historic survey","authors":"A. Egeland, W. Burke","doi":"10.5194/HGSS-10-201-2019","DOIUrl":"https://doi.org/10.5194/HGSS-10-201-2019","url":null,"abstract":"Abstract. Auroral spectroscopy provided the first tool for remotely sensing the\u0000compositions and dynamics of the high-latitude ionosphere. In 1885,\u0000Balmer discovered that the visible hydrogen spectrum consists of a series\u0000of discrete lines whose wavelengths follow a simple mathematical pattern, which\u0000ranks among the first steps toward developing this tool. On 18 October 1939\u0000Lars Vegard discovered the Hα (656.3 nm) and Hβ (486.1 nm) spectral lines of Balmer series emissions, emanating from a diffuse\u0000structure, located equatorward of the auroral zone. Intense, first\u0000positive bands of N2+ nearly covered the Hα emissions. With more advanced instrumentation after World War II, auroral\u0000spectroscopists Vegard, Gartlein and Meinel investigated other\u0000characteristics of the auroral hydrogen emissions. The first three\u0000lines of the Balmer series, including Hγ at 410 nm, were\u0000identified in ground-based measurements prior to the space age. Based on\u0000satellite observations, the Balmer lines Hδ and Hε at 410.13 and 396.97 nm, respectively, as well as extreme ultraviolet (EUV) Lyman\u0000α (121.6 nm) hydrogen emissions, were also detected. Doppler blue shifts in hydrogen emissions, established in the 1940s,\u0000indicated that emitting particles had energies well into the kiloelectron volt range,\u0000corresponding to velocities >1000 km s−1. Systematic spatial\u0000separations between the locations of electron- and proton-generated aurorae\u0000were also established. These observations in turn, suggested that protons,\u0000ultimately of solar origin, precipitate into the topside ionosphere, where\u0000they undergo charge-exchange events with atmospheric neutrals. Newly\u0000generated hydrogen atoms were left in excited states and emitted the\u0000observed Balmer radiation. Sounding rocket data showed that most of the\u0000hydrogen radiation came from altitudes between 105 and 120 km. Space-age data from satellite-borne sensors made two significant\u0000contributions: (1) energetic particle detectors demonstrated the existence\u0000of regions in the magnetosphere, conjugate to nightside proton aurora, where\u0000conditions for breaking the first adiabatic invariants of kiloelectron volt protons\u0000prevail, allowing them to precipitate through filled loss cones. (2) EUV\u0000imagers showed that dayside hydrogen emissions appear in response to changes\u0000in solar wind dynamic pressure or the polarity of the north–south component\u0000of the interplanetary magnetic field.\u0000","PeriodicalId":48918,"journal":{"name":"History of Geo- and Space Sciences","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43116552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"哲学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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