ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Some studies on low-frequency signal in relation to X-ray flares and climatic conditions (1994)
    Springer
    Annales geophysicae 12 (1994), S. 1119-1126 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The statistical behaviour of the sudden enhancement in signal strength (SES) in relation to solar X-ray flares has been studied for the near east-west propagation of 40 kHz radio waves from Sanwa (36°11’N; 139°51’E) in Japan to Calcutta (22°34’N; 88°24’E) over a long distance path of 5100 km for a period of two years. The period has been divided into four phases - P1, P2, P3 and P4, according to the position of the overhead sun. The change in signal strength during X-ray flares is dependent on the solar zenith angle and climatic conditions. The statistical modal values of the time lag of the SES peak with respect to that solar X-ray flare is found to increase as solar zenith angle increases. The relative rates of increase and decrease of the signal strength (RRISS and RRDSS respectively) have been evaluated for a number of SES which are related to large X-ray flares. Their characteristics have also been investigated. The modal values of the relaxation time have been found to be highly correlated with climatic conditions like temperature and humidity of the propagation path.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-994-1119-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Anomalous enhancement in daytime 40-kHz signal amplitude accompanied by geomagnetic storms, earthquakes and meteor showers (1995)
    Springer
    Annales geophysicae 13 (1995), S. 1117-1123 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Anomalous propagational characteristics, daytime signal levels greater than night-time, were observed. The amplitude records of a 40-kHz signal propagated over a distance of 5100 km from Sanwa, Japan to Calcutta along a low-latitude path show higher signal strength at midday compared to the midnight level on days preceded by principal geomagnetic storms, earthquakes and major meteor showers. This is explained by the increased ionization in the D-region following geophysical events. The storm after-effects only have a duration of a single day in this low-latitude path.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-995-1117-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Meteorological effect on long distant 40 kHz signal (1985)
    Springer
    Meteorology and atmospheric physics 33 (1985), S. 365-379 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Die vorliegende Arbeit beschäftigt sich mit der Übertragung eines 40 kHz Signals auf langer Distanz, ungefähr von Osten nach Westen. Die Übertragungsstrecke betrug 5100 km und reichte von Sanwa in Japan bis nach Kalkutta in Indien. Dabei wurden Beobachtungen vom April 1981 bis März 1983 ausgewertet und neben den ionosphärisehen Effekten auch die jahreszeitlichen Schwankungen der Amplitude des empfangenen Signals sorgfältig untersucht. Der Amplitudenschwund zu Sonnenaufgang bleibt klar gegenüber dem ionosphärischen Sonnenaufgang zurück und ist einer jahreszeitlichen Variation unterworfen. Entlang des Ausbreitungsweges, der annähernd dem nördlichen Wendekreis folgt, sind die meteorologischen Jahreszeiten durch die Vormonsunperiode (März–Juni), durch den Monsun (Juli–September), der Nachmonsunperiode (Oktober–November) und durch den Winter geprägt. Die meteorologischen Parameter dieser Jahreszeiten drücken den Signalamplituden ihren Stempel auf. Diese sind bemerkenswert gut mit dem Produkt aus der Temperatur und relativer Feuchte korreliert, was auf die endliche Leitfähigkeit der feuchten Luft zurückzuführen ist, die die Dämpfung der Langwellen während ihrer multiplen Wege durch die Troposphäre kontrolliert.
    Notes: Summary Studies have been made over a two-year period from April 1981 to March 1983 on an approximately east-west propagation of a long distant (5100 km) radio wave at 40 kHz from Sanwa, Japan to Calcutta. Besides ionospheric effects, the seasonal variations of the amplitude of the received signal have been carefully examined in this paper. The regular amplitude of the signal shows that the sunrise fade minimum lags well behind the ionospheric sunrise and it varies from season to season. Along the path of propagation which is very close to the tropic of cancer, the four important meteorological seasons are pre-monsoon (March–June), monsoon (July–September), post-monsoon (October–November) and winter (December–February), and the meteorological parameters of these seasons have been found to impress the signal amplitude. The signal amplitude has been found to be remarkably related to the product of the temperature and relative humidity. The correlation lies on the fact that humid air possesses a finite conductivity which controls the attenuation of the long wave while passing through the tropospheric regions in multiple paths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02258486
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Effects of geomagnetic storms on the sunrise fade of long distance 40 kHz signals (1986)
    Springer
    Meteorology and atmospheric physics 35 (1986), S. 227-235 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Das Schwinden von niederfrequenten 40 kHz-Signalen bei Sonnenaufgang wurde an Signalen, die über die große Distanz von 5100 km von Sanwa in Japan nach Kalkutta in Indien übertragen wurden, unter Verwendung der aufgenommenen Daten vom April 1981 bis März 1983, in Beziehung auf vorherrschende geomagnetische Stürme, kritisch untersucht. Die Schwindungsmuster zeigen drei unterschiedliche Typen: bei einem erfolgt die Abnahme in Stufen, beim zweiten zeigt sich eine Abnahme ohne Stufen und der dritte zeigt keine deutliche Abnahme. Der letzte Typ steht deutlich in Zusammenhang mit geomagnetischen Stürmen. Dieser Zusammenhang ist beim zweiten Typ weniger stark ausgeprägt und beim ersten ziemlich klein. Es wurde entdeckt, daß das Ausmaß des Schwindens bei Sonnenaufgang und die Geschwindigkeit des Schwindens vom Zenitwinkel der Sonne abhängig ist. Darüber hinaus wurde entdeckt, daß das Ausmaß des Schwindens mit Zunahme der Sonnenfleckenzahl zunimmt.
    Notes: Summary The sunrise fade of low frequency 40 kHz signals transmitted over a long distance path of 5100 km from Sanwa, Japan to Calcutta, India, was studied critically using the recorded data from April 1981 to March 1983 in relation to principal geomagnetic storms. The fade patterns exhibit three distinct types, one in which the decrease is in steps, a second one showing a decrease without steps, and a third one without significant decrease. The last type is significantly associated with principal geomagnetic storms. The association of the second one with principal geomagnetic storms is moderate, while that of the first one is fairly small. The magnitude of the sunrise fade and time-rate of fade have been found to depend on the solar zenith angle. Moreover, the fade magnitude is found to increase with increasing sunspot number.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01041815
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Regular and seasonal behaviour of atmospheric radio noise field strength (ARNFS) over low latitude station calcutta (1996)
    Springer
    Meteorology and atmospheric physics 61 (1996), S. 107-114 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary The electromagnetic radiation of cloud discharge known as atmospheric radio noise field strength (ARNFS) shows a gradual fall from a frequency of 9 kHz to 81 kHz as studied over a period of two years at Calcutta, very close to Bay of Bengal. The main characteristic features of ARNFS at Calcutta are that-(i) ARNFS shows that midday median value is smaller than midnight median value in all months, (ii) level of daily minimum is higher in February and monsoon compared to other seasons, (iii) ‘sunrise effect’ and ‘sunset effect’ are well correlated with local sunrise and sunset times, (iv) the magnitude of ‘sunrise fade’ and ‘sunrise fade rate’ are maximum in April and lowest during winter period, (v) the magnitude of sunset fade is higher in premonsoon and postmonsoon while it is lowest in monsoon, (vi) number of occurrence of both sunrise effect and sunset effect is remark-ably smaller in monsoon. The positions of the sun and of atmospheric sources are jointly the causes of seasonal and diurnal variations. The missing of ‘sunrise effect’ and ‘sunset effect’ are due to local cloud activity and variation of electron density during geomagnetic storms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01029715
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Nighttime fading ofVLF andLF atmospherics in relation to geomagnetic activity (1995)
    Springer
    Meteorology and atmospheric physics 55 (1995), S. 235-242 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary Long-period fading observed in recordings ofVLF andLF atmospherics in meteorologically clear nights exhibits a good correlation with the geomagnetic activity indexA p . The fading phenomenon occurs more frequently in the case of integrated field intensity of atmospherics than in the case of andLF radio signal transmitted from a certain station. The phenomenon has been analyzed for the monsoon and postmonsoon periods separately, and the results have been discussed in relation to the large-scale travelling ionospheric distubances (LS TID). The modal value of fade periods forVLF andLF atmospherics has been found to be about one hour. It is noted that the correlation of the fade amplitude of highttimeVLF andLF atmospherics versus the geomagnetic activity is frequency dependent and increases fromVLF toLF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01029830
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Seasonal Behaviour of the Afternoon Maximum of a Long-Distance 40 kHz Signal (1997)
    Springer
    Studia geophysica et geodaetica 41 (1997), S. 382-390 
    Details
    ISSN: 1573-1626
    Keywords: Ionosphere ; electron density ; geomagnetic storms ; extra-ionization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Abstract The afternoon maximum (AMX) observed in 40 kHz signal strength, propagated over a distance of 5100 km in the low latitudes of the Northern Hemisphere, exhibits an appreciable asymmetric decrease in its time of occurrence about June-July. The time of occurrence of the AMX of this low-latitude E-W propagation follows the sunset lime equation at the centre of the propagation path. A significant test shows a high correlation of the absence of the AMX with geomagnetic storms. The extra-ionizations in the ionospheric D region during geomagnetic storms may lead to the absence of the afternoon maximum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1023311517946
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    facet.materialart.
    Unknown
    The Effect of Recent Venus Transit on Earth’s Atmosphere (2006)
    Details
    Publication Date: 2019-11-04
    Description: Some experiments on June 8, 2004, the day of transit of Venus across the Sun, were undertaken at Kolkata (latitude: 23034 N) to observe effect, if any, of transit of Venus on FWF, ELF and VLF amplitudes. The result shows good correlation between their temporal variations during the transit. The observation was unbelievable as the Venus subtends only 1/32th of the cone subtended by Sun on Earth. This anomaly may be explained on the assumption that the height of Venusian atmosphere with high content of CO2, and nitrogen which absorbs electromagnetic and corpuscular radiations from Sun, depleting the solar radiation reaching the Earth to a considerable extent. As a result, relevant parameters of Earth’s atmosphere are modulated and here we show how these changes are reflected in identical behaviour of fair weather field and ELF and VLF spectra.
    Description: JCR Journal
    Description: open
    Keywords: Venus transit ; effects on atmospheric electric parameters ; 01. Atmosphere::01.01. Atmosphere::01.01.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 1569280 bytes
    Format: application/msword
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    The effect of recent Venus transit on Earth’s atmosphere (2007)
    Details
    Publication Date: 2019-11-04
    Description: Some experiments on June 8, 2004, the day of transit of Venus across the Sun, were undertaken at Kolkata (latitude: 22°34lN) to observe the effect, if any, of transit of Venus on FWF, ELF and VLF amplitudes. The result shows a good correlation between their temporal variations during the transit. The observation was unbelievable as the Venus subtends only 1/32th of the cone subtended by Sun on Earth. This anomaly may be explained on the assumption that the height of Venusian atmosphere with high content of CO2, and nitrogen which absorbs electromagnetic and corpuscular radiations from Sun, depleting the solar radiation reaching the Earth to a considerable extent. As a result, relevant parameters of Earth’s atmosphere are modulated and here we show how these changes are reflected in identical behaviour of fair weather field and ELF and VLF spectra.
    Description: JCR Journal
    Description: open
    Keywords: Venus transit ; effects on atmospheric electric parameters ; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    Isolation of human T-cell lymphotropic virus type 2 from Guaymi Indians in Panama. (1990)
    National Academy of Sciences
    Details
    Publication Date: 1990-11-01
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...