World Library  

Add to Book Shelf
Flag as Inappropriate
Email this Book

D- and E-region Effects in the Auroral Zone During a Moderately Active 24-h Period in July 2005 : Volume 25, Issue 8 (29/08/2007)

By Hargreaves, J. K.

Click here to view

Book Id: WPLBN0004001554
Format Type: PDF Article :
File Size: Pages 13
Reproduction Date: 2015

Title: D- and E-region Effects in the Auroral Zone During a Moderately Active 24-h Period in July 2005 : Volume 25, Issue 8 (29/08/2007)  
Author: Hargreaves, J. K.
Volume: Vol. 25, Issue 8
Language: English
Subject: Science, Annales, Geophysicae
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Publication Date:
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications


APA MLA Chicago

I. Bromag, B. J., Birch, M. J., & Hargreaves, J. K. (2007). D- and E-region Effects in the Auroral Zone During a Moderately Active 24-h Period in July 2005 : Volume 25, Issue 8 (29/08/2007). Retrieved from

Description: Centre for Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK. The effects of energetic electron precipitation into the auroral region at a time of enhanced solar wind have been investigated during a continuous period of 24 h, using the European Incoherent Scatter (EISCAT) radar, an imaging riometer, and particle measurements on an orbiting satellite. The relative effects in the E region (120 km) and D region (90 km) are found to vary during the day, consistent with a gradual hardening of the incoming electron spectrum from pre-midnight to morning. Whereas the night spectra are single peaked, the daytime spectra are found to be double peaked, suggesting the presence of two distinct populations.

A comparison between the radiowave absorption observed with the riometer and values estimated from the radar data shows generally good agreement, but with some discrepancies suggesting the occurrence of some small-scale features. The height and thickness of the absorbing region are estimated. Two periods of enhanced precipitation and the related radio absorption, one near magnetic midnight and one in the early morning, are studied in detail, including their horizontal structure and movement of the absorption patches.

A sharp reduction of electron flux recorded on a POES satellite is related to the edge of an absorption region delineated by the imaging riometer. The observed particle flux is compared with a value deduced from the radar data during the overpass, and found to be in general agreement.

D- and E-region effects in the auroral zone during a moderately active 24-h period in July 2005

Akasofu, S.-I.: The development of the auroral substorm, Planet. Space Sci., 12, 273–282, 1964.; Bogott, F. H. and Mozer, F. S.: Drifting energetic particle bunches observed on ATS 5, J. Geophys. Res., 79, 1825–1830, 1974.; Browne, S., Hargreaves, J. K., and Honory, B.: An imaging riometer for ionospheric studies, Electronics and Communication Engineering Journal, 7, 209–217, 1995.; Burns, C. J., Howarth, W. G., and Hargreaves, J. K.: High-resolution incoherent scatter radar measurements during electron precipitation events, J. Atmos. Terr. Phys., 52, 205–218, 1990.; Collis, P. N., Hargreaves, J. K., and White, G. P.: A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT, Ann. Geophys., 14, 1305–1316, 1996.; Collis, P. N. and Hargreaves, J. K.: Co-ordinated studies using imaging riometer and incoherent scatter radar, J. Atmos. Solar-Terr. Phys., 59, 873–890, 1997.; Detrick, D. L. and Rosenberg, T. J.: A phased-array radiowave imager for studies of cosmic noise absorption, Radio Sci., 25, 325–338, 1990.; Devlin, T., Hargreaves, J. K., and Collis, P. N.: EISCAT observations of the ionospheric D region during auroral radio absorption events, J. Atmos. Terr. Phys., 48, 795–805, 1986.; Evans, D. S. and Greer, M. S.: Polar Orbiting Environmental Satellite Space Environment Monitor – 2: Instrument descriptions and archive data documentation (version 1.4), NOAA Technical Memorandum, 2004.; Gledhill, J. A.: The effective recombination coefficient of electrons in the ionosphere between 50 and 150 km, Radio Sci., 21, 399–408, 1986.; Hairston, M. R. and Heelis, R. A.: Response time of the polar ionosphere convection pattern to changes in the north-south direction of the IMF, Geophys. Res. Lett., 22, 631–634, 1995.; Hargreaves, J. K.: On the variation of auroral radio absorption with geomagnetic activity, Planet. Space Sci., 14, 991–1006, 1966.; Hargreaves, J. K. and Cowley, F. C.: Studies of auroral radio absorption events at three magnetic latitudes. 1. Occurrence and statistical properties of the events, Planet. Space Sci., 15, 1571–1583, 1967.; Hargreaves, J. K.: Auroral absorption of HF radio waves in the ionosphere – a review of results from the first decade of riometery, Proc. IEE 57, 1348–1373, 1969.; Hargreaves, J. K.: Conjugate and closely-spaced observations of auroral radio absorption – IV. The movement of simple features, Planet. Space Sci., 18, 1691–1705, 1970.; Hargreaves, J. K.: Dynamics of auroral absorption in the midnight sector – the movement of absorption peaks in relation to the substorm onset, Planet. Space Sci., 22, 1427–1441, 1974.; Hargreaves, J. K. and Berry, M. G.: The eastward movement of the structure of auroral radio absorption events in the morning sector, Ann. Geophys., 32, 401–406, 1976.; Hargreaves, J. K.: D-region electron densities observed by incoherent-scatter radar during auroral-absorption spike events, J. Atmos. Terr. Phys., 42, 783–789, 1980.; Hargreaves, J. K. and Devlin, T.: Morning sector electron precipitation events observed by incoherent scatter radar, J. Atmos. Terr. Phys., 52, 193–203, 1990.; Hargreaves, J. K.: Substorm effects in the D region. Proc. Third International Conference on Substorms, Versailles, France, May 1996, ESA report SP-389, October 1996.; Hargreaves, J. K., Browne, S., Ranta, H., Ranta, A., Rosenberg, T. J., and Detrick, D. L.: A study of substorm-associated nightside spike events in auroral absorption using imaging riometers at South Pole and Kilpisjärvi, J. Atmos. Solar-Terrestrial Phys., 59, 853–872, 1997.; Hargreaves, J. K.: A new method of studying the relation between ionization rates and radio-wave absorption in polar-cap absorption events, Ann. Geophys., 23, 359–369, 2005.; Hargr


Click To View

Additional Books

  • Hf Doppler Sounder Measurements of the I... (by )
  • Rosetta and Mars Express Observations of... (by )
  • Sunset Transition of Negative Charge in ... (by )
  • Tidal Variations of O2 Atmospheric and O... (by )
  • Waves Off Gopalpur, Northern Bay of Beng... (by )
  • On the Origin of Field-aligned Beams at ... (by )
  • Using Bayesian Model Averaging (Bma) to ... (by )
  • Ion Upflow and Downflow at the Topside I... (by )
  • Multi-instrument Study of Footprints of ... (by )
  • F2-layer Parameters Long-term Trends at ... (by )
  • Diffuse Solar Radiation and Associated M... (by )
  • Concerning Long-term Geomagnetic Variati... (by )
Scroll Left
Scroll Right


Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.