Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007

Abdullah Sabirin, Ahmad Faizal Mohd Zain

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Ionospheric layer plays an important role as the main medium for communication of wireless radio in the High Frequency (HF) band. Critical frequencies are important parameters of the ionosphere. Critical frequencies vary diurnally following the pattern of day and night due to the activities of the sun. The critical frequency for Parit Raja station is determined using an ionosonde at latitude 1° 52' N and longitude 103° 48' E, which are close to the geomagnetic equator at geographic latitude 5° N. This work analyses the dependence of the critical frequency during the solar minimum of Solar Cycle 23. From the observations, the critical frequency observed in 2005 was the highest, corresponding to a higher sunspot number of between 11 and 192. The general trend of the daily critical frequency was 6.8 MHz to 12.0 MHz from 00:00 to 17:30 Coordinated Universal Time (UTC) and decreasing to 7.0 MHz from 18:00 to 23:00 UTC. The average value of the critical frequency for 2005 to 2007 was 7.5 MHz, with a minimum of 1.8 MHz and a maximum of 11.0 MHz. The results showed a slow decrease from 2006 to 2007 for the critical frequencies in 2006 and 2007.

Original languageEnglish
Title of host publicationAEROTECH IV - Recent Advances in Aerospace Technologies
Pages448-452
Number of pages5
Volume225
DOIs
Publication statusPublished - 2012
EventAEROTECH IV - 2012 - Kuala Lumpur
Duration: 21 Nov 201222 Nov 2012

Publication series

NameApplied Mechanics and Materials
Volume225
ISSN (Print)16609336
ISSN (Electronic)16627482

Other

OtherAEROTECH IV - 2012
CityKuala Lumpur
Period21/11/1222/11/12

Fingerprint

Ionosphere
Sun
Frequency bands
Communication

Keywords

  • Critical frequency
  • Equatorial region
  • Ionosphere

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Sabirin, A., & Zain, A. F. M. (2012). Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007. In AEROTECH IV - Recent Advances in Aerospace Technologies (Vol. 225, pp. 448-452). (Applied Mechanics and Materials; Vol. 225). https://doi.org/10.4028/www.scientific.net/AMM.225.448

Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007. / Sabirin, Abdullah; Zain, Ahmad Faizal Mohd.

AEROTECH IV - Recent Advances in Aerospace Technologies. Vol. 225 2012. p. 448-452 (Applied Mechanics and Materials; Vol. 225).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Sabirin, A & Zain, AFM 2012, Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007. in AEROTECH IV - Recent Advances in Aerospace Technologies. vol. 225, Applied Mechanics and Materials, vol. 225, pp. 448-452, AEROTECH IV - 2012, Kuala Lumpur, 21/11/12. https://doi.org/10.4028/www.scientific.net/AMM.225.448
Sabirin A, Zain AFM. Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007. In AEROTECH IV - Recent Advances in Aerospace Technologies. Vol. 225. 2012. p. 448-452. (Applied Mechanics and Materials). https://doi.org/10.4028/www.scientific.net/AMM.225.448
Sabirin, Abdullah ; Zain, Ahmad Faizal Mohd. / Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007. AEROTECH IV - Recent Advances in Aerospace Technologies. Vol. 225 2012. pp. 448-452 (Applied Mechanics and Materials).
@inproceedings{6248f8c2e41949b2aa2dbc86efceef8c,
title = "Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007",
abstract = "Ionospheric layer plays an important role as the main medium for communication of wireless radio in the High Frequency (HF) band. Critical frequencies are important parameters of the ionosphere. Critical frequencies vary diurnally following the pattern of day and night due to the activities of the sun. The critical frequency for Parit Raja station is determined using an ionosonde at latitude 1° 52' N and longitude 103° 48' E, which are close to the geomagnetic equator at geographic latitude 5° N. This work analyses the dependence of the critical frequency during the solar minimum of Solar Cycle 23. From the observations, the critical frequency observed in 2005 was the highest, corresponding to a higher sunspot number of between 11 and 192. The general trend of the daily critical frequency was 6.8 MHz to 12.0 MHz from 00:00 to 17:30 Coordinated Universal Time (UTC) and decreasing to 7.0 MHz from 18:00 to 23:00 UTC. The average value of the critical frequency for 2005 to 2007 was 7.5 MHz, with a minimum of 1.8 MHz and a maximum of 11.0 MHz. The results showed a slow decrease from 2006 to 2007 for the critical frequencies in 2006 and 2007.",
keywords = "Critical frequency, Equatorial region, Ionosphere",
author = "Abdullah Sabirin and Zain, {Ahmad Faizal Mohd}",
year = "2012",
doi = "10.4028/www.scientific.net/AMM.225.448",
language = "English",
isbn = "9783037855065",
volume = "225",
series = "Applied Mechanics and Materials",
pages = "448--452",
booktitle = "AEROTECH IV - Recent Advances in Aerospace Technologies",

}

TY - GEN

T1 - Diurnal and seasonal variation of critical frequency in Malaysia from 2005 to 2007

AU - Sabirin, Abdullah

AU - Zain, Ahmad Faizal Mohd

PY - 2012

Y1 - 2012

N2 - Ionospheric layer plays an important role as the main medium for communication of wireless radio in the High Frequency (HF) band. Critical frequencies are important parameters of the ionosphere. Critical frequencies vary diurnally following the pattern of day and night due to the activities of the sun. The critical frequency for Parit Raja station is determined using an ionosonde at latitude 1° 52' N and longitude 103° 48' E, which are close to the geomagnetic equator at geographic latitude 5° N. This work analyses the dependence of the critical frequency during the solar minimum of Solar Cycle 23. From the observations, the critical frequency observed in 2005 was the highest, corresponding to a higher sunspot number of between 11 and 192. The general trend of the daily critical frequency was 6.8 MHz to 12.0 MHz from 00:00 to 17:30 Coordinated Universal Time (UTC) and decreasing to 7.0 MHz from 18:00 to 23:00 UTC. The average value of the critical frequency for 2005 to 2007 was 7.5 MHz, with a minimum of 1.8 MHz and a maximum of 11.0 MHz. The results showed a slow decrease from 2006 to 2007 for the critical frequencies in 2006 and 2007.

AB - Ionospheric layer plays an important role as the main medium for communication of wireless radio in the High Frequency (HF) band. Critical frequencies are important parameters of the ionosphere. Critical frequencies vary diurnally following the pattern of day and night due to the activities of the sun. The critical frequency for Parit Raja station is determined using an ionosonde at latitude 1° 52' N and longitude 103° 48' E, which are close to the geomagnetic equator at geographic latitude 5° N. This work analyses the dependence of the critical frequency during the solar minimum of Solar Cycle 23. From the observations, the critical frequency observed in 2005 was the highest, corresponding to a higher sunspot number of between 11 and 192. The general trend of the daily critical frequency was 6.8 MHz to 12.0 MHz from 00:00 to 17:30 Coordinated Universal Time (UTC) and decreasing to 7.0 MHz from 18:00 to 23:00 UTC. The average value of the critical frequency for 2005 to 2007 was 7.5 MHz, with a minimum of 1.8 MHz and a maximum of 11.0 MHz. The results showed a slow decrease from 2006 to 2007 for the critical frequencies in 2006 and 2007.

KW - Critical frequency

KW - Equatorial region

KW - Ionosphere

UR - http://www.scopus.com/inward/record.url?scp=84871171446&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84871171446&partnerID=8YFLogxK

U2 - 10.4028/www.scientific.net/AMM.225.448

DO - 10.4028/www.scientific.net/AMM.225.448

M3 - Conference contribution

AN - SCOPUS:84871171446

SN - 9783037855065

VL - 225

T3 - Applied Mechanics and Materials

SP - 448

EP - 452

BT - AEROTECH IV - Recent Advances in Aerospace Technologies

ER -