Sains Malaysiana 46(6)(2017): 879–885

http://dx.doi.org/10.17576/jsm-2017-4606-06

 

Pengesanan Gelembung Plasma di dalam Lapisan Ionosfera menggunakan Penerima GPS di Asia Tenggara

(Detection of Plasma Bubble in Ionosphere using GPS Receivers in Southeast Asia)

 

SUHAILA M BUHARI¹*, MARDINA ABDULLAH², YUICHI OTSUKA³, TATSUHIRO YOKOYAMA⁴, MICHI NISHIOKA⁴, ALINA MARIE HASBI⁵& TAKUYA TSUGAWA⁴

 

¹Jabatan Fizik, Fakulti Sains, Universiti Teknologi Malaysia, 81310 UTM, Johor Bahru, Johor Darul Takzim, Malaysia

²Pusat Sains Angkasa, Institut Perubahan Iklim, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

 

³Institute for Space-Earth Environmental Research Nagoya University, Japan

 

⁴National Institute of Information and Communications Technology, Japan

 

⁵Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

 

Received: 30 Jun 2016 /Accepted: 10 November 2016

 

ABSTRAK

Lapisan ionosfera berhampiran kawasan khatulistiwa geomagnetik sering terdedah kepada gangguan pada waktu malam yang dikenali sebagai gelembung plasma (PBB). Kehadiran PBB boleh meningkatkan kadar perubahan amplitud dan fasa isyarat radio yang melaluinya dan memberi kesan terhadap sistem komunikasi dan navigasi. PBB biasanya terjadi secara berturutan dengan satu demi satu struktur muncul pada waktu senja. Walau bagaimanapun, waktu dan lokasi kemunculan PBB tidak dapat diramal kerana punca awal pembentukannya masih belum dikenal pasti. Walaupun pelbagai peralatan telah dibangunkan untuk mencerap PBB, namun setiap alat pengukuran dibataskan oleh resolusi ruang dan masa. Dalam kajian ini, struktur PBB dalam dua dimensi (2D) dicerap menggunakan rangkaian penerima GPS dengan kepadatan yang tinggi di Asia Tenggara. Data GPS dikumpulkan daripada 127 stesen penerima dengan jarak sekitar 30 hingga 120 km di antara satu sama lain. Jumlah kandungan elektron (TEC) diperoleh berdasarkan perbezaan antara dua isyarat yang dipancarkan oleh setiap satelit GPS. Kehadiran PBB dikesan menggunakan indeks kadar perubahan TEC (ROTI) bagi semua laluan isyarat dari satelit kepada penerima. Struktur 2D PBB diperoleh dengan mempuratakan data GPS ROTI ke dalam grid bersaiz 0.45o latitud× 0.45^o longitud dan dipetakan pada ketinggian 300 km. Kajian kes pada malam 18 Mac 2011 menunjukkan kemunculan enam struktur PBB yang berturutan pada waktu senja apeks di sepanjang longitud 95^oT hingga 120^oT. Struktur-struktur PBB tersebut muncul dengan jarak di antara 100 hingga 550 km. Jarak kemunculan sturuktur PBB memainkan peranan penting dalam menentukan punca pembentukannya yang dipercayai berbentuk seakan gelombang.

 

Kata kunci: Gelembung plasma; gangguan ionosfera; GPS TEC; GPS ROTI

 

ABSTRACT

The equatorial ionosphere most often shows a nighttime plasma irregularity that is commonly referred as equatorial plasma bubble (PBB). The occurrence of PBB could cause rapid fluctuations in the amplitude and phase of the propagation radio signals and crucial to communication and navigation systems. The PBB normally occur successively where one structure rising after another during the sunset time. However, the onset time and location of the PBB are ubiquitous because the seed of the initial perturbation is not completely understood. Although various observation systems have been developed to capture the EPB, each of the measurement is limited with space and time resolution. This study aims to observe 2D structure of the PBB using high-density GPS receivers in Southeast Asia. GPS data was collected from 127 GPS receivers in Southeast Asia with the spacing distances of 30-120 km from each other. Total electron content (TEC) was derived from the difference between two signals from each GPS satellite. The signature of the PBB was detected using rate of TEC change index (ROTI) for all the available satellites to receiver paths. The 2D structure of the PBB was obtained by averaging GPS ROTI into 0.45^o latitude × 0.45^o longitude grid and projected at 300 km altitude. A case study on the night of 18 Mac 2011 showed the births of six PBB structures during the passage of the solar terminator along the 95^oE to 120^oE longitude. The separation distance between the PBB structures varied from 300 to 600 km. The separation distance between the EPB structures play an important role in determining the source of the seeding mechanism that believed in a form of wavelike structure.

 

Keywords: Equatorial plasma buble; GPS TEC; GPS ROTI; ionospheric irregularities

REFERENCES

Ajith, K.K., Ram, S.T., Yamamoto, M., Yokoyama, T., Gowtam, V.S., Otsuka, Y., Tsugawa, T. & Niranjan, K. 2015. Explicit characteristics of evolutionary-type plasma bubbles observed from equatorial atmosphere radar during the low to moderate solar activity years 2010-2012. Journal of Geophysical Research 120: 1371-1382.

Buhari, S.M., Abdullah, M., Hasbi, A.M., Otsuka, Y., Yokoyama, T., Nishioka, M. & Tsugawa, T. 2014. Continuous generation and two-dimensional structure of equatorial plasma bubbles observed by high-density GPS receivers in Southeast Asia. Journal of Geophysical Research 119(12): 10,569-10,580.

Fukao, S., Yokoyama, T., Tayama, T., Yamamoto, M., Maruyama, T. & Saito, S. 2006. Eastward traverse of equatorial plasma plumes observed with the equatorial atmosphere radar in Indonesia. Annales Geophysicae24: 1411-1418.

Jaafar, O., Sharifah Mastura, S.A. & Sood, A.M. 2009. Land use and deforestation modelling of river catchments in Klang Valley, Malaysia. Sains Malaysiana38(5): 655-664.

Kelley, M. 1989. The Earth's Ionosphere: Plasma Physics and Electrodynamics. San Diego, Carlifornia: Academic Press.

Makela, J.J. & Otsuka, Y. 2011. Overview of nighttime ionospheric instabilities at low- and mid-latitudes: Coupling aspects resultin in structuring at the mesoscale. Space Science Review 168: 419-440.

Makela, J.J., Vadas, S.L., Muryanto, R., Duly, T. & Crowley, G. 2010. Periodic spacing between consecutive equatorial plasma bubbles. Geophysical Research Letter 37: L14103. doi:10.1029/2010GL043968.

Mustapha, M.A., Lihan, T. & Khalid, L.I. 2014. Coral reef and associated habitat mapping using ALOS satellite imagery. Sains Malaysiana43(9): 1363-1371.

Nishioka, M., Saito, A. & Tsugawa, T. 2008. Occurrence characteristics of plasma bubble derived from global ground based gps receiver networks. Journal of Geophysical Research 113: A05301. doi:10.1029/2007JA012605.

Otsuka, Y., Shiokawa, K., Ogawa, T. & Wilkinson, P. 2002. Geomagnetic conjugate observations of equatorial airglow depletions. Geophysical Research Letter 29(15): 43-1 - 43-4). doi:10.1029/2002GL015347.

Ram, S.T., Yamamoto, M., Tsunoda, R.T., Chau, H.D., Hoang, T.L., Damtie, B., Wassaie, M., Yatini, C.Y., Manik, T. & Tsugawa, T. 2014. Characteristics of large-scale wave structure observed from African and Southeast Asian longitudinal sectors. Journal of Geophysical Research 119: 2288-2297.

Saito, S. & Maruyama, T. 2007. Large-scale longitudinal variation in ionospheric height and equatorial spread F occurrences observed by ionosondes. Geophysical Research Letter 34: L16109. doi:10.1029/2007GL030618.

Singh, S., Johnson, F.S. & Power, R.A. 1997. Gravity wave seeding of equatorial plasma bubbles. Journal of Geophysical Research 102(A4): 7399-7410.

Shiokawa, K., Otsuka, Y. & Ogawa, T. 2006. Quasiperiodic southward moving waves in 630-nm airglow images in the equatorial thermosphere. Journal of Geophysical Research 111: A06301. doi:10.1029/2005JA011406.

Suparta, W., Yatim, B. & Ali, M.A.M. 2009. Pemantauan dan pencirian cuaca angkasa di kawasan UKM Bangi, Selangor menggunakan penerima GPS. Sains Malaysiana38(4): 463-471.

Thampi, S.V., Yamamoto, M., Tsunoda, R.T., Otsuka, Y., Tsugawa, T., Uemoto, J. & Ishii, M. 2009. First observations of large-scale wave structure and equatorial spread F using certo radio beacon on the c/nofs satellite. Geophysical Research Letter 36: L18111. doi:10.1029/2009GL039887.

Tsunoda, R.T. 2015. Upwelling: A unit of disturbance in equatorial spread F. Progress in Earth and Planetary Science 2: 9. doi: 10.1186/s40645-015-0038-5.

Vadas, S.L. & Crowley, G. 2010. Sources of the traveling ionospheric disturbances observed by the ionospheric tiddbit sounder near Wallops Island on 30 October 2007. Journal of Geophysical Research 119: A07324. doi:10.1029/2009JA015053.

Woodman, R.F. 2009. Spread F – an old equatorial aeronomy problem finally resolved? Annales Geophysicae27: 1915- 1934.

Yang, S.R. & Yeh, Y.L. 2015. Geologic hazard risk assessment of slopeland villages in Southern Taiwan using remote sensing techniques. Sains Malaysiana44(12): 1677-1683.

Yokoyama, T., Fukao, S. & Yamamoto, M. 2004. Relationship of the onset of equatorial F region irregularities with the sunset terminator observed with the equatorial atmosphere radar. Geophysical Research Letter 3: L24804. doi:10.1029/2004GL021529.

 

 

*Corresponding author; email: suhailamb@utm.my