Climatology of ionospheric scintillation over the Vietnam low-latitude region for the period 2006–2014

This paper presents the characteristics of the occurrence of ionospheric scintillations at low-latitude, over Vietnam, by using continuous data of three GSV4004 receivers located at PHUT/Hanoi (105.9 o E, 21.0 o N; magnetic latitude 14.4 o N), HUES/Hue (107.6 o E, 16.5 o N; magnetic latitude 9.5 o N) and HOCM/ Ho Chi Minh city (106.6 o E, 10.8 o N; magnetic latitude 3.3 o N) for the period 2006-2014. The results show that the scintillation activity is maximum during equinox months for all the years and depends on solar activity as expected. The correlations between the monthly percentage scintillation occurrence and the F10.7 flux are of 0.40, 0.52 and 0.67 for PHUT, HUES and HOCM respectively. The distribution of scintillation occurrences is dominant in the pre-midnight sector and around the northern crest of the equatorial ionization anomaly (EIA), from the 15 o N to 20 o N geographic latitude with a maximum at 16 o N. The results obtained from the directional analysis show higher distributions of scintillations in the southern sky of PHUT and in the northern sky of HUES and HOCM, and in the elevation angles smaller than 40 o. The correlation between ROTI and S 4 is low and 2 rather good at PHUT (under EIA) than HOCM (near equator). We found better correlation in the post-midnight hours and less correlation in the pre-midnight hours for all stations. When all satellites are considered during the period of 2009-2011, the range of variation of the ration between ROTI and S 4 is from 1 to 7 for PHUT, from 0.3 to 6 for HUES and from 0.7 to 6 for HOCM.