Observations Of D-Region Ionosphere Using Tweek Atmospheric At Low Latitude

Syazwana, Mohamad Sukri (2013) Observations Of D-Region Ionosphere Using Tweek Atmospheric At Low Latitude. Project Report. UTeM, Melaka, Malaysia. (Submitted)

	PDF (24 Pages) Observations_Of_D-Region_Ionosphere_Using_Tweek_Atmospheric_At_Low_Latitude.pdf - Submitted Version Download (1MB)
	PDF (Full Text) Observations_Of_D-Region_Ionosphere_Using_Tweek_Atmospheric_At_Low_Latitude.pdf - Submitted Version Restricted to Registered users only Download (4MB)

Abstract

Tweek atmospherics are electromagnetic pulse signals launched by individual lightning discharges with certain frequency dispersion characteristics at D-region ionosphere. The return strokes of lightning discharges are powerful transmitter of electromagnetic energy over a wide electromagnetic spectrum extended from few Hz to few tens of MHz. Tweeks are observed during nighttime to study the characteristic of D-region parameters in low latitude region. Previously, the measurement of tweek facing many problems in term of high cost and limitation of the signal path to propagation Earth-Ionosphere Waveguide (EIWG). The new technology has been developed to overcome this problem by using AWESOME VLF Receiver. This project is to estimate the night-time ionospheric reflection height (h), the D-region equivalent electron density (ne), and tweek propagation distance (d) from the causative lightning discharge at a low-latitude station. This study analyzes the characteristics of tweek between different stations in low and mid-latitudes and the finding will be developing using Graphical User Interface (GUI) in MATLAB. In the present study tweeks recorded during the night of August to September 2010 at low latitude ground station Allahabad (16.49N; 155.34E). Tweeks up to 4rd modes were observed. Total of 1518 tweeks that occur randomly from first mode until forth mode were extracted from the spectrogram and classified according to their harmonic mode numbers. Tweek duration decreases as mode number increases. Moreover, the distribution of tweek mode numbers reveal that the occurrence of tweeks significantly drops as the mode number increases. It is estimated that the ionospheric electron density varies from 22 to 27 el/cm3 at the altitude of 79-91 km during the local night. The maximum tweeks having propagation distance in the Earthionosphere waveguide from source to receiving station varying in the range of 560- 4166 km.

Actions (login required)

View Item