The Effect of Global Lightning Electric Field on the Ionosphere

• Main Authors: Yi-shin Tasi, 蔡易俽
• Other Authors: Huey-Ching Yeh
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/8fbqn7

碩士 === 國立中央大學 === 太空科學研究所 === 96 === In this thesis, we analyze the data from TRMM LIS and the ROCSAT-1 IPEI payload to investigate the effects of the electric field created by the lightning on the ionosphere. The data are from two periods during 8 November 2000 to 7 February 2001(for northern winter)and 8 May 2001 to 8 August 2001(for northern summer). Based on LIS data, we use the Electromagnetic Pulses model (EMP model) to calculate the electric field generated by the lightning at low altitudes (5~7km), which can reach the bottom-side ionosphere (over 90 km) and discuss the connection between lightning electric fields and ionospheric plasma motions. From TRMM and ROSAT-1 observations, we found two spatially and temporally coincident events, respectively, on 26 January 2001 and 2 February 2001 for detailed analyses. Using lightning emission intensity data of the two events as the input to EMP model, we calculate the magnitude of electric fields that can be transmitted to 200km altitude. The magnitude ranges from 10-3 to 10-4 V/m, which is comparable to that of the electric fields inferred from the IPEI ion drift measurements. In this thesis, we also examine the morphological relationship between lightning occurrence region and the Intertropical Convergence Zone (ITCZ). Both regions are correlated well in the geographic locations and all tend to situate in the summer hemisphere. Moreover, we discuss the lightning occurrence in the regions of South America and South Atlantic Ocean. We find that there is a “lightning hot zone” in the South Atlantic magnetic Anomaly (SAA) region.