JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM12] [EE] Space Weather, Space Climate, VarSITI

2017年5月23日(火) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:片岡 龍峰(国立極地研究所)、Antti A Pulkkinen(NASA Goddard Space Flight Center)、草野 完也(名古屋大学宇宙地球環境研究所)、塩川 和夫(名古屋大学宇宙地球環境研究所)

[PEM12-P27] High Intensity Long Duration Continuous Auroral-Electrojet Activity(HILDCAA) in relation to Geomagnetically Induced Current(GIC)

*Krishna Khanal1,2Binod Adhikari1,2Narayan Pd Chapagain1Binod Bhattarai1,2 (1.Tribhuwan University, Nepal、2.St. Xavier's College, Nepal)

キーワード:HILDCAA, GIC, Wavelet Analysis, Cross Correlation

GIC in the buried pipelines during intense geomagnetic storms has long been a subject of research because of its corroding potentiality to the pipeline material accompanied by the production of telluric current. In this work, for the first time, we have analyzed GIC statistics recorded in Finnish Natural Gas pipeline during three HILDCAA events with different interplanetary sources: CIR storm preceded, ICME storm preceded and Isolated. Despite the weak nature of HILDCAAs in terms of Dst reduction, their cumulative contribution in corrosion process is conjectured to be significant as they occur continuously several days to weeks. Analyzing the result, it is found that continuous fluctuation in GIC is observed throughout the AE intensification during all three events, which corresponds to the alfvanic wave fluctuation during HILDCAAs. However, there is no peak to peak relationship between AE index and GIC. Equivalently, every AE intensification does not necessarily account for the higher GIC amplitudes. We have adopted wavelet analysis and cross correlation methods to study the nature of GIC and its possible correlation with other parameters during HILDCAAs. From discrete wavelet transform we analyzed the singularities associated with the discontinuities present in GIC signal up to the three deconposition levels. Similarly, the result of discrete wavelt transform showed spectral variabilities in GIC with different periodicities.