在地球表面的大氣中，受來自太陽高能量光子的解離作用與土壤中的放射性物質對空氣的電離和土壤中釋放的放射性氣體，形成正離子、負離子與電子，使大氣中有少量的電荷可以移動，形成導電率。大氣導電率在不同時間、高度、溫度及濕度等不同大氣組成成分的環境中也會隨之改變。在不同地區量測空氣的導電率，也可以提供空氣汙染程度的資訊。結合大氣電場的量測，可以由導電率推導出在大氣垂直電流密度，電場與電流密度對於探索閃電活動與高層大氣放電中的短暫發光現象都是極為重要的。
在本論文中，將報告我們所設計的導電率量測儀器吉爾定電容器 (Gerdien condenser)，以及所進行的實驗室測試驗證。完成之吉爾定電容器也使用了探空氣球做為載具，送至8公里高度進行飛行實驗，實驗結果也在本論文中報告。未來如果本論文所發展之吉爾定電容器能和電場量測儀一起送到30公里高度的平流層中進行實驗，將可探索台灣附近海洋與陸地上方雷雨雲或對流系統之電氣活動。

In the Earth's atmosphere, positive, negative ions and electrons are weakly dissociated by solar energetic photons, cosmic rays and energetic particles radiated from radioactive substances in the soil. These free charged particles form the atmospheric conductivity. The atmospheric conductivity typically varies with local time, altitude, temperature, humidity and ambient gas composition. The atmospheric conductivity measured in different geographic locations and time can be also used to monitor the air pollution, especially in the vicinity of the metropolitan area. Together with the vertical electric field measurements, we can derive the atmospheric current density which is essential for studies of atmospheric electricity, especially lightning activity and transient luminous events.
In this work, the development and the in-lab test results of a homemade Gerdien condenser for atmospheric conductivity measurements are presented. This Gerdien condenser was also carried by a sounding balloon up to 8 km height, and the experiment results are also demonstrated. This Gerdien condenser is expected to be used in a sounding balloon experiment in the near future, together with electric field instruments, to explore the atmosphere from ground up to the stratosphere region at the height of 30 km and to investigate the electrodynamic processes in the vicinity of thunderstorms and convective systems above land and ocean at Taiwan.

Dhanorkar, S., C. G. Deshpande, and A. K. Kamra (1989), Observations of some atmospheric electrical parameters in the surface layer, Atmospheric Environment, 23, 839-841.
Fang, H. K., K. I. Oyama, and A. B. Chen (2017), Back-diffusion plasma generator for ionosphere study. Plasma Sources Science and Technology, 26(11), 115010.
Gerdien, H. (1905), Nachr. Ges. Wiss. Goettingen, Math.-Phys. Kl., 240.
Gish, O. H. (1994), Evaluation and interpretation of the columnar resistance of the atmosphere, Terr. Magn. Atmos. Elec., 49, 159.
Harrison, R. G. (2004), The global atmospheric electrical circuit and climate. Surveys in Geophysics, 25(5-6), 441-484.
Nicoll, K. A. and R. G. Harrison (2008), Rev. Sci. Instrum., 79, 084502.
Rosen, J. M., D. J. Hofmann, W. Gringel, J. Berlinski, Y. Morita, T. Ogawa and D. Olson(1982), Results of an international workshop on atmospheric electrical measurements, Journal of Geophysical Research, 87, pp. 1219~1224.
Saba, M. M. F., O. pinto Jr., I. R. C. A. pinto and O. Mendes Jr. (2000), Stratospheric balloon measurements of electric fields associated with thunder storms and lightning in Brazil, J. Geophys. Res., 105, pp. 18091~18097.
Rycroft, M. J., and R. G. Harrison (2011), Electromagnetic atmosphere-plasma coupling the global atmospheric electric circuit., Space Sci. Rev., doi: 10.1007/s11214-011-9830-8.
溫少群 (2015), 平流層以下之大氣電場量測, 國立成功大學物理研究所碩士論文。
邱泰瑋 (2017), 使用探空氣球量測對流雲中的電荷垂直分布, 國立成功大學太空與電漿科學研究所碩士論文。