• CHEN ALFRED BING-CHIH (Department of Physics, National Cheng Kung University) ;
  • CHIANG PO-SHIH (Department of Physics, National Cheng Kung University) ;
  • HUANG TIAN-HSIANG (Department of Physics, National Cheng Kung University) ;
  • KUO CHENG-LING (Department of Physics, National Cheng Kung University) ;
  • WANG SHI-CHUN (Department of Physics, National Cheng Kung University) ;
  • SU HAN-TZONG (Department of Physics, National Cheng Kung University) ;
  • HSU RUE-RoN (Department of Physics, National Cheng Kung University) ;
  • CHANG MING-HUI (Department of Automation and Control Engineering, Far East College) ;
  • CHANG YEOU-SHIN (National Space Program Office) ;
  • LIU TIE-YUE (National Space Program Office) ;
  • MENDE STEPHEN B. (Space Science Laboratory, University of California) ;
  • FREY HARALD U. (Space Science Laboratory, University of California) ;
  • FUKUNISHI HIROSHI (Department of Geophysics, Tohoku University)
  • Published : 2005.06.01


Transient luminous events (TLEs; sprites, elves, jets and etc.) are lightning-related optical flashes occurring above thunderstorms. Since the first discovery of sprites in 1989, scientists have learned a great deal about the morphological, spectroscopic and electromagnetic characteristics of TLEs through ground and spacecraft campaigns. However, most of the TLE studies were based on events recorded over US High Plains. To elucidate the possible biasing effects, space-borne observations are needed and have their merits. Imager of sprites and Upper Atmospheric Lightning (ISUAL) on the FORMOSAT-2 satellite is the first instrument to carry out a true global measurement of TLEs from a low- earth orbit. In this short paper, we apply a common astronomical data analysis technique, two-color diagram, on the ISUAL spectrophotometer (SP) data. By choosing appropriated bandpasses and converting the measured flux of TLEs into the unit of magnitude, two-color diagrams of TLEs can be constructed. We demonstrate that two-color diagrams, which were constructed from the narrow-band spectrophotometer data, can be used to classify different types of TLEs and trace their temporal evolution. The amount of reddening due to Earth's atmosphere can also be estimated from two-color diagrams assembled from the broad-band spectrophotometer data.


two-color diagram;methods: data analysis;techniques: photometric


  1. Chern, J. L., Hsu, R. R., Su, H. T., Mende, S. B., Fukunishi, H., Takahashi, & Lee, L. C., 2003, Journal of Atmospheric and Solar-Terrestrial Physics, 65, 647
  2. Franz, R. C., Nemzek, R. J., & Winckler, J. R., 1990, Science, 249, 48
  3. Fukunishi, H., Takahashi, Y., Kubota, M., Sakanoi, K., Inan, U. S., & Lyons, W. A., 1996, Geophys. Res. Lett., 23, 2157
  4. Lyons, W. A., Armstrong, R. A., Williams, E. R.,& Bering, E. A., 2000, EOS, Trans. Amer. Geophy. Union, 81, 373
  5. Su, H. T., Hsu, R. R., Chen, A. B., Wang, Y. C., Hsiao, W. S., Lai, W. C., Lee, L. C., Sato, M., & Fukunishi, H., 2003, Nature, 423, 974
  6. Wescott, E. M., Sentman, D. D., Osborne, D. L., Hampton D. L., & Heavner, M. J., 1995, Geophys. Res. Lett., 22, 1209

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