HR: 1340h
AN: AE23A-0988    [Abstracts]
TI: Blue jets, blue starters and other blue luminous events observed by ISUAL payload on the FORMOSAT-2 satellite
AU: * Su, H
EM: htsu@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Hsu, R
EM: rrhsu@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Kuo, C
EM: johnny@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Chen, A B
EM: alfred@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Lee, Y
EM: yjlee@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Chiang, P
EM: poshih@phys.ncku.edu.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Frey, H U
EM: hfrey@apollo.ssl.berkeley.edu
AF: University of California, Space Science Laboratory, University of California, Berkeley, CA 94720 United States
AU: Mende, S B
EM: mende@apollo.ssl.berkeley.edu
AF: University of California, Space Science Laboratory, University of California, Berkeley, CA 94720 United States
AU: Takahashi, Y
EM: yukihiro@pat.geophys.tohoku.ac.jp
AF: Tohoku University, Department of Geophysics, Tohoku University, Sendai, 980-8578 Japan
AU: Fukunishi, H
EM: fuku@pat.geophys.tohoku.ac.jp
AF: Tohoku University, Department of Geophysics, Tohoku University, Sendai, 980-8578 Japan
AU: Lee, L
EM: loulee@narl.org.tw
AF: National Cheng Kung University, Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
AU: Lee, L
EM: loulee@narl.org.tw
AF: National Applied Research Laboratories, National Applied Research Laboratories, Taipei, 10646 Taiwan
AB: Blue jets and blue starters were first discovered in 1994 (Wescott, et. al. GRL, 22, 1209, 1995; GRL, 23, 2153, 1996). During 2000 STEPS campaign, other blue luminous events were also observed to emerge directly from cloud-top and were named gnomes and pixies (Lyons, et. al. BAMS, 445, 2003). The spectroscopic properties of blue starters were investigated in EXL98 campaign and no 2PN2 emission was detected. However using 1NN2+ images at 427.8nm and color TV images, the degree of ionization was estimated to be 3% (Wescott, et. al. JGR, 106, 21549, 2001). Among the thousands of TLEs registered by ISUAL payload onboard the FORMOSAT-2 (Chern et. al. JASTP 65, 647, 2003), more than two hundreds of them were identified as blue luminous events. These events have significant blue channel (370-450nm) signals in the ISUAL array photometer (AP), but have no red channel (530-650nm) emission. In the ISUAL spectrophotometer (SP), they also have strong 2PN2 (337nm) and 1NN2+ (391.4nm) emissions; but only a few also have N2-LBH (150-290nm) or N2 1PG (608.9-753.4nm) emissions and none has SP#5 channel (777.4nm) signal. The AP and SP spectrophometric data indicates that these blue luminous events are not related to lightning. The ISUAL ICCD images, which were taken through the red filter (633-750nm), show that some dim red emissions are emitted from the bottom of these blue luminous events near the cloud-top elevation; for some events the dim red emission can extend for >10km. Based the current spectroscopic information and their luminous duration (<200ms), these events are very similar to the blue jets, blue starters, gnomes or pixies. In this paper, the brightness, the characteristic and average electron energies of these events will be presented. The meteorological conditions for these blue luminous events to occur will also be discussed.
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
DE: 6969 Remote sensing
SC: Atmospheric and Space Electricity [AE]
MN: Fall Meeting 2005