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| Titel |
Nadir Observations of Lightning and TLEs by JEM-GLIMS |
| VerfasserIn |
Mitsuteru Sato, Tomoo Ushio, Takeshi Morimoto, Makoto Suzuki, Atsushi Yamazaki, Masayuki Kikuchi, Yukihiro Takahashi, Umran Inan, Ivan Linscott, Yasuhide Hobara |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075138
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| Zusammenfassung |
| JEM-GLIMS is a space mission to observe lightning and lightning-associated Transient
Luminous Events (TLEs) from the Exposed Facility (EF) of the Japanese Experiment Module
(JEM) at the International Space Station (ISS). The main purpose of this mission is to carry
out the nadir observations of these phenomena and to identify temporal and spatial evolutions
of lightning and TLEs and to clarify the occurrence conditions of TLEs and global occurrence
locations and rates of TLEs.
JEM-GLIMS consists of two optical instruments, two radio receivers, and one
onboard computer. The optical instruments are two CMOS cameras (LSI-1, LSI-2)
and six-channel spectrophotometers (PH1 - PH6). The FOV of LSI is 28.3 deg.
x 28.3 deg., and LSI-1 (LSI-2) equips a 766-832 nm wide band filter (a 762+/-7
nm narrow band filter). Each PH channel equips the optical band-pass filter, and
these photometers measure the N2 1P, N2 2P, N2 LBH, and N2+ 1N emissions of
lightning and TLEs. The radio receivers consist of one VLF receiver (VLFR) and two
sets of VHF receivers (VITF). In order to detect TLE-associated whistler waves,
VLFR employs a nadir-directing monopole antenna and an electronics unit recording
waveform data with a sampling frequency of 100 kHz with 14-bit resolution. VITF
consists of two patch-type antennas separated by 1.5 m and an electronics unit,
and VITF mainly observes VHF pulses in the frequency range of 70-100 MHz
excited by lightning discharges with a sampling frequency of 200 MHz with 8-bit
resolution.
JEM-GIMS was successfully launched and transported to the ISS by the H-II Transfer
Vehicle (HTV) No.3 cargo transporter at the end of July 2012, and was installed at JEM-EF
on August 9. For the period from September 15 to November 12 we have carried out the
initial checkout operation and confirmed that the functions of all the instruments are normal
and that the performance of all the science instruments is identical with that before launch.
Finally, we have started the continuous observations of lightning and TLEs from November
20, 2012. Up to the end of December 2012, JEM-GLIMS has triggered and recorded 221
transient optical events in total, where strong lightning signatures are confirmed in LSI
and PH channels. For some of these events, transient signatures of N2 LBH are
confirmed in the PH1 channel, which strongly implies the occurrence of TLEs. At the
presentation we will report more detailed initial results derived from JEM-GLIMS data. |
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