J/A+A/621/A113 Saturn lightning episodes of storm F (Fischer+, 2019)
Analysis of a long-lived, two-cell lightning storm on Saturn.
Fischer G., Pagaran J.A., Zarka P., Delcroix M., Dyudina U.A., Kurth W.S.,
Gurnett D.A.
<Astron. Astrophys. 621, A113 (2019)>
=2019A&A...621A.113F 2019A&A...621A.113F (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Planets ; Radio sources
Keywords: planets and satellites: atmospheres -
planets and satellites: gaseous planets - methods: data analysis
Abstract:
The paper analyzes a lightning storm on Saturn that raged for 7.5
months at a planetocentric latitude of 35 deg. south from 27 November
2007 until 15 July 2008. The storm system produced about 277000
lightning events termed SEDs (for Saturn Electrostatic Discharges)
that were detected by the Cassini RPWS (Radio and Plasma Wave Science)
instrument. The SEDs are organized in episodes, lasting typically for
half a Saturn rotation. SEDs can be detected when the observer Cassini
is within the radio horizon (usually when the storm and Cassini are on
the same side of the planet), and they are not detected when Cassini
is beyond the radio horizon (Cassini and the storm on opposite sides).
Saturn's atmospheric storm features have a much higher angular
velocity than Cassini around Saturn, so that one SED episode is
typically related to one Saturn rotation. The SEDs from this storm,
lasting from the end of Nov. 2007 until mid-July 2008 (termed storm
F), occurred in 439 SED episodes.
Description:
Table C1 describes basic physical characteristics of 439 regular SED
episodes plus 83 so-called pre- and post-episodes. The 11 columns
denote the episode name, the year, the DOY (day of year) of at the
episode center, the spacecraft event time (hour:minutes) of the
episode's center, the start and stop times of the episode, the number
of detected SEDs, the number of SED pixels (single time- frequency
measurements), the mean distance of Cassini in Saturn radii (RS) to
the 1-bar level of Saturn's atmosphere, the western longitude of the
episode center in degrees (Voyager SLS), and the western longitude at
the beginning and end time of the episode. The letters a and b affixed
to the episode's name in the 1st column denote pre- and post-episodes,
respectively. Pre- and post-episodes are separated in time from the
main episode, but they still belong to the same Saturn rotation and
one of their characteristics is a limited frequency range around 4
MHz. The days of the year in the 2nd column are either from the year
2007 (until F052) or from the year 2008 (starting with F053).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 68 522 Characteristics of 439+83 SED episodes
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Epi Episode name (FNNN)
7- 10 I4 --- Year [2007/2008] Year
12- 14 I3 d Day Day of year (2007/08) of episode center
16- 20 A5 "h:m" TimeC Hour:minute [hh:mm] of episode center
22- 26 A5 "h:m" Dur1 Duration of episode beginning time (in SCET)
27 A1 --- --- [-]
28- 32 A5 "h:m" Dur2 Duration of episode end time ((in SCET)
34- 38 I5 --- NSEDs Number of SEDs in episode
40- 44 I5 --- NPixel Number of SED pixels
46- 50 F5.2 --- Dist Distance of Cassini in Saturn radii (1)
52- 56 F5.1 deg WLC Western longitude SLS of Cassini
at center time of SED episode (2)
58- 62 F5.1 deg WLB Western longitude SLS of Cassini
at beginning of SED episode (2)
64- 68 F5.1 deg WLE Western longitude SLS of Cassini
at end of SED episode (2)
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Note (1): Distance is given in Saturn radii (60268km) from Cassini to center
of Saturn minus 1.
Note (2): SLS is the Voyager Saturn Longitude System.
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Acknowledgements:
Georg Fischer, georg.fischer(at)oeaw.ac.at
(End) Georg Fischer [SRI, OeAW, Austria], Patricia Vannier [CDS] 20-Nov-2018