Global Survey of TLEs from ISUAL onboard the FORMOSAT-2 Satellite

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Global Survey of TLEs from ISUAL onboard the
FORMOSAT-2 Satellite
Workshop on Coupling of Thunderstorms and
Lightning Discharges to Near-Earth Space

23-27 June 2008, University of Corsica, Corte,
France

• Han-Tzong Su
• Department of Physics, National Cheng Kung Univ.,
  Taiwan
• the ISUAL team

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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• Summary

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Collaborators

• National Cheng Kung University, Taiwan (daily
  operation SDDC)
• Rue-Ron Hsu (PI), Han-Tzong Su, Alfred Chen
• (ISUAL website -- http//sprite.phys.ncku.edu.tw/)
  
• Space Science Lab., UC-Berkeley, USA
• Harald U. Frey, Stephen B. Mende
• Tohoku University, Japan
• Yukihiro Takahashi, Hiroshi Fukunishi
• National Central University, Taiwan
• Lou-Chuang Lee, Cheng-Ling Kuo
• National Chiao-Tung University, Taiwan
• Jyh-Long Chern

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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• Summary

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FORMOSAT-2 satellite
Weight 760 Kg, payloads and fuel included ? small satellite
Size and Shape Hexagonal, height 2.4 meters, outer radius approximately 1.6 meters (with solar panels folded)
Orbit Sun-synchronized orbit at altitude of 891km, passes through Taiwan twice daily
Payloads Remote Sensing Instrument (RSI) and Imager of Sprites and Upper Atmospheric Lightning (ISUAL)
Mission life 5 years
Launcher Taurus rocket, height35m, total weight80 tons
Launch date May 21, 2004
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Missions

• Remote sensing
• to take satellite-imaging data for fulfilling
  Taiwan civilian needs -- to monitor the
  environment and resources throughout the Taiwan
  main island, the offshore remote islands, Taiwan
  Strait, and its surrounding ocean
• may obtain similar images over other regions
  under international cooperation agreements

• Transient luminous events survey
• to obtain of the global distribution of TLEs
• to study the dynamical evolutions and
  spectroscopic characteristics of TLEs
• to elucidate the importance of TLEs in the
  Earths environment
• to investigate auroras, nightglows and gravity
  waves

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The ISUAL payload
ICCD imager
Six filters 623 754 nm 758 769 nm 626 633
nm 555 563 nm 425 432 nm 425 890 nm
Array Photometer (AP)
Six bandpasses 150-290nm(FUV) 333.5-341.2nm 387.1-
393.6nm 658.9-753.4nm 773.6-783.4nm 240-400nm(MUV)
Blue (370 - 450 nm) Red (530 - 650 nm)
Spectrophotometer (SP)
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FOVs, parameters and functions of the sensors

• Array photometer
• (0.05/0.1ms) kR

• Imager (programmable exposure time typ. 14/29
  ms kR)

Blue (370 - 450 nm)
Red (530 - 650 nm)
band pass (623 754) exp 29 ms
Filters (nm) 623 754, 758 769, 626 633,
555 563, 425 432, 425 890

• Spectrophotometer (0.1ms) photon flux (ph/cm2/s)

150-290nm (FUV)
333.5-341.2nm
387.1-393.6nm
658.9-753.4nm
773.6-783.4nm
240-400nm (MUV)
Sprite 2004/07/18 213015.316
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ISUAL ground coverage

• Viewing the pre-midnight region
• FOV 20o by 5o, (coverage 2,850,000 km2)

AB (near edge) Limb CD (far edge)
Distance (km) 2310 3190 4130
Lateral (km) 912 1219 (h 223) 1590
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ISUAL ground coverage
Northern summer
30 N
NA region is not observed in summer!
45 S
SAA
Northern winter
SAA
The effective survey area? between 30S and 30 N,
excluding SAA
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ISUAL TLEs
Images spatial resolution 2 km/pixel at the
limb (3190 km)
sprites
2004/10/22 162345.081
gigantic jet
2005/07/13 043640.193
2004/08/07 180122.742
elve
2004/08/07 180122.742
halo
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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• Summary

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Distribution of ISUAL TLEs (raw data)
2004/07/04 2008/06/16
90
We are here.
60
30
0
-30
-60
-90
7769 810 829 19 (land 3 ocean 16)
Elve sprite halo GJ
Over 9400 TLE events 80 elve 20 sprite
halo
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Winter spring TLEs
Sprite halo 96 Elves 331
4-year cumulative TLE events for December-May
30N
EQ
SAA
30S
Sprite halo 27 Elves 94
4-year cumulative TLE events for June-November
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Winter TLEs
30N
EQ
SAA
30S
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Blue jet 20050612/145442
SP
AP Blue (370 - 450 nm) Red (530 - 650 nm)
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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• Summary

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ISUAL occurrence densities of elve and sprite
occurrence density occur / obser time / grid
area (events/yr/km2)

• ISUAL TLE hot zones
• Sprite
• Central Africa
• Japan Sea
• West Atlantic Ocean
• Elve
• Caribbean Sea
• South China Sea
• East Indian Ocean
• Central Pacific Ocean
• West Atlantic Ocean
• Southwest Pacific Ocean

Chen et al., JGR (2008)
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Occurrence density of ISUAL TLEs
(OTD/LIS)
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The derived TLE occurrence rates(2004.07-2007.12)
events/min
Elves Sprite Halo Total
DJF 3.11 0.37 0.31 3.79
MAM 3.02 0.43 0.40 3.85
JJA 3.16 0.36 0.45 3.97
SON 3.27 0.54 0.37 4.18
Mean 3.23 0.5 0.39 4.12
What is the true global occurrence rates? ? What
are the detection efficiency of ISUAL sensor
package? ? Is ISUAL under-sampled the TLEs?
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Initiation CG peak current of elves
simulated
ISUAL Imager
AP
Kuo et al (2007)
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Occurrence of Elves and the CG peak current
Barrington-Leigh and Inan (1999)
Kuo et al (2007)
NLDN
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1
Occurrence rate of elves could be an order higher
than the ISUAL rate.
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Ground-ISUAL coordinated observation
20070522_151119.763 (distance 2500 km)
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ISUAL columniform sprites
20060711_130119.876 (New Zealand winter)
limb
carrot sprites
20070417_151026.936 (Taiwan spring)
20070222_151257.109 (Japan winter 4200 km)
20051215_201224.030 (Iran winter)
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Published global occurrence rates of sprites

• Blanc et al., (2004)
• ISS (3.5-hour observation)
• 280/3.5 events/hour (lighting)?1.33 events/min
• Sato and Fukunishi (2003)
• 216-day ELF data (715,500) and assuming 32.3 of
  CGs will generate sprites
• Global sprite occurrence rate 0.50 events/min
• Yair et al., (2004)
• Space Shuttle (STS-107 mission, 13-orbit video
  data, 51 min. of thunderstorm)
• 0.33 events/min (TLEs)
• 0.13 events/min (Sprites)
• Ignaccolo et al. (2006)
• optical observations with 4-hour of data and
  27-day of radio gelocation
• Planetary rate of sprite 2.8 events/min

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Global occurrence rates of TLEs
events/min
Elves Sprite Halo Total
DJF 3.11 0.37 0.31 3.79
MAM 3.02 0.43 0.40 3.85
JJA 3.16 0.36 0.45 3.97
SON 3.27 0.54 0.37 4.18
mean 3.23 0.5 0.39 4.12
possible rate 32 1 1 35
daily rate 46000 1400 1400 49000
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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• Summary

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Ionization emissions in sprites and elves
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Elevation of electron density at the lower
D-region due to elves

• Electron cloud in elve has a life time L of 2
  minutes
• Rodger et al.,2001 (simulation), Mika et al.,
  2006 (VLF) Cheng et al. 2007 (VLF)
• cylindrical shape (diameter 165 km thickness 10
  km 80 km to 90 km)
• elves produced a free electron density increase
  of 100
• Mende et al., 2005 Cheng et al., 2007
• Fractional Global increase (r 35 elves/min)
• Fractional increase in the Caribbean region
  (7585W, 515N area 1.3x106 km2 rlocal1.5
  event/min)

Chen et al., JGR (2008)
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E-field and electron energies in sprites
Emissions of sprite
? ratio of SP2/SP3
Event SP2/SP3 E/N (Td) e (avg) E/Ek
sprite 20050923/232803.108 13.7 298 - 420 7.1 - 8.9 2.5 - 3.5
Electric field in streamer region is about 2-4
times the local electric breakdown field at the
sprite altitude
Kuo et al., GRL 2005
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Energy precipitation in the upper atmosphere in a
TLE

• Though analyzing 1,415 ISUAL TLE events, for
  sprite, halo, and elve
• spatially averaged brightness are 1.5, 0.3, and
  0.17 MR
• energy deposition is 56.1, 35.7 and 48.5 MJ per
  event (including non-optical-radiative
  emissions)
• After factoring in the global occurrence rates
• the global energy deposition rates in the upper
  atmosphere are 56, 36, and 1700 MJ per minute

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Outline

• ISUAL experiment on the FORMOSAT-2 satellite
• Global Survey of TLEs
• distributions of TLEs
• occurrence rates of TLEs
• Impacts of TLEs on the Earths environment
• on the electron content of lower ionosphere
• on the energy deposition in the upper atmosphere
• ISUAL auroras, nightglows and gravity waves
• Summary

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Observations of Auroral Arcs and Auroral
Substorms
2007/01/15
Quiet time arc
Exposure Duration 1s Exposure Interval
1.4s Filter 557.7nm MCP HV 600 V Trigger Time
2007/01/15 013737014021 UT (004511
004811 MLT)
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(No Transcript)
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CASE 2
2004/08/31

Arc during the recovery phase of a geomagnetic
storm
Exposure Duration 1s Exposure Interval
1.4s Filter 557.7nm MCP HV 500 V Time
2004/08/31 174606 174852 UT (003231
003540 MLT)
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Exposure Duration 1 s Exposure Interval 1.4
s Filter 630.0 nm MCP HV 700 V Time
2006/12/21 082812 083107
UT (221040221330 MLT)
SAT.
FOV
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Brightening Spots on the Arc
Separation distance 56 km
CASE 1 --- Quiet time arc
Separation distance 112 km
CASE 2 --- Arc during disturbed times
Separation distance 173 km
CASE 3 --- Breakup arc
Separation angle 1.6 degree
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Substorm Onset
This substorm event has extremely fast expansion
from 64 degree to 70 degree in about 2 minutes
.
The observed azimuthal structure of the breakup
arc at onset has an azimuthal mode number of
216, which is consistent with 1. Kinetic theory
of ballooning modes Cheng, Zaharia and
Gorelenkov, 2004, which indicated most unstable
mode at X -8 RE with azimuthal mode number m
300. 2. Observation by THEMIS All Sky Imagers
(ASI), which showed azimuthal mode number m 250
in breakup arc
Example Events observed by ASI at Fort Yukon
(m250)
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ISUAL-airglow
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airglow at 100km and 250km
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ISUAL-gravity waves
G-wave recorded by ROCSAT-2s ISUAL at 0003 on
July 14, 2004 (Taiwan Time)
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Summary

• Elve is the most abundant type of TLEs with
  sprite halo as the distant second.
• Distribution of sprites coincides with lightning,
  whereas elves congregate preferentially over
  ocean.
• The derived global TLE rates
• Elves 35 events/minute
• Sprites and halos 1 events/minute
• Elves could elevate the electron content at the
  lower D-region over the elves hot zones by 5,
  and the average global contribution is 1.
• With these TLE rates, the impacts/effects of TLEs
  on the Earths environment could be determined in
  the future with confidence.

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To Professor Umran Inan his LIREX project