2013/3/13(ANGWIN workshop, T a chikawa)
Observation of the airglow from the ISS by the IMAP mission
*Y. Akiya [1], A. Saito [1], T. Sakanoi [2],
Y. Hozumi [1], A. Yamazaki [3], Y. Otsuka [4]
[1] Graduation School of Science, Kyoto University , [2] PPARC, Tohoku University,
[3] ISAS/JAXA, [4] STE Laboratory, Nagoya University
----- Outline -----
Introduction of the IMAP mission Visible and near-infrared spectrographic imager Samples of airglow observation by VISI Summary
“ISS-IMAP” mission
Ionosphere, Mesosphere, Upper
Imagers of the
atmosphere and Plasmasphere mapping mission from the International Space Station (ISS)
ISS-IMAP mission
Observational imagers were installed on the Exposure Facility of Japanese Experimental Module: August 9th, 2012.
Initial checkout: August and September, 2012
Nominal observations: October, 2012 -
[Pictures: Courtesy of JAXA/NASA]
“ISS-IMAP” mission
Two imagers are set in MCE and observe from the Exposure
EUVI
Facility of Japanese Experiment Module on the ISS.
VISI (Visible and near-infrared spectrographic imager) observes airglow emission with line
VISI
scanning in the nadir direction. EUVI (Extreme ultraviolet imager) observes resonance scattering light from plasma in the upper atmosphere in the limb direction.
[Sakanoi et al., 2011]
[http://eol.jsc.nasa.gov]
Aurora
Airglow
EUVI-FOV
VISI-FOV
Extreme Ultraviolet Imager (EUVI)
Resonant scattering: 83.4 nm (O+), 30.4 nm (He+) Observation in the day side and the night side Limb observation in backward FOV 15 deg. Weight: 19.3 kg, Size: 170 mm X 370 mm X 480 mm
Initial test of
EUVI: Lid close on August 11, 2012
EUVI He+
(September 26, 2012 07:26UT)
Visible and near-infrared spectrographic imager (VISI)
Airglow: O (630 nm), OH (8-3 band around 730 nm), O2 (762 nm) Observation in the night side Nadir direction observation with FOVs pointing 45 degrees forward and 45 degrees backward
Weight: 14.5 kg, Size: 170 mm X 370 mm X 480 mm Several observational mode
ISS moving direction
Forward FOV
Backward FOV
Observational mode of VISI
Calibration mode
Calibration mode
Images are read out without binning. Full frame data are recorded.
Exposure time: 2 - 4 seconds
Spectral mode
Data at three ROIs (ROI = Region of interest) determined in the forward FOV and three ROIs in the backward FOV are recorded.
Exposure time: 1 - 6 seconds Binning: 8, 16, 32 pixels in spatial direction
Peak mode
The peak and background on each spectrum in the ROIs are determined and recorded.
Left: Spectral mode
Right: Peak mode
Exposure time and binning are same as spectral mode.
Averaged intensity of calibration data spectrum
Averaged for 56
400
calibration mode data
[6]
Forward FOV
Backward FOV
taken from August to December, 2012.
300 200
[1] 557.7nm(O) [2] 589.6nm(Na)
[3] 630.0nm(O)
[4] 636.4nm(O) [5] 732.0nm(O+)
[6] 761.9nm(O2)
[7] 777.4nm(O) [8] 844.6nm(O) [9] 864.5nm (O2)
[9]
[1]
[2]
- [3]
- [5]
[7]
[8]
100
0
[4]
- 500
- 700 800 900
600
Wavelength [nm]
Averaged intensity of OH band emissions
Average of 56 calibration mode data taken from August to December, 2012.
70 60
50 40 30 20
Forward FOV
Backward FOV
[6]
[5]
[2][3]
[1]
[4]
[1] 7-1 (560-570nm) [2] 8-2 (590-600nm)
[7]
[8]
[3] 5-0, 9-3 (620-640nm)
[4] 6-1 (650-670nm) [5] 7-2 (690-705nm)
10
0
[6] 8-3, 4-0, 9-4, 5-1 (720-810 nm)
- 500
- 700 800 900
600
Wavelength [nm]
[7] 6-2 (840-860nm) [8] 7-3 (880-900nm)
762-nm Peak mode observation
Observation around 2012/9/25 02:15 UT
762-nm (95 km altitude)
Background
630-nm Peak mode observation
Observation around 2012/9/25 02:15 UT
630-nm (250 km altitude)
Background
Calibration and flattening of observational data
White pixels are already subtracted from the observational data.
1000
Two strong lines are seen in the
800
762-nm forward FOV peak image. These are also seen in background images.
600
The strength of this effect is not uniform in the same observation. Strength is
affected by the intensity of the light passed the optical system.
Coordinate [pixel]
400
0 10 20 30 40 50 60
Summary
ISS-IMAP mission started the observation of the upper atmosphere in August. Nominal observations by VISI and EUVI has been carried out.
VISI observes the airglow in the nadir direction with two field of views. Target is the airglow originated from the atomic oxygen (630-nm wavelength), OH molecules (0-0 band) and oxygen molecules (762- nm wavelength). It is able to observe 557.7-nm emission from the atomic oxygen, Na emission and other OH band emissions in calibration mode observation.
It is needed to subtract noise caused by electric interference and nonuniformity of optical slit. Noise caused from electrical part has same phase and appearance. On the other hand, noise caused from optical part is different in every observation. Calibration of observational data is needed.
Sensitivity between two field-of-views of VISI are slightly different. This is also thought to be caused from the non-uniformity of the slit width.
Ground-based airglow observations
ALOHA-93 campaign FRONT campaign OMTI: Optical Mesosphere Thermosphere Imagers
Another ground-based airglow imager will be put at Hawaii as a part of
Observations of OH airglow by OMTI [Shiokawa et al., 1999]
ISS-IMAP project.
Airglow observation from space shuttle
Observed by GLO-1 during the STS 53 shuttle mission [Broadfoot et al., 1999]
Many observations of the airglow are made by the ground-based imager, rockets and satellites.
Airglow is observed with spectrographic image in the
nadir direction in the ISS-IMAP mission.
Airglow observations by rockets and satellites
Example of rocket observations (Photometer of TOMEX project) are shown in the right figures
TIMED satellite WINDII, HRDI on UARS satellite
ISUAL/FORMOSAT-2 Multi-spectral auroral camera on INDEX (Reimei) satellite
[Hecht et al., 2004]
Airglow observation from space shuttle
Observed by GLO-1 during the STS 53 shuttle mission [Broadfoot et al., 1999]
View of ISS-IMAP instruments in “MCE”
MCE = Multi-mission consolidated equipment
1.8 m x 1.0 m x 0.8 m, 450 kg weight
EUVI(IMAP)
SIMPLE
Five missions (IMAP, GLIMS, SIMPLE, REXJ and HDTV) uses a single port this time.
REXJ
GLIMS
VISI(IMAP)
HDTV
Specification of VISI
Size 450 mm x 240 mm x 210 mm
- Weight
- 14.5 kg
e2V 47-20 back-illuminated AIMO, 1024 x 1024 pixels
1 pixel size = 13.3μm x 13.3μm
CCD sensor
Rectangular shaped
(90 x 0.09 deg)
FOVs pointing 45 degrees forward and 45 degrees backward
Field-ofview
(FOV)
Objective lens
F/0.96, f = 5.5 mm
ISS moving direction
Forward FOV
Spectrosc Wavelength coverage: 600 - opic 800 nm in the both FOVs properties Resolutions ~ 1.0nm / pixel
Backward FOV
Specification data:[Sakanoi et al., 2011]
Observational target of VISI
Atomic oxygen (O) airglow
630-nm wavelength ~ 250 km altitude (F2 layer), ~ 100 kR
OH molecule airglow observes in 730-nm wavelength ~ 87 km altitude, ~ 1kR
Oxygen molecule (O2) airglow
762-nm wavelength ~ 100 km altitude
630-nm emission from atomic oxygen
O(1D) → O(3P2) + hν(630.0nm) O(1D) → O(3P1) + hν(636.4nm) O(1D) → O(3P0) + hν(639.2nm) Intensity of 630.0-nm wavelength emission at night is ~100 kR
The lifetime of the excited state (1D) of the atomic oxygen is ~134 seconds. These atoms radiates at the altitude of ~250 km (~F2 layer).
762-nm emission from oxygen molecule
The emission from oxygen molecule O2(b1Σ+ )
g
→ O2(X3Σ-g) has two intense bands:
761.9-nm, (0-0) band 864.5-nm, (0-1) band
Radiative lifetime of metastable molecules is ~12 seconds. These molecules emit at the altitude in 90 - 100 km. These emissions are usually absorbed by the Earth atmosphere and difficult to observe from the ground.
Hydroxyl emissions
Hydroxyl emission arises in the upper atmosphere at ~87 km altitude. Average intensity of this emission is ~ 1 kR.
(8-3) band is around 730-nm wavelength OH molecules are thought to be produced by the reactions in below. (M = O2 or N2)
The ozone-hydrogen reaction: O + O2 + M → O3 + M H + O3 → OH + O2
The reaction of perhydroxyl with atomic oxygen: H + O2 + M → HO2 + M O + HO2 → OH + O2
Data processing
Camera format data
VISI raw data
Take out observational data
tfb data One file for one raw data file
Separate data into groups for each observations
decoded data One file for one snap shot
Refer the ROM table (Observational mode, Exposure time), sensitivity
Make continuous data file for one observation
Level-1 data
One file for one observation (one mode)
IDL routines q - parameters, transfer to absolute
intensity, FOV angle
plotted data
altitude, attitude
JPEG, FITS, IDL save
Level-2 data “Science” data
Example data of Calibration mode
# Version: 1.0 # Program: visi_level1_make.pro (Ver. 1.0) # Creator: T. Sakanoi
←Version of data ←IDL procedure used ←Data creator
# Create Date: Mon Oct 1 14:43:55 2012
←Created date
# Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI3706_12090509452305_TBL14_0543207_decode.dat # Data File End :
←First decoded data
IMP_EXP_2012-09-05.log_tfb_VISI3706_12090509452305_TBL14_0543207_decode.dat
←Last decoded data
- # Data File Number:
- 1
←Number of shots in the observation
# VISI Table Version: 2012-02-21 # Mode:
←Date of ROM table updated ←Observational mode (No description for CAL mode) ←Binning ←Exposure time ←Exposure time + read out
# Binning Number (a) (pix): # Exposure Time (b) (sec)= # Exposure Cycle (sec)=
32
6.00000
6.58800
# X-pix, Y-Pix, ROI number= 1028 1072 # Unit: Counts in a exposure time
1
←Number of pixels in Spatial, Wavelength and number of ROI ←Physical unit of the data in below
←Sensitivity
←Mode of gain
# Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 # Gain : # Conversion Factor from Count to Electron (e) :
0
←Relation between counts and electrons
1.24000
# NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER
←Number of file is 1 if 0/0 ←Time of observational shot (←This description can be ignored in CAL mode)
File number= Date, UT(hhmmss)= 20120905 094523 O 630nm, Backward,ROI= 5/
- 0/
- 0
6
691 691 690 689 692 689 688 688 688 686 688 691 689 691 684 686 688 686 690 693
←Data are written in below
Example data of Spectral mode
# Version: 1.0 # Program: visi_level1_make.pro (Ver. 1.0) # Creator: T. Sakanoi # Create Date: Mon Oct 1 14:43:44 2012 # Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI0001_12090500212205_TBL01_0003986_decode.dat # Data File End : IMP_EXP_2012-09-05.log_tfb_VISI0001_12090500212205_TBL01_0003986_decode.dat
- # Data File Number:
- 1
# VISI Table Version: 2012-02-21 # Mode: Spectral mode # Binning Number (a) (pix): # Exposure Time (b) (sec)= # Exposure Cycle (sec)= # X-pix, Y-Pix, ROI number=
16
1.00000
1.86200
- 64
- 12
- 6
# Unit: Counts in a exposure time # Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 # Gain : # Conversion Factor from Count to Electron (e) :
0
1.24000
# NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER
←Number of file is 1 if 0/0 ←Time of observational shot ←Source of emission, wavelength, observed FOV, ROI number
File number= Date, UT(hhmmss)= 20120905 002122 O2 762nm, Forward, ROI= 0/
- 0/
- 0
6
521 521 522 530 585 536 3488 556 551 543 539 564 613 532 539 535 544 531 533 535 536 538 699 548 542 550 557 567 567 571 561 561 551 561 561 551 558 558 575 579 583 575 564 558 544 554 539 583 542 540 535 533 535 527 525 533 531 528 525 519 517 521 519 491
←Data are written in below
Example data of Peak mode
# Version: 1.0 # Program: visi_level1_make.pro (Ver. 1.0) # Creator: T. Sakanoi # Create Date: Mon Oct 1 14:43:45 2012 # Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI0002_12090500212505_TBL07_0000981_decode.dat # Data File End : IMP_EXP_2012-09-05.log_tfb_VISI0662_12090500422405_TBL07_0000912_decode.dat
- # Data File Number:
- 661
# VISI Table Version: 2012-02-21 # Mode: Peak mode # Binning Number (a) (pix): # Exposure Time (b) (sec)= # Exposure Cycle (sec)= # X-pix, Y-Pix, ROI number=
16
1.00000
1.86200
- 64
- 2
- 6
# Unit: Counts in a exposure time # Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 # Gain : # Conversion Factor from Count to Electron (e) :
0
1.24000
# NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER
←1st data of 660 data in this observation ←Time of observational shot ←Source of emission, wavelength, observed FOV, ROI number
File number= Date, UT(hhmmss)= 20120905 002125 O2 762nm, Forward, ROI= 0/
- 0/
- 660
6
548 870 861 848 902 959 546 519 537 537 531 532 533 523
551 924 875 872 907 976 548 524 539 540 527 536 539 520
550 910 843 876 935 953 540 523 538 540 533 537 528 515
557 922 843 893 964 928 2489 532 520 535 530 531 539 533 499
628 919 844 891 980
613 871 866 1191 850 979
890
858 861
840 850
860
871 925
791
820 881
850
926 908
554
826 881
846
936 935
548
841 955
892
←Peak data
565 528 527 535 534 528
545 534 535 529 537 526
666 531 529 530 538 537
578 530 537 531 534 528
549 535 531 537 543 520
545 532 534 532 542 520
←Background data
Calibration mode image
2012/8/13 03:25:08 UT Exposure time: 6 seconds Line dispersion: 0.90 nm/pixel in forward FOV, 1.02 nm/pixel in backward FOV
Region for ~600 km is taken in spatial direction
Forward FOV
Wavelength
Backward FOV
Wavelength
Count values on CCD
570 560 550 540
Backward
FOV
Counts shown in the right figure are averaged for 60 pixels in each regions.
Forward
FOV
530
650 850
750
550 650 750
Wavelength [nm]
Wavy structure caused from mechanical part of imager is seen in the backward FOV.