今井卒論 (金星) - 地球惑星科学科 - 北海道大学

Imai Masataka
: 22090112
Department of Earth Science, Undergraduate school of Science,
Hokkaido University
Planetary and Space Group
:
25 4 10

Abstract
,
. ,
.
60 ,
. ,
45–70 km H 2 SO 4 365 nm
,
. (∼1000 km) ,
Y . [Esosito et al., 1997
] Del Genio & Rossow (1982, 1990) ,
, ()
. Pioneer Venus OCPP
, ,
4–6 .
, 1.6m 1, 2
,
.
, 1 8
,
.
,
””
.
, 7 5
365 nm . ,
, .
, ∼5,000 km
.
, 50 ◦ S – 50 ◦ N
. ,
Venus Express VMC ,
,
.

1
1 Introduction 2
1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Observation 11
2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3 Data Reduction & Analysis 16
3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 1 : . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 2 : . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4 Results 26
5 Discussion 34
6 Summary & Future Work 36
7 Appendix 38
8 Acknowledgments 45
9 References 46
2013/04/10( )

1 Introduction 2
1 Introduction
1.1
,
. , Table 1.1
. , 96 CO 2
, 45–70 km H 2 SO 4 .
.
, . 1.3
.
, 3 ◦
.
,
.
[km] 6052 6378
[10 24 kg] 4.87 5.97
[g/m 3 ] 5.24 5.52
[m/s 2 ] 8.9 9.8
[AU] 0.723 1.00
0.00677 0.01671
3.39 ◦ 0 ◦
177.4 ◦ 23.44 ◦
() 243.0 1.00
() 224.7 365.2
[hPa] 92000 1013
[K] 730 288
Table 1.1: (, 2011 )
2013/04/10( )

1 Introduction 3
1.2
Pioneer Venus OCPP (Orbiter Cloud Photopolarimeter)
.
,
Y .
283 nm 365 nm , SO 2 . SO 2
, 283nm
.
, . S
, . 365 nm
,
365 nm .
.
[Pollack et al., 1980; Toon et al., 1982; Esposito, 1980]
Figure 1.1: OCPP A : March 3,1979, B : March 7,1979, C : March 9,1979
(Rossow et al, 1980)
OCPP 1979 4 . A
B , C A,B .
Y .
1.3 Figuge 1.1 A
B 4 1 , C B 2
, .
Y 4 .
2013/04/10( )

1 Introduction 4
OCPP
. Y 50 ◦ ,
.
Figure 1.2: : 20 ◦ 50 ◦ (Rossow
et al, 1980)
2013/04/10( )

1 Introduction 5
1.3
Y , 1960
4
. 6,050 km ,
100 m/s .
243 , 1.6 m/s .
60 . ,
.
, ”
””4 ”.
, . Figure 1.3 (a)
. 60
. ,
. Figure 1.3 (b) Glileo 418 nm 986 nm
418 nm(•) 65–70 km
, 986 nm(×) .
,
, .
(a) (b) Galileo
(Schubert, 1983)
(Peralta, 2007)
Figure 1.3:
2013/04/10( )

1 Introduction 6
1.4
Y ,
.
Del Genio & Rossow (1982, 1990) , Pioneer Venus OCPP
. Figure 1.4 45 ◦ 2 , 90 ◦
. 4
. 4
, . ,
45 ◦ .
Figure 1.4: Pioneer Venus OCPP (Del Genio &
Rossow, 1982)
,
. (Figure 1.5, 1.6) OCPP
1979 1986 8 , ∼1
.
, .
.
2013/04/10( )

1 Introduction 7
Figure 1.5: 1 (Del
Genio & Rossow, 1990)
2013/04/10( )

1 Introduction 8
Figure 1.6: 2 (Del
Genio & Rossow, 1990)
2013/04/10( )

1 Introduction 9
() (◦ : Brightness) ,
OCPP (• : Mean Zonal Wind)
. 200–600 km
. [Rossow et al, 1989]
.
, 5–10
.
Figure 1.7: (Del Genio & Rossow, 1990)
2013/04/10( )

1 Introduction 10
1.5
,
. Del Genio & Rossow (1990) OCPP
, , ,
.
() . Figure 1.7
5–10 , ( 243.0 ,
224.7 , 1 116.8 )
.
,
, .
.
, (,
) . ,
.
2012 7
, . ,
.
2013/04/10( )

2 Observation 11
2 Observation
2.1
○
1.6 m
.
, .
. 2.3 .
220 km , 142 ◦ 28 59 ,
44 ◦ 22 27 , 161 , 1.3–2.3
arcsec . .
1600 mm
19238 mm (F/12.0)
20
Table 2.1:
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2 Observation 12
Figure 2.1:
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2 Observation 13
○MSI(Multi -Spectral Imager)
MSI (Multi -Spectral Imager) ,
.
,
. EM -CCD ,
,
.
Figure 2.2: MSI
• × 2
•
•
0.36–1.05 m
3.3 ×3.3 (0.39 /pixel)
VIS: 400–720nm, ∆λ ∼10nm (@650nm)
SNIR: 650–1100nm, ∆λ ∼10nm (@900nm)
360, 365, 370, 380, & 390nm, ∆λ=10nm
B, V, Rc, Ic
512×512 pixel EM -CCD ()
B∼19.8, V∼19.8, R∼19.6, I∼18.6 (60s , S/N=10)
Table 2.2: MSI
2013/04/10( )

2 Observation 14
2.2
,
.
, . --
. MSI
. 1 ∼ 8 .
. (→ Analyze)
Dataset , 1 8 ,
1,2. 2012/6/6 ()
, 2013/3/29
,
(×10) → (×3) →
360 nm 450 nm 1 .
, . , CCD
3 .
.
2013/04/10( )

2 Observation 15
2.3
,
. 4, 7, 8 .
(UT)
1 4/9∼4/15 10,12, 13,14,15 4 29 (75 pixel) 80 ◦
2 4/23∼4/26 24, 25,26 2 33 (85 pixel) 70 ◦
3 6/21∼6/29 24,25,26,27,28, 29 5 50 (130 pixel) 37 ◦
4 7/16∼7/23 16,17,18,19,20,21 6 33 (85 pixel) 70 ◦
5 8/14∼8/21 14,17,18,21 4 22 (57 pixel) 92 ◦
6 10/23∼10/27 23, 24, 25, 26 4 16 (41 pixel) 125 ◦
7 11/28∼12/6 - 0 14 (35 pixel) 140 ◦
Table 2.3:
Figure 2.3: MSI 2012/4/14, 2012/7/16, 2012/8/18 (JST)
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3 Data Reduction & Analysis 16
3 Data Reduction & Analysis
3.1
•
. MSI
. MSI
CCD
. CCD
. 10
. . CCD 1
.
. CCD
. MSI
5 , 1 . 2
( - ) / ( - ) =
.
Figure 3.1: 2012/7/17 : :
, 2
50 × 50 .
2013/04/10( )

3 Data Reduction & Analysis 17
•
,
() , MSI
. NASA Web HORAIZONS
Web-Interface → http://ssd.jpl.nasa.gov/horizons.cgi ,
.
-, , ()
, .
,
.
.
,
r = 6051.8 + 70 km
MSI s = 0.389 arcsec/pixel
, ψ Sun , θ Sun , ψ Obs , θ Obs ,
⃗ L S =
⃗ L O =
⎛
⎜
⎝
⎛
⎜
⎝
r cos θ S cos(ψ S − ψ O )
r cos θ S sin(ψ S − ψ O )
r sin θ S
r cos θ O cos(ψ O − ψ O )
r cos θ O sin(ψ O − ψ O )
r sin θ O
⎞
⎟
⎠ (1)
⎞
⎟
⎠ (2)
.
Figure 3.2 , LO ⃗ X
, Z (X, Y, Z) .
, LO ⃗ CCD y, z (x,
y, z) . xyz , CCD , XYZ Y
θ Obs .
2013/04/10( )

3 Data Reduction & Analysis 18
, CCD .
(Xpix, Ypix) xyz .
CCD
Figure 3.2:
y ′ = k Xpix (3)
z ′ = k Y pix (4)
x ′ = √ R 2 − y 2 − z 2 (5)
x x > 0
k
k =
R s
60 · 60 · 180 · π
(6)
R HORAIZONS -.
CCD P’ (x’, y’, z’) .
2013/04/10( )

3 Data Reduction & Analysis 19
P’ (x’, y’, z’) P (x, y, z)
⎛ ⎞ ⎛
⎞
x cos θ O x ′ − sin θ O z ′
⎜ ⎟ ⎜
⃗L P = ⎝ y ⎠ = ⎝ y ′ ⎟
⎠ (7)
z sin θ O x ′ + cos θ O z ′
. (1), (2), (7) Figure 3.4
.
⃗L P · ⃗ LO
| ⃗ L P | · | ⃗ L O | > 0 (8)
⃗L P · ⃗L S
| ⃗ L P | · | ⃗ L S | > 0 (9)
, MSI 512 × 128 pixel
, (Xpix, Ypix) (8), (9) 1,
0 .
Figure 3.3: MSI
2013/04/10( )

3 Data Reduction & Analysis 20
• MSI
MSI
, (Ypix )
. HORAIZONS
, MSI . MSI
.
MSI
. Xpix -256
∼ 256, Ypix -64 ∼ 64 ,
.
Xpix, Ypix
. (Xpix, Ypix)
.
Figure 3.4: Xpix Xpix
2013/04/10( )

3 Data Reduction & Analysis 21
Figure 3.5: Ypix Ypix
HORAIZONS
MSI Figure 3.6 ,
Ypix .
Figure 3.6:
2013/04/10( )

3 Data Reduction & Analysis 22
•
,
. ( ∼70 km)
P (x, y, z) ,
.
θ = θ Obs + sin −1 (z/r) (10)
ψ = ψ Obs + sin −1 (y/r cos θ) (11)
CCD , (3),
(4), (5), (7) x, y, z r .
2013/04/10( )

3 Data Reduction & Analysis 23
3.2 1 :
,
-5 ◦ ∼ 5 ◦ 70 ◦ 10 ◦
. 10 ◦ ,
, 2 arcsec 33 arcsec
. ,
, 10 ◦ .
.
Figure 3.7:
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3 Data Reduction & Analysis 24
3.3 2 :
7 .
. ,
. ,
3.1
.
,
(8), (9) . ,
B Sphere ,
B Obs =
⃗ L P · ⃗ LO
| ⃗ L P | · | ⃗ L O |
(12)
, .
Figure 3.8:
, () B Imitation ,
B Imitation = B Obs · B Sun =
L ⃗ P · LO ⃗
| L ⃗ P | · | L ⃗ O | ·
⃗L P · ⃗L S
| L ⃗ P | · | L ⃗ S |
(13)
, .
Figure 3.9:
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3 Data Reduction & Analysis 25
, MSI
.
Figure 3.10:
. , Appendix (60 ◦ , 70 ◦ )
.
2013/04/10( )

4 Results 26
4 Results
3.2 10 ◦ × 10 ◦
. ,
.
, .
1 ÷ . 7
Figure 4.1, 4.2 . (
) 20 ◦ 40 ◦
. ,
. Appendix .
7 5 . 1
8 1 .
3 ,
.
. Figure 4.1, 4.2
. (Figure 4.3 ∼ 4.12) , Figure 4.13, 4.14
. 20 ◦
, 20 ◦ .
2013/04/10( )

4 Results 27
○ 7 . 2012/7/17 -2012/7/22
(JST) .
Figure 4.1: 20 ◦ 7
Figure 4.2: 40 ◦ 7
2013/04/10( )

4 Results 28
○ 1 . ∼ 1 ∼
Figure 4.3: 20 ◦ 1
Figure 4.4: 40 ◦ 1
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4 Results 29
○ 1 . ∼ 2 ∼
Figure 4.5: 20 ◦ 2
Figure 4.6: 40 ◦ 2
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4 Results 30
○ 1 . ∼ 3 ∼
Figure 4.7: 20 ◦ 3
Figure 4.8: 40 ◦ 3
2013/04/10( )

4 Results 31
○ 1 . ∼ 4 ∼
Figure 4.9: 20 ◦ 4
Figure 4.10: 40 ◦ 4
2013/04/10( )

4 Results 32
○ 1 . ∼ 5 ∼
Figure 4.11: 20 ◦ 5
Figure 4.12: 40 ◦ 5
2013/04/10( )

4 Results 33
○ Figure 3.4 .
Figure 4.13: 20 ◦
Figure 4.14: 40 ◦
2013/04/10( )

5 Discussion 34
5 Discussion
5 ,
. 4
. ,
.
Figure 1.5 1979
. 20 ◦ 40 ◦
. 1 20 ◦ 40 ◦
. 2
.
4 ,
20 ◦ 40 ◦ . , 5
. , 2
Figure 4.13, 4.14 ,
. 1 ,
.
, .
10 ◦ 2.7 arcsec
, 1,050 km .
20 ◦ 990 km, 40 ◦ 800 km . 4
, 1 400 km 8 3,200 km
. Table.6, 7 20 ◦ 40 ◦ Results 1
Ratio()
. Max − Min
, 1 ∼ 20% ,
3,200 km .
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5 Discussion 35
Day Max Min Max − Min
1 0.9843 0.9620 0.0223
2 0.9940 0.9285 0.0655
3 0.9536 0.7737 0.1799
4 0.9886 0.8203 0.1683
5 0.9671 0.9484 0.0187
Table 5.1: 20 ◦ 1 Ratio
Day Max Min Max − Min
1 0.5963 0.5701 0.0262
2 0.5676 0.5051 0.0625
3 0.5682 0.4298 0.1384
4 0.5487 0.4808 0.0679
5 0.5505 0.5128 0.0377
Table 5.2: 40 ◦ 1 Ratio
,
.
, ,
. Summary & Future Work
, ,
.
2013/04/10( )

6 Summary & Future Work 36
6 Summary & Future Work
Galileo, Pioneer Venus Venus Express
,
. ,
,
.
7 ∼
.
, (∼1 ) , 1
(∼8 ) ∼10%, ∼20%
. , 2
.
,
.
, .
,
.
.
Venus Express VMC
(Venus Monitoring Camera) . Venus Express
VMC
.
, VMC
, MSI
.
, MSI . 365 nm
, .
,
.
7 ,
,
.
2013/04/10( )

6 Summary & Future Work 37
Figure 6.1: 30,000 km VMC VMC UV
365 nm, 40 nm
2013/04/10( )

7 Appendix 38
7 Appendix
Results 10 ◦ − −70 ◦
.
Figure 7.1: 10 ◦
Figure 7.2: 20 ◦
2013/04/10( )

7 Appendix 39
Figure 7.3: 30 ◦
Figure 7.4: 40 ◦
2013/04/10( )

7 Appendix 40
Figure 7.5: 50 ◦
Figure 7.6: 60 ◦
2013/04/10( )

7 Appendix 41
Figure 7.7: 70 ◦
.
Figure 7.8: 10 ◦
2013/04/10( )

7 Appendix 42
Figure 7.9: 20 ◦
Figure 7.10: 30 ◦
2013/04/10( )

7 Appendix 43
Figure 7.11: 40 ◦
Figure 7.12: 50 ◦
2013/04/10( )

7 Appendix 44
Figure 7.13: 60 ◦
Figure 7.14: 70 ◦
2013/04/10( )

8 Acknowledgments 45
8 Acknowledgments
, .
,
, .
,
.
,
.
.
,
.
.
2013/04/10( )

9 References 46
9 References
• Del Genio, A. D., Rossow, W. B. (1982),Temporal variability of ultraviolet cloud
features in the Venus stratosphere., Icarus, 51, 391-415.
• Del Genio, A. D.; Rossow, W. B. (1990), Planetary -scale waves and the cyclic
nature of cloud top dynamics on Venus., J. Atmos. Sci., 47, 293-318.
• Molaverdikhani, Karan; McGouldrick, Kevin; Esposito, Larry W. (2012), The
abundance and vertical distribution of the unknown ultraviolet absorber in the
venusian atmosphere from , sis of Venus Monitoring Camera imges, Issue 217,648-
660.
• Peralta, J.; Hueso, R.; S nchez -Lavega, A. (2007), Cloud brightness distribution
and turbulence in Venus using Galileo violet images, Icarus 188, 305-314
• Peralta, J.; Hueso, R.; S nchez -Lavega, A. (2007), A re, sis of Venus winds at two
cloud levels from Galileo SSI images, Icarus 190, 469-477
• Rossow, W.B., Del Genio, A.T., Limaye, S.S., Travis, L.D., Stone, P., 1980. Cloud
morphology and motions from Pioneer Venus images. J. Geophys. Res. 85, 8107-
8128.
• Rossow, W.B.,DelGenio,A.D.,Eichler,T.,1990.Cloud-trackedwindsfrom pioneer Venus
OCPP images .Journal of the Atmospheric Sciences 47, 2053-2084.
• Watanabe, M., Y. Takahashi, M. Sato, S. Watanabe, T. Fukuhara, K. Hamamoto,
A. Ozaki (2012), MSI: visible multi-spectral imager for 1.6-m telescope of Hokkaido
University, SPIE, 8446, 84462O-84462O-10.
• , 2011, ,
2013/04/10( )