Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.iki.rssi.ru/oct4/2007/ppt/02_16_J-L_Bertaux.pdf Äàòà èçìåíåíèÿ: Tue Dec 4 17:08:31 2007 Äàòà èíäåêñèðîâàíèÿ: Sat Apr 12 20:59:32 2008 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï

Structure and composition of Venus atmosphere from the SPICAV/SOIR · J.L. Bertaux (1), A. Fedorova (3), O. Korablev (3), E. Villard (1), E. Neefs (2), F.Montmessin(1), A.C.Vandaele (2), V. Wilquet (2), A. Mahieux (2),D.Belyaev (3)

· (1) Servic e d'AÈronomie du CNRS/IPSL, Universit y of Versailles Saint-Quentin, BP 3, 91371, VerriÕres-le-Buisson, France. · (2) Belgian Institute for Space Aeron omy, 3 av. Circulaire, B-1180 Brussels, Belgium. · (3) Space Res earch Institute (IKI), 84/32 Profs oyuznaya, 117810 Moscow, Russia.
50th anniversary Sputnik celebration, IK I, Moscow, 1-4 October 2007


THE SPICAV-SOIR INS TRUME NT


VE X P AYLO AD

VE X Payload : 7 instru ments MAG : magneto meter VIRT IS : i maging spectro meter PFS : Fourier spectrometer VMC : monitoring ca mera VER A : radio science ASPER A : space plas ma SPIC AV/SO IR : U V/ IR spectro meter


SPICAV/ SOIR ON VEX

SOIR : 2.2 - 4.3 µm

UV : 110 - 310 nm IR : 0.7 - 1.7 µm shutter


Star Occultation:operating on Earth, Mars, Venus
SPICAM ­ Ultra-Vi olet ob serva ti on s, orb i t 17, 13 jan. 2004 Spectru m of the star :
outside the atmo sphe re through th e atmo spher e
ratio

Atmo sp heri c Tran smi ssi on

Ve nu s EXPRESS
SPICAV

Line of sigh t

Star Orbit Atmosphere

VENUS


UV stellar occultation


Stellar Occultation: CO2 and aeros ol quantities in version

Model Data

CO2

aero so ls


Temperature profile retrieval


Before SPICAV/VE X: Venus Nig ht Side mes osp here (60 Night side temperature of Venus Atmosphere
140

120

Altitude (km)
100

80

Lellouch et al.1994 Pioneer Venus Night Probe 1978 Clancy et al. 2003 VIRA85 empirical model Zasova et al (2006) T_eq_night

80

100

120

140

160

180

200

220

Temperature (K)


140

120

Altitude (km)

Lellouch et al.1994 Pioneer Venus Night Probe 1978 Clancy et al 2003 Orb. 95 (Lat/LT= 38.9°/20:44) Orb. 96 (Lat/LT= 38.9°/20:51) Orb. 98 (Lat/LT= 38.9°/21:04) Orb. 102 (Lat/LT= -4.2°/23:14) Orb. 103 (Lat/LT= -4.2°/23:20) Orb. 104 (Lat/LT= -4.2°/23:27)

100

80

Night side temperature of Venus Atmosphere
80 100 120 140 160 180 Temperature (K) 200 220 240


Venus seen from night side
North
1.0

0.5

200 K Evenin g

Mornin g

0.0

230 K
-0.5

-1.0 -1. 0 -0.5 0. 0 0. 5 1.0


Sub- solar Antisolar circulation: thermosphere z>100 km
Mesosphere 60-100 km

mornin g

NP

evening Zonal super rotation: troposphere z<60+ km?

Region of a ir subsidence: adiabatic heating, O2, NO emission s


A VIRTIS im age of O2 1.27 µm emission, a tracer of descen ding air on the night side

· Air desce nt area is large, but not on the whole nig htside pla net. · Is the SPICAV hot layer distributed in the same fas hio n ? · Whe n there is O2 emissio n, there is a descent
But there may be a descent without O2 emission (if no more O atoms)


SOIR data analysis


Star Occultation:operating on Earth, Mars, Venus
SPICAM ­ Ultra-Vi olet ob serva ti on s, orb i t 17, 13 jan. 2004 Spectru m of the star :
outside the atmo sphe re through th e atmo spher e
ratio

Atmo sp heri c Tran smi ssi on

Ve nu s EXPRESS
SPICAV

Line of sigh t

Star Orbit Atmosphere

VENUS


SPICAV/ SOIR ON VEX

SOIR : 2.2 - 4.3 µm

UV : 110 - 310 nm IR : 0.7 - 1.7 µm shutter


SOIR : SPECTR OMETER SC HEME (OIP,Belgiu m)
compactin g e xerc ise

(3) AOT F (7) echelle grat in g

(9) folded detector optics (10) detector assembly placed upright (SOFRADIR,France)

(8) fold in g mirror (6) collimat in g and camera lens merged into one off-axis parabolic m irror


HDO/H2O situation in Venus
· · · · · · · · Present: Equiva lent of 3 cm of water (liquid) in the atmosp here of Venus : Earth: 2.7 km T he low atmosphere is ric h in HDO: 150 times Earth value. Due to escape of H atoms, and less escape of D atoms (heavier) If there is NO escape of D atoms, then there could have been on Venus: 150x3 cm= 4.5 m Preferential conde nsatio n of HDO in ice (exists on Earth at tropopause, loss of a factor of 3), could prevent D atoms from reaching esca pe altitude (250 km) Exists also on Mars Does it exist also on Ven us ? SOIR objective


Star Occultation:operating on Earth, Mars, Venus
SPICAM ­ Ultra-Vi olet ob serva ti on s, orb i t 17, 13 jan. 2004 Spectru m of the star :
outside the atmo sphe re through th e atmo spher e
ratio

Atmo sp heri c Tran smi ssi on

Ve nu s EXPRESS
SPICAV

Line of sigh t

Star Orbit Atmosphere

VENUS


HDO detection by SOIR solar occult ation


H2O and HDO at 3 orbits, 75° N at terminator (solar occultation)

Bulk atmosphere


HDO/H2O situation in Venus
· Present: Eq uiva le nt of 3 cm of water (liquid) in the atmosp here of Ve nus : Earth: 2.7 km · The low atmosphere is ric h in HDO: 150 times Earth value. · Due to escape of H atoms, and less escape of D atoms (heavier) · If there is NO escape of D atoms, then t here could ha ve bee n on Ve nus: · 150x3 cm= 4.5 m · Preferential co nde ns atio n of HDO in ice (exists on Earth at tropopause, loss of a factor of 3), could preve nt D atoms from reaching escape altit ude (250 km) · Exists also on Mars · Does it exist also o n Ve nus ? SOIR finding: NO !

· Escape of D is possible: certainly more than 4.5 m · We wait for detection of D+ escape by ASPERA on VEX.


1.0

95 90 85

0.8

Transmittance

0.6

My ste rious spe ctral signature : not ex isting in HITRAN data base

80

Altitude (km )

0.4 75

0.2

70 0.0

2975

2980

2985

2990

2995

Wavenum ber (cm-1)


0.78

0.76

S im ul ation by A si mut fo r HCl

0.74

Transmittance

0.72

0.78

0.76

0.74

My ste rious spe ctral signature: 2982 cm -1 ty pical of C-H bond (organic)

S OIR sp e ctrum S OIR sp e ctrum Order 13 3 Order 13 3 1 1 S ep tem be r 20 06 1 1 S ep tem be r 20 06

0.72 2980 2982 2984 2986 2988 2990 2992 2994 2996

Wavenum ber (cm-1)


0.78

0.76

S im ul ation by A si mut fo r HCl

0.74

Transmittance

My ste rious spe ctral signature: The same signature see n by Mumm a e t al. on Mars !

0.72

0.78

0.76

0.74

S OIR sp e ctrum S OIR sp e ctrum Order 13 3 Order 13 3 1 1 S ep tem be r 20 06 1 1 S ep tem be r 20 06

0.72 2980 2982 2984 2986 2988 2990 2992 2994 2996

Wavenum ber (cm-1)


0.78

0.76

S im ul ation by A si mut fo r HCl

0.74

Transmittance

0.72

0.78

0.76

0.74

M ysterious signature finally identified: C12 O16 O18
2980 2982 2984 2986 2988 2990 2992

S OIR sp e ctrum S OIR sp e ctrum Order 13 3 Order 13 3 1 1 S ep tem be r 20 06 1 1 S ep tem be r 20 06

0.72 2994 2996

Wavenum ber (cm-1)


V- Identification of absorption structures
Diffraction order 132

Diffraction order 133

T heoretical spectroscopy: T ashkun and Peravalov (T omsk)


Consequences of new 628 CO2 band at 3.3 µm
· Increas ed greenhous e ef f ect on Venus · Possible c onf usion with organic biom arker gases , at Mars (and extra-solar plan ets ! ) · (Villenueva, Mumma et al.,Icarus, DPS 2007) · Emphasis on the need of high spectral resolution to study biomark ers


Conclusions
· Just the beginning of Venus Express: SOIR detected CO2 and isotope 628,H2O and HDO HCl, HF, CO, and SO2. · Venus is the only Earth like plan et within a few parsecs from the sun! · SOIR uses the atmosphere of Venus as a gigantic laboratory of spectrosc op y and fundamental physics.


V- Identification of absorption structures
Diffraction order 132

Diffraction order 133

T heoretical spectroscopy: T ashkun and Peravalov (T omsk)


V- Identification of absorption structures
CDSD database for the 4 most abundant CO2 isotopologues
Dif. order CO2 is o. 148,149

626

111,112 132, 133

628

627

Transmittance

636

2950-29 97 cm -1 wi ndow Di ffraction orders: 1 3 2 13 3

Wavenum ber (cm-1)

2918 - 3 015 cm

-1


S im ul ation by A si mut fo r HCl

Transmittance

S OIR sp e ctrum Order 13 3 11 S eptem be r 2006

S im ul ation by A si mut fo r CO2 62 8

2980

2982

2984

2986

2988

2990

2992

2994

2 996

Wavenum ber (cm-1)


Haze top variations

·

Upper ha ze top le ve l (defined b y =1) s hows variations of a ltit ude o f a lmost 10 k m duri ng t he firs t 300 orbits


Haze top variations


Haze top variations

Mysterious 9-day oscillation? See Forbes et al., yesterday


140 Lellouch et al.1994 Pioneer Venus Night Probe 1978 Clancy et al 2003 Orb. 102 (Lat/LT= -4.2°/23:14) Orb. 103 (Lat/LT= -4.2°/23:20) Orb. 104 (Lat/LT= -4.2°/23:27) 120

Altitude (km)
100 80

Night side temperature of Venus Atmosphere
80 100 120 140 160 180 200 220 240

Temperature (K)






Earth Observations


Scientific Objectives
· IR AOTF spectrometer (0.63-1.7 µm):
­ Composition of t he nightside lower at mosphe re b y detection o f t herma l emission ­ Vertical st r uct ure of H2 O, CO2 and aerosols in solar occultat ion ­ Obser vation of t he NO , O a nd O2 emissions i n the upper atmosphe re o n t he night side ­ Measurement of the vert ical d istr ibution of CO2 and aerosols, in s tel lar occulta tion ­ Determination of temperature and density vertical profi les ­ Stud y o f t he escape processes o f H a nd O a toms by obser vi ng t he L yma n- a nd O emissions ­ Measurement of the vert ical d istr ibution of many species above the cloud deck (HDO, H 2O ,HCl,HF and isotopes o f CO2 , i n par ticular) ­ Sensitive searc h fo r new species

·

UV spectrometer (118-320 nm)

·

SOIR spectrometer (2.3-4.3 µm)