The Odin satellite Swedish led mini-satellite. Cooperation with Canada, Finland, France. Launched in February Design lifetime: 2 years. Circular quasi-polar sun-synchronous orbit: ~600km altitude, 96min/orbit, 6h/18h equator crossing. Time sharing: 50% astronomy, 50% aeronomy 100% aeronomy since April 2007! Limb-sounding in aeronomy mode: ~45-65 scans/orbit, ~15 orbits per day. 2 instruments: SMR (Sub-Millimetre Radiometer), OSIRIS (Optical Spectrograph and InfraRed Imaging System) Science objectives: stratospheric and mesospheric processes

Odin long-lived tracer observations Nitrous oxide (N2O): 2-3 days / week Stratosphere ~15-50km, Sources: tropospheric (transport through TTL), Sinks: photo-dissociation (  nm, ~90%), N 2 O+O( 1 D) (~10%) Lifetime: troposphere ~100 years, 30km ~1 years, 45km ~1 month Carbon monoxide (CO): 2-3 days / month Lower stratosphere to lower thermosphere ~18-100km, Sources: CO 2 photodissociation (mesosphere + thermosphere), minor chemical source: CH 4 oxidation (stratosphere). Chemical sinks: CO + OH → CO 2 + H Lifetime: comparable or longer than typical transport timescales, e.g. ~1 week around 50 km, longer above Water vapour (H2O, H2O-18, H2O-17, HDO): 4-5 days / month Upper troposphere to lower thermosphere: H2O ~11-100km; isotopologues: ~20-70km, Sources: troposphere (transport through TTL, “cold trap”), methane oxidation, slow conversion from/to H2 in mesosphere. Sinks: photo-dissociation, reactions with O(1D), OH Lifetime: relatively long-lived in stratosphere

Carbon monoxide in stratosphere and mesosphere

Strato-mesospheric carbon monoxide Sources: CO 2 photolysis (mesosphere + thermosphere), Sources: CO 2 photolysis (mesosphere + thermosphere), minor chemical source: CH 4 oxidation (stratosphere). Chemical sinks: Chemical sinks: CO + OH → CO 2 + H Lifetime: comparable or longer than typical transport timescales, e.g. ~ 1 week around 50 km Lifetime: comparable or longer than typical transport timescales, e.g. ~ 1 week around 50 km   transport processes dominate the CO distribution in most of the middle atmosphere  tracer for global meridional circulation, coupling of troposphere-stratosphere- mesosphere, … Global observations: Global observations: 4.6 μm IR emission: UARS/ISAMS (~6 month in ), Envisat/MIPAS (6/2002-3/04), … mm/sub-mm emission: Odin/SMR (several days since Aug 2001), AURA/MLS (7/2004-).

CO data analysis Global measurements: CO GHz Global measurements: CO GHz Strat-meso scan (7-110 km) → 7 Aug 2001, 18 Nov 2001, 18 Nov 2002, Strat-meso scan (7-110 km) → 7 Aug 2001, 18 Nov 2001, 18 Nov 2002, ~1-3 days/month since Oct 2003; ~1-3 days/month since Oct 2003; Summer-meso scan ( km) → 2-14 July 2002,... Summer-meso scan ( km) → 2-14 July 2002,... LO-failure of 572 GHz radiometer  correction for frequency shift! LO-failure of 572 GHz radiometer  correction for frequency shift! Profile retrieval: altitude range ~ km, resolution ~3 km, Profile retrieval: altitude range ~ km, resolution ~3 km, single-profile precision %. 7 Aug 2001 – 3N/120W [Dupuy et al., GRL 2004]

Global CO data: seasonal variation CO 7-8 Aug 2001 CO Nov 2001 N 2 O Nov 2001 N 2 O 5 Aug 2001

Seasonal variation: CO and N2O 2003, 2004: Chalmers-v2.1 data

CCM validation Odin/SMR CO: profile comparison with ACE/FTS and CMAM ACE-FTS: infrared (2-13 μm) solar occultation (Bernath 2005) ACE-FTS: infrared (2-13 μm) solar occultation (Bernath 2005) CMAM: general circulation model (Beagley et al ) CMAM: general circulation model (Beagley et al ) CMAM ACE (4,0°S/42,3°E) SMR (0,6°N/36,2°E) Erreurs : 1σ Tropics 07/04/2004 CO mixing ratio CMAM ACE (79,5°N/9,9°E) SMR (77,4°N/3,0°E) Erreurs : 1σ High latitudes 05/03/2004 CO mixing ratio [J. Jin, E. Dupuy et al., GRL, 2005]

Atmospheric circulation: Odin vs CMAM CMAM: Canadian Middle Atmospheric Model (CCM) [data from J.Jin, K. Semeniuk et al., York University, Toronto] Jul CO - SMR CO - CMAM ~10hPa N 2 O - SMR N 2 O - CMAM Oct low bias ~100hPa CMAM: small differences in polar descent, negative N2O bias in upper stratosphere