sss maps derived from l1 v500 and l1 reprocessing commissionning and l2 v500

SSS maps derived from L1 v500 and L1 reprocessing

commissionning and L2 v500

J. Boutin, N. Martin, X. Yin

July 2010 L1 v500 Sun Off & L1 Commissionning ReprocessingNovember 2010 L1 Commissionning Reprocessing

L2 v500 reprocessed at LOCEANTested L2 flagsCTRL_SEL_GP;CTRL_VALID;CTRL_ECMWF = 1 CTRL_NUM_MEAS_MIN;CTRL_MANY_OUTLIERS;CTRL_SUNGLINT;CTRL_MOONGLINT;CTRL_GAL_NOISE;CTRL_REACH_MAXITER;CTRL_MARQ;CTRL_CHI2_P;CTRL_CHI2;CTRL_SUSPECT_RFI = 0

Data Processing

SSS maps computation

• 1°x1° SSS maps computed from averages of SMOS SSS weighted by their spatial resolution R2 and variance of the error 2 (derived by the retrieval):

N

j

N

j jjjj

j

RR

SSSSSS

1 12222

1

L1 v500 sun off

L1 Commissionning Reprocessing

L2 v500 Ascending swaths SSS Center swath July

L2 v500 Descending swaths SSS Center swath July

L1 v500 sun off

L1 Commissionning Reprocessing

L1 v500 sun off

L1 v500 Sun on or Sun off - L2 v500 Ascending swaths SSS Center swath July

L1 v500 sun on

L2 v500 Descending swaths SSS Center swath July

L1 v500 sun off

L1 v500 sun on

More stripes on L1 sun on than on L1 sun off on descending orbits! (look at the southern ocean)

L1 v500 sun off – L2 v500 Asc SSS

Error on WS 2m/sWhole swath

Center swath +/-300km

RFI better sorted out at the center of the swath

L1 v500 sun off – L2 v500 Asc N

Error on WS 2m/sWhole swath

Central swath +/-300km

L1 v500 sun off – L2 v500 Desc SSS

Error on WS 2m/sWhole swath

Central swath +/-300km

RFI better sorted out at the center of the swath

L1 v500 sun off – L2 v500 Desc N

Error on WS 2m/sWhole swath

Central swath +/-300km

Comparison with ARGOL2 V317-August 2010

SMOS -CLIMATO ARGO -CLIMATO

SMOS-ARGOSSS anomalies seen by ARGO in tropical Pacific seen by SMOS butPbs close to land, icePbs at high wind speed (see next slide), anomaly in Pacific ITCZ more negative on SMOS

Boutin et al., subm, 2011

South Pacific: SSS=0.09+/-0.56N=160

ITCZ trop Pac N:SSS=-0.18+/-0.44N=236

SMOS L2v317 - ARGO SSS (3-31 August 2010; asc orbits) versus wind speed (center of orbit)

South Indian:SSS=0.11+/-0.46N=50

Subtropical Atl N:SSS=0.1+/-0.35N=59

Colocation radii: +/-5days; +/-50km

Statistics computed after averaging over +/-5days; +/-50km over 3-12m s-1

Comparison with ARGOL1 ~v500 – L2 V500 - July 2010

SMOS -CLIMATO ARGO -CLIMATO

SMOS-ARGO

SSS too high close to ice, too low close to land

South Pacific: SSS=0.16+/-0.63N=186

ITCZ trop Pac N:SSS=-0.05+/-0.40N=248

SMOS L1v500 sun off- L2v500 - ARGO SSS (July 2010; asc orbits) versus wind speed (center of orbit)

South Indian:SSS=0.06+/-0.56N=52

Subtropical Atl N:SSS=0.02+/-0.22N=69

Colocation radii: +/-5days; +/-50kmStatistics computed after averaging over +/-5days; +/-50km over 3-12m s-1

Reduced biases wrt to commissionning reprocessing but very large std in South Pacific (cold region); in southern hemisphere bias between asc and desc

South Pacific: SSS=0.27+/-0.70N=170

ITCZ trop Pac N:SSS=0.01+/-0.43N=230

SMOS L1v500 sun on L2v500 - ARGO SSS (1-27July 2010; asc orbits) versus wind speed (center of orbit)

South Indian:SSS=0.21+/-0.55N=48

Subtropical Atl N:SSS=0.19+/-0.22N=65

Colocation radii: +/-5days; +/-50kmStatistics computed after averaging over +/-5days; +/-50km over 3-12m s-1

Very large std in South Pacific; no noticeable improvement wrt v500 sun off (even worse);in southern hemisphere bias between asc and desc

South Pacific: SSS=-0.27+/-0.85N=188

ITCZ trop Pac N:SSS=-0. 06+/-0.45N=248

South Indian:SSS=-0.14+/-0.38N=52

Subtropical Atl N:SSS=0.06+/-0.32N=67

Statistics computed after averaging over +/-5days; +/-50km over 3-12m s-1

SMOS L1v500 sun off- L2v500 - ARGO SSS (July 2010; desc orbits)

versus wind speed (center of orbit)

Very large std in South Pacific; in southern hemisphere bias between asc and desc

South Pacific: SSS=-0.15+/-0.78N=156

ITCZ trop Pac N:SSS=0. 02+/-0.51N=233

South Indian:SSS=-0.03+/-0.35N=49

Subtropical Atl N:SSS=0.23+/-0.33N=67

Statistics computed after averaging over +/-5days; +/-50km over 3-12m s-1

SMOS L1v500 sun on- L2v500 - ARGO SSS (July 2010; desc orbits)

versus wind speed (center of orbit)

Very large std in South Pacific; no noticeable improvement wrt v500 sun off;in southern hemisphere bias between asc and desc

Conclusions

• L1 v500 sun off much better than L1 commissionning reprocessing

• L1 v500 sun on does not perform better than L1 v500 sun off (even worse) ! Preliminary results; need to be consolidated on November v500!

• RFI flag works better at the center of the swath (+/-300km) than at the edge of the swath

Flags and SMOS_MODE

• Oceanographers implicated in SMOS_MODE have asked for recommendations about flags to be used Do we agree on recommending to apply:

• CTRL_SEL_GP;CTRL_VALID;CTRL_ECMWF = 1 • CTRL_NUM_MEAS_MIN;CTRL_MANY_OUTLIERS;CTRL_SUNGLINT;CTRL_MOO

NGLINT;CTRL_GAL_NOISE;CTRL_REACH_MAXITER;CTRL_MARQ;CTRL_CHI2_P;CTRL_CHI2;CTRL_SUSPECT_RFI = 0

• Add recommendation beginning of ATBD? (looking in ATBD, I haven’t find description of ctrl_poor_geophys and ctrl_poor_retrieval)

L1 Commissionning reprocessing – L2 v500 Asc July

Whole swath

Center swath

L1 Commissionning reprocessing – L2 v500 Desc July

Whole swath

Center swath

L1 commissionning reprocessing-L2 v500November (center swath -Asc)

OTT Nov

OTT July

L1 commissionning reprocessing-L2 v500November (center swath - Desc)

OTT Nov

OTT July