smos l1v620-l2v613 versus l1v505-l2v550 validation may 2011
DESCRIPTION
SMOS L1v620-L2v613 versus L1v505-L2v550 validation May 2011. Nicolas Martin, Jacqueline Boutin LOCEAN. 26 May 2014. All the metrics SMOS-ARGO and SMOS-ISAS, as well as a complete descriptions of flags, are available on: http://www.locean-ipsl.upmc.fr/~martin/work/L1Cv620_L2OPv613 . - PowerPoint PPT PresentationTRANSCRIPT
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SMOS L1v620-L2v613 versus L1v505-L2v550 validation
May 2011
Nicolas Martin, Jacqueline Boutin
LOCEAN26 May 2014
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All the metrics SMOS-ARGO and SMOS-ISAS, as well as a complete descriptions of flags, are available on:
http://www.locean-ipsl.upmc.fr/~martin/work/L1Cv620_L2OPv613
Observations (at >800km from coast; stats for whole ocean including <800km from land available on web site):
-Careful must be taken as L1 AND L2 versions are diffferent
-SMOS-ARGO colocations in radii of 9days-100x100km2 are much noisier than SMOS-ISAS monthly comparisons and hence conclusions less clear => in this ppt, we show only SMOS-ISAS
-Ascending orbits (next slide) : mean bias is reduced (possibly an effect of daily OTT in new L2) but a positive bias in the northern Pacific, we do not see what in L2 change could create this; likely to be a remaining drawback of L1; larger RFI pollution in Northern Atlantic in v6 than v5: L1 RFI flags not sufficient, RFI flags in L2 need to be optimized,
-Descending orbits: improvement of north-south bias likely an effect of TEC retrieval (not an L1 effect) => not shown in this ppt as it does not concern L1
-Land effect: still there (<0 bias) + larger std in v6: possibly RFI sorting less efficient!
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S[SMOS A]-S[ISAS] - L1Cv620_L2OPv613
S[SMOS A]-S[ISAS] - L1Cv504_L2OPv550
Ascending orbits : mean bias is reduced (possibly an effect of daily OTT in new L2) but a positive bias in the northern Pacific, we do not see what in L2 change could create this; likely to be a remaining drawback of L1; larger RFI pollution in Northern Atlantic in v6 than v5: L1 RFI flags not sufficient, RFI flags in L2 need to be optimized (they have change from L2 v5 to L2v6),
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Mean difference and std of the difference per region– red: v6; blue: v5Ascending orbits
Mean bias is reduced BUT STD is not improved (even slightly worse on ARGO comparisons see www page); only large scale bias improved
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Effect of land vicinity (D<800km) : Ascending orbits; still <0; larger std, RFI?
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Effect of land vicinity (D<800km) : Descending orbits; still <0; larger std, RFI?
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Descending orbits results
Be careful that TEC was retrieved in L2 v6 but not in L2 v5 => latitudinal biases are
reduced due to TEC retrieval (see last slides of this presentation shown at QWG 13)
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Slides from QWG 13
TEC retrieval in L2 reduces latitudinal biases in descending orbits
(tests conducted using same L1c)
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L2V611b, OTT A3TEC on- A3TEC prior – no TEC dwell retr.
SMOS SSS - ISAS SSS: descendingPCTVAR<80% (exclude regions with no ARGO) and 700km far from land
L2V550OTT L1cTEC – L1cTECprior – TEC dwell retr.
L2V611b, OTT L1cTEC – A3TEC ‘prior’ -no TEC dwell retr.
L2V550OTT A3TEC on - L1cTEC prior –TEC dwell retr.
‘OTT A3TEC on- A3TEC prior – no TEC dwell retr.’ give best retrieved SSS compared with ISAS SSS.
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SMOS SSS - ISAS SSS: descendingMetrics
For descending orbits, when ISAS-PCTVAR<80% and SMOS at 700km further from land, ‘OTT A3TEC on- A3TEC prior – no TEC dwell retr.’ give lowest differences (mean and std) compared with ISAS SSS over the global ocean.
Global: mean=0.106 (std=0.389)[45S45N;180W180E] : mean=0.0535(std=0.320)[30S30N;180W180E] : mean=-0.006 (std=0.288)
Global: mean=0.188 (std=0.442)[45S45N;180W180E] : mean=0.112 (std=0.362)[30S30N;180W180E] : mean=0.019 (std=0.319)
mean=0.002(std=0.355)mean=-0.010 (std=0.286)mean=-0.016 (std=0.270)
mean=-0.034 (std=0.408)mean=-0.084 (std=0.343)mean=-0.163 (std=0.306)
L2V550OTT L1cTEC – L1cTECprior – TEC dwell retr.
L2V550OTT A3TEC on - L1cTEC prior –TEC dwell retr.
L2V611b, OTT L1cTEC – A3TEC ‘prior’ -no TEC dwell retr.
L2V611b, OTT A3TEC on- A3TEC prior – no TEC dwell retr.