reprocessed constant calibration l1c ott drift study
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SMOS L2 Ocean Salinity
Reprocessed constant calibration L1c OTT drift study
13 April 2011
ARGANS & L2OS ESL
ascending descending
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SMOS L2 Ocean Salinity
L1c reprocessed constant calibration data: pre-select South Pacific half-orbits:
> 2000 grid points in region latitude -30 to 0, longitude -130 to -120
select one half orbit at 6 day intervals:January - December 2010
sub-set ascending (58) & descending (58) orbits
OTT1 made using L2OS v500 candidate &compareTBs v1.3, latitude -50 to +10
snaps filtered for:far from land, sun/galactic glint, tec gradient > 20
+0.5 K drift = -1 psu
Reprocessed constant calibration L1c OTT
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SMOS L2 Ocean Salinity
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SMOS L2 Ocean Salinity
L2OS galactic model error: -1K in HH
Drift: -0.5 K pa in HH & VV, ascending orbits
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SMOS L2 Ocean Salinity
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SMOS L2 Ocean Salinity
L2OS galactic model error: +1K in HH & VV
Drift: +0.5 K pa in HH & VV, descending orbits
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SMOS L2 Ocean Salinity
Drift -0.5 K pa in HH & VV, same as AFFOVBut HH bias now higher then VV (opposite to AFFOV), & unexplained low VV January – end March
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SMOS L2 Ocean Salinity
Drift +0.5 K pa in HH & VV, same as AFFOVBut HH bias now higher then VV (opposite to AFFOV), & unexplained low HH & VV January – end March
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SMOS L2 Ocean Salinity
OTT anomaly 20101104T020829reversed HH & VV bias – why?
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SMOS L2 Ocean Salinity
Cross-pol OTT drifts different from HH & VV in AF & EAF
ascending descending
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SMOS L2 Ocean Salinity
ascending descendingDescending OTTs show sun alias moving along AFFOV/EAFFOV hexagon
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SMOS L2 Ocean Salinity
OTT2 from L1B OTT1 from L1COTTs from L1B (Joe) & L1C (ARGANS) visual match
orbit 20101110T013458_20101110T022859
XX/HH
YY/VV
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SMOS L2 Ocean Salinity
• Conclusions– reprocessed constant calibration data allows identification
of long-term drift• ESL recommendation for 2011 reprocessing
– long-term drift:• -0.5 K pa in HH & VV, ascending orbits• +0.5 K pa in HH & VV, descending orbits
– cross-pol noise/errors?– sun aliases in EAFOV?– L2OS work
• correct galactic model error ±1 K• why short-term OTT irregularities?• refine OTT generation procedures
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SMOS L2 Ocean Salinity
• Extra slides follow, showing– short integration time OTTs close to long– median OTTs different from mean– impact on OTT quality from too few snapshots
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SMOS L2 Ocean Salinity
AFFOV OTTs from FP short integration time close to long
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SMOS L2 Ocean Salinity
AFFOV OTTs from FP short integration time close to long
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SMOS L2 Ocean Salinity
EAFFOV OTTs from FP short integration time close to long
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SMOS L2 Ocean Salinity
EAFFOV OTTs from FP short integration time close to long
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SMOS L2 Ocean Salinity
median AFFOV OTTs different from mean
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SMOS L2 Ocean Salinity
median AFFOV OTTs different from mean
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SMOS L2 Ocean Salinity
median EAFFOV OTTs different from mean
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SMOS L2 Ocean Salinity
median EAFFOV OTTs different from mean
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SMOS L2 Ocean Salinity
tec gradient filter > 5 tec gradient filter > 20TEC filter reduces number of snapshots: 21 snapshots (left), 210 (right)
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