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Level 2 Ocean Salinity L2OS planning. 2 July 2014. ARGANS & SMOS L2OS ESL. L2OS evolution for metrics: AUX_DTBXY.
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Level 2 Ocean Salinity L2OS planning 2 July 2014 ARGANS & SMOS L2OS ESL
L2OS evolution for metrics: AUX_DTBXY • To support L1 & L2OS metrics, AUX_DTBXY needs extending to include snapshot statistics for L1c TBs, forward model TBs, and OTT correction TBs: for all polarisations, all 12 FOV sub-zones, & all 3 forward models. • To support A3TEC metrics, AUX_DTBXY needs extending to include retrieved TEC and associated data. • No changes to algorithm, configuration, or science products = low risk. • AUX_DTBXY to increase in size from max ~10Mb to ~13Mb • We recommend L2OS v620 is delivered September 2014 and used for reprocessing, to generate AUX_DTBXY as a reference data set for L1 & L2OS metrics, and A3TEC analysis. • Summer 2014 delivery (late – due April) will be L1 Metrics Plan (including ADD) based on draft TRUM (Tools Release User Manual) & PPSR. • L2OS v620 delivered September 2014 with Tools for L1 Metrics
L2OS evolution for metrics: AUX_DTBXY V612 v620 n x geographical regions: region ID, snap start/stop time/ID 3 x forward models 8 x polarisations ott stats deltaTB[xi,eta] std(deltaTB)[xi,eta] count(deltaTB)[xi,eta] flags[xi,eta] for each snapshot in region: ID, lat/long polarisation flags for 12 FOV sub-zones for 3 polarisations L1cTB for 3 forward models forward model TB OTT TB deltaTB measurement count A3TEC stats fov/geo lat/long, lat TEC TEC from L1c & A3, sigma n x geographical regions: region ID, snap start/stop time/ID 3 x forward models 8 x polarisations ott stats deltaTB[xi,eta] std(deltaTB)[xi,eta] count(deltaTB)[xi,eta] flags[xi,eta] for each snapshot in region: ID, lat/long polarisation flags deltaTB (0.3 circle) Max snapshots in global region ~1500, in OTT region ~500 Metrics adds < ~3Mb A3TEC adds < ~90Kb
L2OS tuning for reprocessing • Reference L2OS data sets: • v620 ref (from ESAC rehearsal) – un-tuned configuration: • L1c v620 & L2OS v612 (20110423-20110607 & 20121104 – 20130205) • v620 run2 (ARGANS) – first tuned configuration: • L1c v620 & L2OS v613 (20110423-20110607 & 20121104 – 20130205) • L1c v620 configuration update changes border width, RFI thresholds • ESL work shows need to revisit L2OS thresholds & filtering, and not to use sun tails flag to filter measurements • Reprocessing L2 starts September/October 2014?, end Jan/Feb 2015, followed by L1 & L2 catch-up reprocessing of 2014 data => end April/May 2015? • Process L1c (ESAC) May 2011 (ARGANS) in August with revised thresholds • New thresholds delivered September 2014 for L2 reprocessing
L2OS forward model sensitivity analysis – flat sea model Flat sea SST sensitivity: SST298 minus SST278 Sensitivity to SST is low in XX, but up to 0.1K/degree in YY at high incidence angles Flat sea SSS sensitivity: SSS37 minus SSS33 ~0.6K/psu at low incidence angles ~0.9K/psu at high incidence angles
L2OS forward model sensitivity analysis – wind speed • M1 XX • M2 XX • M3 XX • M1 YY • M2 YY • M3 YY General bias between roughness models of ~±0.5K at 7m/s Model updates 2010-2011: more SMOS data now => better models
L2OS forward model sensitivity analysis • Worse case (eg high incidence angle) model sensitivities • Worse case (eg high incidence angle) model absolute error estimates
L2OS evolution • Major improvements in L2OS performance from v550 to v612 from: • correction of L1 long term drift (daily OTT) • new galactic scattering model • TEC retrieval in descending orbits => better Faraday rotation • multi-threading • Work-plan for 2014-2017 identifies tasks for further improvements: • minimize flaws in L1 over ocean (biases & flagging) • refine forward models • improve filtering retrieval methods • improve quality assessment & user experience • ESL already working on these tasks with promising results (land-sea, filtering) – we expect major improvements in quality of ocean products during next phase.
L2OS follow-on ESL contract: processor delivery schedule • L2OS v630 spring 2015: • land-sea correction (WP1.1) • improved QC (WP3.1), filtering (WP1.3) • update of roughness/foam model 1 (WP 2.2) • could be use to re-reprocess L1 v620? • L2OS v640 spring 2016: • use of new constraints on roughness models (WP2.2) • better flat sea model (WP2.1) • improved GO galactic glint model (WP2.3) • new TEC product (WP3.3) • netCDF (WP4.3) • L2OS v630 spring 2017: • improved (adaptive?) retrieval algorithm(s) (WP3.2) • using new/alternative geophysical inputs (WP2.4) • mitigation of rain impact (WP2.5) • better OTT strategy (WP1.2) • comprehensive validation (WP4.1)