In situ Quality Monitor ( iQuam ) version 2 Near-real time online Quality Control, Monitoring, and Data Serving tool fo

1. SST from Polar Orbiters: Use of NWP Outputs 5-7 March 2013, OSI SAF Workshop, Lannion, France In situ Quality Monitor (iQuam) version 2 Near-real time online Quality Control, Monitoring, and Data Serving tool for SST Cal/Val http://www.star.nesdis.noaa.gov/sod/sst/iquam/ Sasha Ignatov and Feng Xu NOAA/NESDIS iQuam v2

2. Use of in situ SSTs at NESDIS Use of in situ SST • CAL(L2): Derive regression coefficients/Adjust bias in RTM • VAL (L2/L3/L4): Monitor Accuracy/Precision of satellite SST L2/L3/L4 SST products • LEO (AVHRR, MODIS, VIIRS, ABI) & GEO (GOES, MSG, MTSAT, Electro) data are matched with in situ data • SQUAM analyzes VAL statistics for L2 (ACSPO, IDPS, NAVO, OSI SAF; Geo); L3 (Pathfinder); and 10+ Level 4 products Near-Real Time NCEP GTS Data • Global Telecommunication System data available in NRT • Data quality is non-uniform & suboptimal, QC not available • Ad hoc/Simplistic/Non-uniform QC often used in satellite Cal/Val iQuam v2

3. Objectives of in situ SST Quality Monitor • Establish near-real time online in situ Quality Monitor (iQuam) which performs the following 3 functions • Quality Control:Perform accurate/flexible QC, maximally consistent with wider Meteorological and Oceanographic communities • Monitor statistical summaries of in situ minus reference SST (stratified by ships, drifters, tropical & coastal moored; ARGO; and also for individual platforms) • Serve Qced Dataonline for wider SST community • Currently, only Drifters and Tropical Moorings are employed in NESDIS operational Cal/Val • Ships and coastal moorings are also included in iQuam, and ARGO floats are being added, to explore their potential use iQuam v2

4. Quality Control – Consistent with UK MO (*) Lorenc and Hammon, 1988; Ingleby and Haddleston, 2007 iQuam v2

5. Version 2 Upgrade: Incorporate CMS and UK MO Blacklists • CMS Blacklist of drifters are updated every 10 days • iQuam QC: add flag indicating status on the CMS blacklist • UK MO Black list available from Jonah Jones-Smith or Wemma Fiedler(?) • Create iQuam’s “blacklist”: Performance History (PH) • Add in stiu platform to ‘blacklist’ if the fraction of ‘bad’ data exceeds certain threshold (e.g. 30%) in the preceding time window (e.g. 30days) – Currently under development iQuam v2

6. CMS Blacklist vs. iQuam QC • Comparative Analysis: to show the effectiveness of iQuam QC and CMS buoy blacklist and their difference. • Drifter data are separated into three subsets: • IQ x BL: passed both iQuam QC and CMS buoy blacklist check • IQ – BL: passed iQuam QC but failed CMS blacklist check (“iQuam leakage” or “CMS false alarm”) • BL – IQ: failed iQuam QC but passed CMS blacklist check (“CMS leakage” or iQuam “false alarm”) • One year data of 2011 used for this analysis • Statistics of (in situ SST vs. Reynolds) are calculated iQuam v2

7. CMS Blacklist Analysis • No. of Obs. Fraction of buoys captured by CMS BL but not captured by iQuam is ~0.6%. Fraction of buoys captured by iQuam QC but not captured by the CMS black list is 4.9% of population. iQuam v2

8. CMS Blacklist Analysis Most BL-IQ are ‘bad’ data, indicating blacklist has leakage Bias IQ-BL are more like ‘noisy’ data, however, the population is negligible. SD iQuam v2

9. Preliminary Observations from CMS Blacklist Analysis • CMS buoy blacklist appears to provide 0.6% addition to the iQuam QC • iQuam WC appears to screen out ~5% extra pixels, compared with CMS black list • More analyses are needed to understand the increase noise in data complements • iQuam QC was designed to be more conservative, to remove all potentially bad data – may screen out some diurnal warming events during the daytime • Collaboration with CMS underway to understand and resolve the differences iQuam v2

10. Version 2 Upgrade: Add ARGO • 3,654 profiles today; Good global coverage • 10-day cycle (~3 SST/month) • How to extract SST from Argo Profiles? iQuam v2

11. Add ARGO: Depth considerations • [Martin et al., 2012]: the shallowest valid data point between 3-5m depth • iQuam: The shallowest valid data point between 3-8m iQuam v2

12. Add ARGO: QC considerations • Use inherited ARGO QC • time/lat/lon pass ARGO QC • temperature/pressure pass ARGO QC • Additional ARGO QC • Vertical spike check: temperature vs. pressure gradient • Valid range: 3dbar < pressure < 8dbar • Extracted ARGO SST go through the same iQuam QC as other in situ platforms iQuam v2

13. ARGO has the most uniform coverage iQuam v2

14. Monthly Statistical Summaries Outliers detected by each QC check Moments of ΔTS=Tin situ - TReynolds Histograms of ΔTS iQuam v2

15. Time Series of Monthly Statistics (1991-pr) ARGO No of Observations No of Platforms moorings drifters ships ARGO has more platforms but smallest number of observations SD of ΔTS Bias in ΔTS ARGO compare w/Reynolds less favorably than drifter or tropical moorings – Reynolds assimilated drifters but not ARGO floats? iQuam v2

16. Monitoring individual platforms List of platforms & individual statistics Time Series of ΔTS Monthly Trajectory Error Rate History iQuam v2

17. Data for Download QC’ed data in HDF format available for download (1991-pr) Last monthly file updated in NRT every 6hrs. Initial QC performed on the fly. Final QC requires ~7 days. iQuam v2

18. Use of iQuam data in SST Quality Monitor http://www.star.nesdis.noaa.gov/sod/sst/squam/ VAL against iQuam now available in SQUAM iQuam v2

19. Summary • Online in situ Quality Monitor (iQuam) http://www.star.nesdis.noaa.gov/sod/sst/iquam/ • QC’esin situ data. QC consistent with UK MO (Lorenc and Hammon, 1988; Ingleby and Haddleston, 2007) • Reports statistical summaries stratified by data types (ships, drifters, tropical & coastal moored) and for individual platforms • Serves QC’edin situ SSTs to users via Http and aftp (Latency ~6 hrs; best QC achieved with ~7days latency) • iQuam v2 under testing, to be released soon • Include ARGO floats • Incorporate CMS blacklist iQuam v2

20. Future Work • Initial Documentation available ate • www.star.nesdis.noaa.gov/sod/osb/sst/ignatov/peer/XuIgnatov-JTech-2010_iquam_v2.pdf • Enhancements • complete adding ARGO floats • Extend time series back to 1980 (currently, 1991) • Add track obs (work with Helen Beggs) • Get rid of flash player • Explore diurnal correction in reference check • Explore adding three-way error analyses (O’Carroll et al) • Use • Generate MDBs w/AVHRR, MODIS, VIIRS ACSPO’ IDPS; OSI SAF products • Explore ships & coastal moorings in satellite CAL/VAL iQuam v2

21. Backup Slides iQuam v2

22. Inherited ARGO QC The Argo data system has three levels of quality control. • The first level is the real-time system that performs a set of agreed automatic checks on all float measurements. Real-time data with assigned quality flags are available to users within the 24-48 hrs timeframe. • The second level of quality control is the delayed-mode system. • The third level of quality control is regional scientific analyses of all float data with other available data. The procedures for regional analyses are still to be determined. • QC are done on Time, Location(lat/lon), Measurements (Temp/Pres/PSAL) iQuam v2

23. Inherited ARGO QC • Argo Real-Time QC iQuam v2

24. Inherited ARGO QC • Argo Real-Time QC (cont’l) iQuam v2

25. Inherited ARGO QC • Argo Delayed-Mode QC • For Pres/Temp/Psal • Subjective assessment of profiles of temp vs. pres, psalvs pres or temp vs. psal, with references to nearby floats and historical data. (…like manual mutual-consistency check…) • The purpose is to identify: • (a) erroneous data points that cannot be detected by the real-time qc tests • (b) vertical profiles that have the wrong shape. iQuam v2