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The SST Quality Monitor (SQUAM) : an overview

GHRSST Joint DVWG, HL-TAG & ST-VAL workshop 28 Feb – 02 Mar, 2011, Boulder, CO. The SST Quality Monitor (SQUAM) : an overview. www.star.nesdis.noaa.gov/sod/sst/squam. Prasanjit Dash 1,2 and Alexander Ignatov 1 1 NOAA/NESDIS, Center for Satellite Applications & Research (STAR)

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The SST Quality Monitor (SQUAM) : an overview

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  1. GHRSST Joint DVWG, HL-TAG & ST-VAL workshop28 Feb – 02 Mar, 2011, Boulder, CO The SST Quality Monitor (SQUAM) :an overview www.star.nesdis.noaa.gov/sod/sst/squam Prasanjit Dash1,2 and Alexander Ignatov1 1NOAA/NESDIS, Center for Satellite Applications & Research (STAR) 2Colorado State Univ, Cooperative Institute for Research in the Atmosphere (CIRA) Objective: A global, web-based, community, quasi NRT, monitor for SST producers & users !

  2. Contributions/Support • AVHRR Level 2 SSTs: • J. Sapper, Y. Kihai, B. Petrenko, J. Stroup:NESDIS ACSPO • P. LeBorgne:O&SI SAF MetOp-A FRAC • D. May, B. McKenzie:NAVO SEATEMP • AVHRR Level 3 SST: • K. Casey, T. Brandon, R. Evans, J. Vazquez, E. Armstrong:PathFinder v5.0 • Level 4 SSTs: • R. Grumbine, Xu Li, B. Katz:RTG (Low-Res & Hi-Res), GSI • R. Reynolds:OISSTs (AVHRR & AVHRR+AMSRE) • M. Martin:OSTIA foundation, GHRSST Median Product Ensemble • D. May, B. McKenzie:NAVO K10 • E. Autret, J.-F. Piollé:ODYSSEA • E. Maturi, A. Harris, J. Mittaz:POES-GOES blended • B. Brasnett:Canadian Met. Centre, 0.2 foundation • Y. Chao:JPL G1SST • L4s in SQUAM pipeline: • H. Beggs:ABOM GAMSSA • C. Gentemann:MISST • M. T. Chin, J. Vazquez, E. Armstrong:JPL MUR • M. Martin, J. Roberts-Jones:OSTIA reanalysis extended history (1985-2007) • GHRSST support: • Craig Donlon, Matt Martin, Andrea Kaiser-WeissAnd the ORGANIZERS: 2x-Gary, Sandra

  3. Objectives of SQUAM • Initial: • Monitor NESDIS MUT and ACSPO SSTs for stability, self-consistency, cross-consistency (platform, product) • Evaluate satellite SST products daily in global domain, against global L4 fields (complements the validation against in situ SSTs) • Quickly facilitate product diagnostics (e.g., identify anomalies due to sensor malfunction, cloud mask, or SST algorithm) • Subsequent: • Other L2 (e.g., NAVO, O&SI SAF), L3 (PFv5.0) & L4 SSTs were included • and consequently now………..

  4. Current list of SSTs included in SQUAM • In pipeline: • L2 : SEVIRI (ACSPO & NESDIS operational) • L4: ABOM GAMSSA, REMSS MISST, JPL MUR • Locate this website: • Google: “NESDIS + SQUAM”, the first hit

  5. SQUAM approach: Premises of comparing against L4 • In situ measurements have limitations: • Sparse and geographically biased (HL even worse) • Quality non-uniform and suboptimal • Not available in NRT in sufficient numbers (ISAR presentation, AATSR, SEVIRI) Jan 2011 global insitu data, ~ 45K/dy, src: http://www.star.nesdis.noaa.gov/sod/sst/iquam/ • SQUAM complements heritage VAL against in situ: • ΔTS = SST to be monitored (TS) – reference L4 SST (TR)

  6. L2/3 SQUAM • Tabs for analyzing ΔTS (sat SST – L4): • Maps • Histograms • Time series (Gaussian moments, outlier info, & double differences) • Dependencies (on geophysical and observational parameters) • Hovmöller & alike (as is applicable) The SST Quality Monitor (SQUAM)Journal of Atmospheric & Oceanic Technology, 27, 1899-1917, 2010

  7. L2/L3 SQUAM: Maps of ΔTS (TS-TR) NESDIS ACSPO MetOp-A FRAC - OSTIA Maps are used to assess satellite SST globally “at a glance” O&SI SAF MetOp-A FRAC – OSTIA More FRAC analyses at: http://www.star.nesdis.noaa.gov/sod/sst/squam/FRAC/

  8. L2/L3 SQUAM • Tabs for analyzing ΔTS (sat SST – L4): • Maps • Histograms • Time series (Gaussian moments, outlier info, & double differences) • Dependencies • Hovmöller & alike (as is applicable)

  9. L2/L3 SQUAM: Histograms of ΔTS (TS-TR) NESDIS MUT NOAA-19 - OISST Gaussian parameters and outlier info are used in time-series plots NAVO SEATEMP NOAA-19 - OISST More MUT analyses at: http://www.star.nesdis.noaa.gov/sod/sst/squam/MUT/ More NAVO analyses at: http://www.star.nesdis.noaa.gov/sod/sst/squam/NAVO/

  10. L2/L3 SQUAM • Tabs for analyzing ΔTS (sat SST – L4): • Maps • Histograms • Time series (Gaussian moments, outlier info, & double differences) • Dependencies • Hovmöller & alike (as is applicable)

  11. L2/L3 SQUAM: Timeseries of ΔTS (TS-TR) NESDIS MUT AVHRR SST vs. Reynolds nighttime, each point ~0.5mi SST val against in situ nighttime, each point ~5K

  12. L2/L3 SQUAM: Double differences of ΔTS DD can alleviate the issue of space-time mismatch by using a third transfer standard • SSTDay-Night = (SSTDay – L4) – (SSTNight – L4) • If the L4s are compensated for DV corresponding to SST (x,t), then one would expect the curves to flatten out: Global Validation of DV models • similar technique for cross-platform consistency (see SQUAM web!)

  13. L2/L3 SQUAM • Tabs for analyzing ΔTS (sat SST – L4): • Maps • Histograms • Time series (Gaussian moments, outlier info, & double differences) • Dependencies • Hovmöller & alike (as is applicable)

  14. L2/L3 SQUAM: Artifical dependency detection The SQUAM diagnostics helped uncover a bug in the MUT SST which was causing across-swath bias >0.7K. After correction, bias reduced to ~0.2K and symmetric with respect to nadir. Such ‘retrieval-space’ dependent biases are difficult to uncover using customary validation (will take a long time) (as to why customary validation is inadequate!)

  15. L2/L3 SQUAM • Tabs for analyzing ΔTS (sat SST – L4): • Maps • Histograms • Time series (Gaussian moments, outlier info, & double differences) • Dependencies • Hovmöller & alike (as is applicable)

  16. “Pathfinder v5.0 (Day) - OISST” vs. Wind Speed NOAA-17 mid-morning platform – Diurnal warming suppressed Platforms Year http://www.star.nesdis.noaa.gov/sod/sst/squam/PF/ Wind Speed (ms-1)

  17. L4-SQUAM • Inter-compare L4 SSTs via similar diagnostics (maps, histograms …) • Validate consistently against quality controlled in situ data • IC-TAG

  18. http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/

  19. “OISST – CMC” mean zonal difference Year HL issues, calls for consensus between the L4 developers More combinations at: http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/ Latitude

  20. “L4s– drifters”: time series statistics More time-series at: www.star.nesdis.noaa.gov/sod/sst/squam/L4/l4_delsst_timeseries.htm Mean Std Dev wrt drifters wrt drifters Year Year Roughly, L4 products form 3 major groups (when compared against GMPE): DOI_AV,DOI_AA,RTG_LR,NAVO K10, G1SST RTG_HR,GOES-POES blended (with seasonal variation between: RTG_HR, RTG_LR) OSTIA,CMC,&GMPE

  21. “L4 val against drifters: summary stats”

  22. L4-SQUAM highlights • Planned community publications in Deep-Sea Res-II, Special Issue (proposed abstracts accepted; manuscripts are due in June 2011): • 1. Group for High Resolution SST (GHRSST) Analysis Fields Inter-Comparisons: Part 1. A Multi-Product Ensemble of Sea Surface Temperature Analyses • Matthew Martin1, Prasanjit Dash2,3, Alexander Ignatov2, Craig Donlon4, Alexey Kaplan5, Robert Grumbine6, Bruce Brasnett7, Bruce McKenzie8, Jean-Francois Cayula9, Yi Chao10, Helen Beggs11, Eileen Maturi2, Chelle Gentemann12, James Cummings13, Viva Banzon14, Shiro Ishizaki15, Emmanuelle Autret16, David Poulter17 • Group for High Resolution SST (GHRSST) Analysis Fields Inter-Comparisons: Part2. Near real time web-based Level 4 SST Quality Monitor (L4-SQUAM) • Prasanjit Dash1,2, Alexander Ignatov1, Matthew Martin3, Craig Donlon4, Robert Grumbine5, Bruce Brasnett6, Doug May7, Bruce McKenzie7, Jean-Francois Cayula8, Yi Chao9, Helen Beggs10, Eileen Maturi1, Andy Harris1,11, John Sapper12, Toshio M. Chin9, Jorge Vazquez9, Edward M. Armstrong9 • Add remaining L4s • DV model val (for foundation SSTs) • Transfer processing from STAR (mimicking ops) to operational facility. Any volunteer ??

  23. Summary and Future Work • SQUAM currently monitors all “major Global” L2 AVHRR SST, L3 PF v5.0, and ~11 L4 SST products • They mostly show cross-platform and day-night consistency but there is room for improvement • Double Diff. may be useful for global Val of DV models • Highlights the HL discrepancies between various L4 products • Future plans • Include remaining L4 SSTs • Add in situ val in SQUAM page for L2/L3 (done for L4) • Include Geostationary capabilities (prototype) • Include non-AVHRR polar products (MODIS, AATSR ….) • Find a way to link to HR-DDS (vice versa) – spoke with Dave P. SQUAM: http://www.star.nesdis.noaa.gov/sod/sst/squam THANK YOU!

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