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The 15 th GHRSST 2014 meeting, ST-VAL Breakout session 2–6 Jun, 2014, Cape Town, South Africa

The 15 th GHRSST 2014 meeting, ST-VAL Breakout session 2–6 Jun, 2014, Cape Town, South Africa. Which VIIRS product to use? NOAA ACSPO vs. NAVO SEATEMP www.star.nesdis.noaa.gov/sod/sst/squam/HR/. AUS TAG and VIIRS breakout GHRSST XV, 2014 X Jun 2014, X:XX-X:XX AM.

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The 15 th GHRSST 2014 meeting, ST-VAL Breakout session 2–6 Jun, 2014, Cape Town, South Africa

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  1. The 15th GHRSST 2014 meeting, ST-VAL Breakout session2–6 Jun, 2014, Cape Town, South Africa Which VIIRS product to use? NOAA ACSPO vs. NAVO SEATEMPwww.star.nesdis.noaa.gov/sod/sst/squam/HR/ AUS TAG and VIIRS breakout GHRSST XV, 2014 X Jun 2014, X:XX-X:XX AM Prasanjit Dash1,2, Alex Ignatov1, Yuri Kihai1,3, John Stroup1,4, John Sapper1, Boris Petrenko1,3 1NOAA NESDIS, NCWCP College Park, MD 2 Colorado State Univ, CIRA 3 GST, Inc, MD, USA 4 STG, Inc, VA, USA (Emails: FirstName.LastName@noaa.gov) SQUAM objective: A global, web-based, community, quasi NRT, monitor for SST producers & users !

  2. Acknowledgments • Level-2 SST: VIIRS/AVHRR/MODIS • NESDIS SST Team :ACSPO (GAC: 5 platforms, FRAC: Metop-A & B, VIIRS: NPP, MODIS: Terra/Aqua) • D. May, B. McKenzie : NAVO SEATEMP • S. Jackson :IDPS (NPP) • Level 4 SSTs: • M. Martin, J. R. Jones :OSTIA foundation, GHRSST Median Product Ensemble, OSTIA Reanalysis • B. Brasnett :Canadian Met. Centre, 0.2 foundation • GHRSST support:Peter Minnett, Craig Donlon, Alexey Kaplan CMC

  3. Outline

  4. 1. VIIRS SSTs in High-Res (HR) SQUAM Locate this website: Google: “SST + SQUAM + HR” The SST Quality Monitor (SQUAM), JTech, 27, 1899-1917, 2010

  5. 2. VIIRS SST in SQUAM: IDPS Night:VIIRS (IDPS) minus CMC L4, 15-May-2014 • Initial product developed by private contractor, now discontinued and replaced by ACSPO • Coverage is good but many cold spots indicate residual cloud/aerosol leakages

  6. 2. VIIRS SST in SQUAM: ACSPO Night:VIIRS (ACSPO)minus CMC L4, 15-May-2014 • ACSPO is NOAA heritage SST product, now operational and replaced the IDPS • Residual Cloud/Aerosol leakages reduced compared to IDPS

  7. 2. VIIRS SST in SQUAM: NAVO Night:VIIRS (NAVO)minus CMC L4, 15-May-2014 • Reduced coverage (VZA<54°; 2×2 pixel processing; more conservative mask) • Fewer leakages especially in the Tropics (on this particular day)

  8. 2. VIIRS SSTs in SQUAM: Example 15 May 2014, Night IDPS VIIRS – CMC ACSPO VIIRS – CMC NAVO VIIRS – CMC • IDPS vs. ACSPO • Retrieval domain: Comparable • SST performance statistics: ACSPO superior • NAVO vs. ACSPO • Retrieval domain: NAVO factor of ×2.6 smaller • SST performance statistics: Comparable

  9. 2. Monitoring in SQUAM: VIIRS SSTs, Day • Mean and Std Dev of residuals (Sat SST – OSTIA) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO Day: very similar (this figure); Night: NAVO slightly but consistently better (see SQUAM-HR webpage)(for other products: see SQUAM-HR webpage) • Monthly in situ val --- NEXT SLIDE

  10. 2. Validation: VIIRS SSTs (monthly, vs. drifters, Day) • Mean and Std Dev of residuals (Sat SST – Drifters) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO Std Dev: NAVO slightly but consistently better

  11. 3. NAVO/ACSPO Summary Statistics Monitoring wrt. CMC, 15 May 2014 Validation wrt. drifters, Feb 2014 • * QC’ed drifters from iQuam: www.star.nesdis.noaa.gov/sod/sst/iquam/

  12. 4. Looking for persistent features: Monthly aggregation Day: VIIRS (ACSPO) minusCMC L4, Apr-2014 • Negative residuals in monthly maps suggest persistent cloud/aerosol leakages • Positive residuals: Daytime diurnal warming? or NLSST algorithm artifacts?

  13. 4. Looking for persistent features: Monthly aggregation Day:VIIRS (NAVO)minusCMC L4, Apr-2014 • Some areas of the ocean are not covered even at monthly time interval • Warm spots more pronounced: Differences in NAVO./ACSPO cloud screening? or SST algorithm?

  14. 5. VAL Statistics as a Function of Scan Angle ACSPO makes retrievals in full swath whereas NAVO at VZA<54° only Within the limited VZA domain, ACSPO and NAVO Std Dev values are close ACSPO STD Dev degrade towards swath edges Degradation is more complex than merely a function of VZA, and shows some seasonality

  15. 6. Summary • There are 2 global VIIRS products: NOAA ACSPO and NAVO SEATEMP. Both are archived at PO.DAAC / NODC in GDS2 format • IDPS product is being discontinued, due to suboptimal performance & lack of users. It is currently archived at CLASS in hdf5 and will be wiped off once complete record of ACSPO VIIRS from Jan 2012-on is archived • Relative merits of ACSPO and NAVO VIIRS SSTs • NAVO global coverage is about 1/3 of ACSPO. As a result, some areas of the ocean remain uncovered by the NAVO product for extended periods up to a month • Measured in their corresponding full retrieval domains, NAVO outperforms ACSPO, by a narrow (day) to moderate (night) margin. • However, in the “intersection” domain, both products show comparable performances THANK YOU!

  16. Backup slides

  17. 2. Monitoring in SQUAM: VIIRS SSTs, Night • Mean and Std Dev of residuals (Sat SST – OSTIA) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO slightly but consistently better • (for other products: see SQUAM-HR webpage) • Monthly in situ val --- NEXT SLIDE

  18. 2. Validation: VIIRS SSTs (monthly, vs. drifters, Night) • Mean and Std Dev of residuals (Sat SST – OSTIA) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO slightly but consistently better

  19. 2. Monitoring in SQUAM: VIIRS SSTs, Day • Mean and Std Dev of residuals (Sat SST – OSTIA) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO Day: very similar (this figure); Night: NAVO slightly but consistently better • (for other products: see SQUAM-HR webpage) • Monthly in situ val --- NEXT SLIDE

  20. 2. Validation: VIIRS SSTs (monthly, vs. drifters, Day) • Mean and Std Dev of residuals (Sat SST – Drifters) closely track each other • Similar observations for other references • NAVO: # of NAVO observations ~1/3 of ACSPO Std Dev: NAVO slightly but consistently better

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