10. Future Work

1. Monitoring of IR Clear-sky Radiances over Oceans for SST (MICROS) from NPP/VIIRS, Terra-Aqua/MODIS and NOAA-Metop/AVHRR http://www.star.nesdis.noaa.gov/sod/sst/micros/ XingMing Liang1,2 ,Alexander Ignatov1 and Korak Saha1,2 1NOAA/NESDIS/STAR, 2Colorado State University/CIRA 1. SST and MICROS 6. MICROS Overview Sea surface temperatures (SST) are derived from brightness temperatures (BT) in the IR window bands of AVHRR, MODIS, and VIIRS sensors. Multi-Channel and Non-Linear SST (MCSST/NLSST) algorithms are unresolved combinations of several BTs. To attribute anomalies in the retrieved SSTs to a particular band, a near-real time web-based Monitoring of IR Clear-sky Radiances over Oceans for SST (MICROS) was established. MICROS is used to evaluate the stability of the VIIRS BTs, and their consistency with AVHRR and MODIS BTs. Both day and night data are processed and monitored in MICROS. However, only night data are used here, to minimize effects of diurnal cycle & solar reflectance. 2. Objectives of MICROS Monitor clear-sky sensor BTs in SST bands over global ocean in Near-Real Time (“Obs”), against CRTM with first-guess input fields (“Model”) • Evaluate sensor radiances for stability and cross-platform consistency • Contribute to Global Space-based Inter-Calibration System (GSICS) • Understand & minimize M-O biases in BTs & SSTs • Minimize the need for empirical bias correction & facilitate physical SST • Validate CRTM and first-guess input SST and upper air fields • Assist in resolving SST anomalies 3. Platforms/Sensors/Bands Monitored in MICROS • Global M-O distributions are uniform • Histograms are close to Gaussian • View zenith angle and other dependencies are near-flat • Warm M-O biases due to inaccuracies in “M” (Missing aerosols; Using bulk Reynolds instead of skin SST; Using daily mean to represent night SST in CRTM) and “O” (Residual cloud) • Temporal M-O variability is mainly due to unstable Reynolds SST input to CRTM 7. AVHRR – MODIS – VIIRS Consistency • Use Double Differences (“DD”) to check BTs and SSTs for Cross-Platform Consistency • DDs cancel out/minimize effect of various systematic errors & instabilities in M-O arising from e.g. Errors and Instabilities in Reynolds SST & GFS Profiles; Missing aerosol; Possible systemic biases in CRTM’; Updates to ACSPO algorithm; Residual Cloud • Adding ERS/ENVISAT (A)ATSR, Metop-B AVHRR, MSG SEVIRI, and GOES-R ABI in MICROS is in preparatory stages • Adding SST optional bands is underway • MODIS: Ch22(3.96 μm), Ch23(4.06 μm), Ch29(8.52 μm) • VIIRS: M13(4.05 μm), M14(8.55 μm) DD’s @3.7 µm (Ref=Metop-A GAC) 4. Sensors Characteristics • AVHRRs, Terra/MODIS, NPP/VIIRS are consistent to within 0.15K. • Aqua MODIS out of family by 0.3K • Cal Change 7 Mar 2012 reset BT@M12 by +0.13K – well in family • NOAA16 unstable and out of family – calibration problems DD’s @11 µm (Ref=Metop-A GAC) • All AVHRRs and NPP/VIIRS are consistent to within 0.15K. • Terra and Aqua/MODIS out of family by 0.6K, due to suboptimal CRTM coefficients in vV2.02. • Cal Change 7 Mar 2012: BT@M15 by +0.14K; Now better in family • NOAA16 unstable and out of family – calibration problems 5. System Set-Up, Data Volumes, Processing Time DD’s @12 µm (Ref=Metop-A GAC) # of clear-sky ocean pixels and Processing Time for 24hrs of L1b data • All AVHRRs and NPP/VIIRS are consistent to within 0.15K. • Terra and Aqua/MODIS out of family by 0.3K, due to suboptimal CRTM coefficients in v2.02. • Cal Change 7 Mar 2012: BT@M15 +0.14K; Now better in family • NOAA16 unstable and out of family – calibration problems DD’s SST (Ref=Metop-A GAC) • All AVHRRs, MODISs and NPP/VIIRS are consistent to within 0.15K. • VIIRS Cal Change 7 Mar 2012: SST +0.15K; Out of family. • VIIRS SST went out of family 8 Mar • New regression coefficients imple-mented 3 May 2012 - back in family • NOAA16 unstable and out of family, due to unstable BTs • MICROS processes L1B data using the Advanced Clear-Sky Processor for Oceans, performs statistical analyses of BTs and SSTs & publishes on the Web. • MICROS is fully automated, with back-up processing enabled to improve stability 9. Conclusion 10. Future Work • MICROS monitors M-O biases in clear-sky BTs and SSTs over oceans in near-real time. It is an end-to-end system, currently functional with 4 AVHRR, 2 MODIS, and NPP/VIIRS • All M-O biases are warm, due to a combined effect of missing aerosols; using bulk SST (instead of skin); daily mean Reynolds SST (to represent night SST); & residual cloud • All MODIS BTs are biased warm by 0.3-0.6K (due to suboptimal CRTM coefficients) • MODIS 3.7µm: Terra/Aqua inconsistent by 0.3K, likely due to MODIS calibration problem • VIIRS BTs are consistent with AVHRR, especially after VIIRS IR Cal update in Mar 2012 • VIIRS SSTs are again consistent with AVHRR, after new regression coefficients implemented on 3 May 2012, in response to VIIRS Cal update on 7 Mar 2012 • Improve accuracy of MICROS DDs: Use more accurate first guess fields; Improve ACSPO cloud mask; Improve CRTM performance (especially daytime); Model diurnal variation (DV) in first-guess SST; Improve Sensor Radiances (Calibration, Spectral Response Functions) • Extend MICROS to Include Reflectance Bands • Aerosol Quality Monitor (AQUAM, http://www.star.nesdis.noaa.gov/sod/sst/aquam/) was set up to prepare for adding aerosol in CRTM • GOCART and NAAPS 3D aerosol fields have been selected as input to CRTM & AQUAM • Will use MICROS DDs to evaluate: CRTM in VIS; GOCART/NAAPS fields; Sensors calibration • Add MSG/SEVIRI, GOES-R ABI, ERS/ENVISAT (A)ATSR , Metop-B AVHRR in MICROS. Acknowledgement: This work is conducted under the Algorithm Working Group funded by GOES-R Program Office, NPOESS Ocean Cal/Val funded by IPO, and Polar PSDI, NDE and ORS Programs funded by NOAA. ACSPO is provided by NESDIS SST Team; CRTM is provided by NESDIS JCSDA. Thanks to John Stroup, Yury Kihai, Boris Petrenko, John Sapper, Mark Liu, Yong Chen, Paul Van Delst, David Groff, Fred Wu, Fangfang Yu, Fuzhong Weng, Changyong Cao, Tim Hewison, and Nick Nalli for advice and help. The views, opinions, and findings contained in this report are those of the authors and should not be construed as an official NOAA or U.S. Government position, policy, or decision. IEEE International Geoscience and Remote Sensing Symposium – Munich, Germany, 22-27 July 2012 Correspondence: Alex.Ignatov@noaa.gov, Tel: 301-763-8102 x190, Fax: 301-763-8572