92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012: 4:45 PM
NPP VIIRS SST Algorithm and Cal/Val Activities At NOAA/NESDIS
Room 343/344 (New Orleans Convention Center )
Alexander Ignatov, NOAA/NESDIS, Camp Springs, MD; and X. Liang, P. Dash, J. Stroup, Y. Kihai, B. Petrenko, F. Xu, J. Sapper, R. Arnone, S. Jackson, and P. DiGiacomo

The first US satellite in the Joint Polar Satellite System (JPSS) series, NPP, is scheduled for launch in October 2011. It will carry a new Visible/Infrared Imager/Radiometer Suite (VIIRS) instrument onboard. VIIRS calibrated and geo-located Sensor Data Records (SDR; known as L1b data for AVHRR and MODIS) will be produced by the Interface Data Processing Segment (IDPS). From SDRs, a number of Environmental Data Records (EDR; VIIRS L2 products) will be generated. The Sea Surface Temperature (SST) EDR is one of the four key performance parameters for JPSS. The initial EDR algorithms, including SST and VIIRS Cloud Mask (VCM), have been developed by the Northrop Grumman Aerospace Systems (NGAS) and adopted in the IDPS.

SDR and EDR algorithms and Cal/Val activities are coordinated by the JPSS Program Office. NESDIS' Center for Satellite Applications and Research (STAR), jointly with NAVOCEANO and U. Miami, have been involved in JPSS SST development from the beginning of the JPSS program, as advisors to NGAS and as members of the Ocean Cal/Val Team. Recently, STAR was additionally charged with algorithm support responsibilities, which are now executed in conjunction with the Cal/Val activities. Also, the STAR SST Team has been involved in the NPP Data Exploitation (NDE) Project at NOAA, and in the GOES-R SST development funded by the GOES-R Program Office.

In preparation for NPP launch, the STAR/OSPO SST Team has developed a major Level 1 processing system (ACSPO) and three near-real time online tools (SQUAM, iQuam, and MICROS) which will continue to be employed during the JPSS era:

1) Advanced Clear Sky Processor for Oceans (ACSPO; ftp://www.star.nesdis.noaa.gov/pub/sod/osb/aignatov/ACSPO/) system was developed to generate clear sky sensor radiances (CSR) over oceans, from which SST and Aerosol products are derived. ACSPO has been operational at NESDIS since May 2008, processing AVHRR GAC data from NOAA-16, -17, -18, -19, and Metop-A and FRAC data from Metop-A. Currently ACSPO is being tested with MODIS-Terra and Aqua data, and with VIIRS proxy SDR stream. Note that ACSPO substantially differs from IDPS processing by using the Community Radiative Transfer Model (CRTM) in conjunction with first guess SST and upper air fields, to more accurately specify the clear-sky mask, and to improve SST retrievals over the regression approaches adopted in IDPS.

2) The SST Quality Monitor (http://www.star.nesdis.noaa.gov/sod/sst/squam/) currently monitors several SST Level 2 (L2) products from AVHRR, in near-real time (NRT). Work is underway to include two MODIS L2 products in SQUAM: MO(Y)D28 and ACSPO SST, and two L2 SST products from VIIRS: EDRs generated by IDPS, and ACSPO SST. All L2 products are monitored in SQUAM for stability and self- and cross-consistency, against global L4 analysis fields (e.g., Reynolds, OSTIA), and are validated against quality controlled (QC) in situ SST data generated by the in situ Quality Monitor (iQuam).

3) In situ Quality Monitor (iQuam; http://www.star.nesdis.noaa.gov/sod/sst/iquam/) NRT tool performs three functions: a) quality control (QC) of in situ data; b) monitoring QCed data online; and c) serving QCed data to outside users. Output from iQuam is used as input to SQUAM, for consistent validation of various satellite L2 products.

4) A NRT web-based Monitoring of IR Clear-sky Radiances over Oceans for SST (MICROS; http://www.star.nesdis.noaa.gov/sod/sst/micros/ ) monitors clear-sky brightness temperatures (BT) used as input to SST algorithms against global Community Radiative Transfer Model (CRTM) simulations, in conjunction with first guess SST and atmospheric fields. MICROS monitoring will be used to monitor BTs associated with SST, and to provide feedback to the SDR Team on sensor performance.

Status and launch readiness of these tools, and testing using heritage (AVHRR, MODIS) and VIIRS proxy SDR data streams, are discussed.

The following SST activities will be performed at NEDSIS following the NPP launch 1) Once VIIRS SDRs become available: Collect approximately 1 month of global data. Apply ACSPO to collect data for subsequent calculation of SST coefficients. Fine-tune ACSPO clear-sky mask. 2) Generate ACSPO heritage line of products: clear-sky BTs, SSTs and Aerosols. 3) Add ACSPO VIIRS CSRs to MICROS and evaluate against CRTM simulations. Check for stability/consistency with AVHRR & MODIS CSRs. 4) Add ACSPO VIIRS SST to SQUAM. Evaluate against L4 SST, validate against in situ data from iQuam. Check for stability and consistency with AVHRR and MODIS SSTs. 5) Once IDPS SST EDR becomes available: Add to SQUAM. Evaluate against L4 SST. Validate against in situ data from iQuam. Check for stability and consistency with AVHRR and MODIS SSTs, and ACSPO VIIRS SST. 6) If any anomalies and out-of-family patterns are observed in VIIRS CSRs, provide feedback to VIIRS SDR Team and collaborate to resolve. 7) If unrealistic cold anomalies observed in IDPS SSTs, report to VIIRS Cloud Mask (VCM) Team and collaborate to resolve; if in ACSPO SST work in STAR to resolve. 8) Work iteratively with SDR and VCM Teams, and NGAS SST Team to improve the quality of IDPS and ACSPO clear-sky BTs and SST products.

NESDIS SST activities are closely coordinated with NAVO and U. Miami activities.

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