Meteorology reprocessing

Wednesday, 7 January 2015

Xiaofang Zhu, Global Science and Technology, inc, College Park, MD; and E. Maturi, J. Mittaz, A. Harris, C. M. Eakin, A. Ignatov, and X. Zhou

Efforts are being carried out at NOAA/NESDIS/STAR to reprocess the global geostationary and polar orbiting satellite sea surface temperature (SST) data using state-of-the-art NOAA operational algorithms from 2004 to present. For geostationary data, the latest operational algorithm calculates SST by utilizing a new physical retrieval scheme based on modified total least squares (MTLS, Koner et al., 2014) and a probabilistic (Bayesian) approach for cloud masking (Merchant et al., 2005). The geostationary satellites being reprocessed include GOES (GOES-9,10, 11,12,13 &15) satellites from NOAA, MTSAT (MTSAT1-R and MTSAT-2) satellites from Japan Meteorological Agency (JMA), and also Meteosat (8, 9 and 10) from Eumetsat during the 10-year period. The total raw data volume for geostationary sensors that will be reprocessed is ~200TB. These provides a near complete coverage of the tropics and mid-latitudes with at least hourly time resolution. For the polar orbiting satellites, AVHRR and METOP data are being reprocessed using the Advanced Clear-Sky Processor for Oceans (ASCPO) (Petrenko et al., 2010). The geostationary and polar data are then combined to generate the Geo-Polar blended 5-km SST daily global SST analysis. All level-2 and level-4 products are being validated against global drifting buoy and tropical mooring data.

A key use of the 10-year time series of daily 5-km SST analyses will be the generation of an updated climatology for NOAA Coral Reef Watch's operational global coral bleaching monitoring and prediction products (Strong et al., 2004). The current operational SST climatology is based on a twice-weekly 50-km AVHRR SST analysis that was developed in the 1980s, and current bleaching thresholds have been derived using this heritage data. The 5-km SST analysis will provide thermal stress information with significantly improved quality and much better spatial coverage, which is especially critical for fringing reefs. Hence it is necessary to rederive the climatological thresholds using the reprocessed SST analysis, upon which the new anomaly products will be based. The reprocessed geostationary and polar data themselves will provide a 10-year long global SST record with consistent and up-to-date algorithms, which will be useful for other long-term trend research questions and process studies. In particular, the reprocessed geostationary data will provide a unique record of the diurnal cycle of sea surface temperature over the most recent decade.