Data collection for the International Satellite Cloud Climatology Project (ISCCP) began in July 1983. Since then data from 28 satellites have been incorporated into the ISCCP B1 data record.
Data are collected at Satellite Processing Centers (SPCs) around the world. The centers receive full resolution data for the satellite for which they are responsible to provide data. The data are sampled to approximately ~10km and 3-hourly resolution and sent to the ISCCP Central Archive (NCDC) for storage. The SPCs further subsample the data to approximately 30km resolution, sending that data to the ISCCP processing center (NASA/GISS). GISS then processes the B2 data to B3 data, from which the ISCCP cloud products are derived.
The ISCCP B1 data figuratively sat on a shelf at NCDC until data rescue efforts began in 2003. By then the data were, for most part, unuseable. The formats were unknown and read/write routines were non-existent. Over the span of two years, NCDC worked toward the ability to read and navigate all B1 data. Along the way, gaps in the inventory were discovered and subsequently filled by SPCs and NCDC. The B1 data rescue was successful and has resulted in the use of ISCCP B1 data in numerous scientific endeavors.
Since the successful rescue of the B1 data, efforts have included recreating B1 data for dates prior to the start of ISCCP data collection (July 1, 1983). This included retrieving data from CLASS, subsampling the full resolution data to the B1 level, then checking the quality using B1 processing algorithms. EUMETSAT (Europe) and JMA (Japan) kindly performed similar steps providing early B1 data for Meteosat-2 and GMS-1. The result of the backfilling extended the beginning of ISCCP B1 coverage from July 1983 to as early as 1978 for some satellites.