Upgraded GEOS FP-IT System Starts Real-Time Data Delivery


The current version of the GEOS FP-IT system (GEOS-5.9.1) has been in production since March 2013, providing GEOS-5 assimilation products in near-real time to NASA instrument teams as well as other research users. These products are delivered through the GES DISC to the subscribed users. The GEOS data assimilation system has evolved considerably since 2013, incorporating many scientific improvements, that result in improved assimilated datasets, and technical advances that allow the system to run more efficiently on the NCCS computing platforms.

In consultation with the instrument teams that use the GEOS FP-IT datasets, GMAO has upgraded the data assimilation system to a later version, GEOS-5.12.4. This is the same system that is used to generate the MERRA-2 reanalysis datasets, which were released in January 2016 for public access. For more details of MERRA-2 products, please visit https://gmao.gsfc.nasa.gov/reanalysis/. The GEOS FP-IT data differ from MERRA-2 in two ways: some of the observations assimilated in MERRA-2 are not included in GEOS FP-IT and the output data collections are customized for the users of the products.

Since the GEOS-5.12.4 includes significant upgrades to the GEOS-5.9.1 system, the data reprocessing was planned to provide a consistent dataset covering the EOS satellite era, beginning in January 2000. The reprocessing plan was developed in a consultation with the instrument teams. On the basis of these discussions, a decision was made to exclude some of the input observations, such as the Microwave Limb Sounder ozone and temperature retrievals used for MERRA-2, from the GEOS FP-IT processing. The product file specification remains the same as that for GEOS-5.9.1 except for the change of the first node of all filenames from ‘DAS’ to ’GEOS‘ and the fifth node from 'GEOS591' to 'GEOS5124'. The file specification document (Lucchesi, 2015) is available as Office Note #2 (Version 1.4) on the publications section (https://gmao.gsfc.nasa.gov/pubs/) of the GMAO's web site.

The reprocessing started in November 2015 and was conducted in three streams, spanning the following time segments:

Stream #1: January 2000 – December 2003 Stream #2: January 2004 – December 2011 Stream #3: January 2012  onwards.

Stream #3 reprocessing caught up to real time in mid-August 2016. GMAO plans to start the near real time delivery of the GEOS-5.12.4 assimilated datasets to the DAAC September 1, 2016. All the data from Stream #1 have been already been delivered to the DAAC. Delivery of the Stream #2 data will be completed in late September 2016, at which point the GEOS FP-IT user community will have an assimilated dataset that spans the period beginning on January 1, 2000, up to the current date.

The current GEOS-5.9.1 FP-IT data processing and delivery will continue through January 2, 2017, providing a four-month overlap period to facilitate the FP-IT data users’ transition to the GEOS-5.12.4 data products.

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