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MODAPS PCR 20-021

PCR Number	20-021
Date	2020-09-22
Initiator	Jim Ray
Abstract	PGE199 1.0.8 -- 1. Updated LM (RealTimeDelay of 'DAYS=2' for M1_GAC AVHRR inputs)(Delay running PGE199 -- run PGE199 on data-day X on actual-day X+2) 2. Updated PGEVER to '1.0.8' in PGE199/GAPS/src/gaps_HDF.c
Problem Statement	MODAPS does not receive the full set of MetOp GAC files for a given day, until well into the first half of the following day. But the operational version of PGE199 (V1.0.7) was not set up to wait for the arrival of the full set of GAC files and would start with incomplete GAC files, resulting in persistent gaps in the global coverage. While the PGE could be manually forced to run at 2+ days of delay, a proper fix to the loader module was required to automate this process.
Description of Change	A new version of PGE199 (V1.0.8) was delivered, with updates to the loader module, allowing it to delay the processing of the current day by at least two days, to ensure the arrival and staging of the full set of GAC files.
Products Affected	AVHRR Version 5 LTDR products.
Software Affected	PGE199 1.0.8
Processing String to Receive the Change	NOAA-N* Reprocessing. MetOp-B Reprocessing. MetOp-B Forward Processing. MetOp-C Reprocessing. MetOp-C Forward Processing.
Downstream Product Effects	None
Data Granules to be Used for Science Testing	A science test was not deemed necessary for this change as no science algorithm change was carried out.
Justification	Enable the full global coverage of V5 LTDR products, derived from AVHRR onboard the MetOp-B platform, by forcing the PGE to run only after the arrival/staging of the full set of input M1 GAC files for a given day.
Effective Date for Implementation of Change	This PGE199 V1.0.8 will be used for LTDR V5 forward processing, using inputs from MetOp-B, starting September 16 of 2020.
Status	Major algorithm development completed. Sadashiva Devadiga approved on 09/21/2020. Gang Ye approved on 09/21/2020.