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MODAPS PCR VNP 23-007

PCR Number	VNP 23-007
Date	2023-11-03
Initiator	Carol Davidson
Abstract	PGE510 2.0.13 The PGE510 V2.0.13 bit-mask definitions were corrected to set the the QA bits properly. In addition, the following maintenance revisions were made in this update: corrected several malloc() calls for which the return value was cast to the incorrect data type; replaced malloc() with calloc() in main processing module to ensure that all internal bit fields were initially clear; increased netCDF compression level to reduce final product size; corrected bug in input module that could potentially use an uninitalized array to check for invalid reflectance values; minor changes to "fire mask" data-set legend for clarity. Changes to the science code were made by the current PI Louis Giglio after review of C2 datasets. Changes to PGE510.pl to correct missflagging of outputs implemented by SSTG.
Problem Statement	Errors in several bit-mask definitions caused multiple bits in the VNP14IMG product QA layer to be set incorrectly for daytime pixels. Additionally, there was a flaw in the PGE510.pl causing miss-flagging of products as "bad" and for them to fail to archive properly.
Description of Change	The PGE510 V2.0.13 bit-mask definitions were corrected to set the the QA bits properly. In addition, the following maintenance revisions were made in this update: 1) corrected several malloc() calls for which the return value was cast to the incorrect data type; 2) replaced malloc() with calloc() in main processing module to ensure that all internal bit fields were initially clear; 3) increased netCDF compression level to reduce final product size; 4) corrected bug in input module that could potentially use an uninitalized array to check for invalid reflectance values; and 5) minor changes to "fire mask" data-set legend for clarity. Changes to the science code were made by the current PI Louis Giglio after review of C2 datasets. Changes to PGE510.pl to correct missflagging of outputs implemented by SSTG.
Products Affected	S-NPP and J1 375m active fire products in NRT and standard processing: VNP14IMG, VNP14IMG_NRT, VJ114IMG, VJ114IMG_NRT.
Software Affected	PGE510 2.0.13
Processing String to Receive the Change	S-NPP Forward Processing. S-NPP Reprocessing. J1 Forward Processing. J1 Reprocessing. NRT
Downstream Product Effects	None
Data Granules to be Used for Science Testing	Science tests have been carried out for both S-NPP and J1, using PGE510 (V2.0.13) and all results have been assessed by LDOPE and communicated to the science team.
Justification	Change causes a discontinuity in the collection QA flags and therefore all of C2 should be reprocessed with this version. In addition, many pre-change QA flags were not set correctly and hence defeated the purpose of having the flags in the product.
Effective Date for Implementation of Change	PGE510 V2.0.13 was put in nrt3/4 and C2 leading edge for J1 and S-NPP on 11/01/2023.
Status	Major algorithm development completed. Sadashiva Devadiga approved 11/26/2023. Carol Davidson implemented 11/01/2023.