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MODAPS PCR 25-001

PCR Number	25-001
Date	2025-01-10
Initiator	Sudipta Sarkar on behalf of Gary Lin (Geolocation) and Jack Ziong, Amit Angal/Kevin Twedt (MCST)
Abstract	PGE01 7.0.13, PGE02 7.0.20_0 (Terra), PGE02 7.0.19_0 (Aqua), PGE93 7.0.3 This PCR is addendum to the previous PCR24-004 and the updates include: 500m Geolocation Layers: New 500m latitude/longitude layers were added to the L1/Geolocation product (MxD03). The PGE01 will retain the 1km and 500m geolocation and height layers. Removal of Native Resolution Geolocation Layers: Updated PGE02 to remove native resolution geolocation layers from L1Bs that was previously added. The C7/L1B outputs will resemble the C61 version.
Problem Statement	Generate improved version of the MODIS Collection 7 (C7) L1 Geolocation and calibrated Top of Atmosphere (TOA) products, in the first phase of C7 L1 reprocessing, from Terra Beginning of Mission (BOM) in 2000 to end of 2021.
Description of Change	This PCR is addendum to the previous PCR24-004 and the updates include: 500m Geolocation Layers: New 500m latitude/longitude layers were added to the L1/Geolocation product (MxD03). The PGE01 will retain the 1km and 500m geolocation and height layers. Removal of Native Resolution Geolocation Layers: Updated PGE02 to remove native resolution geolocation layers from L1Bs that was previously added. The C7/L1B outputs will resemble the C61 version.
Products Affected	C7 Geolocation (MxD03), Calibrated TOA (MxD02) and all downstream land and atmosphere products.
Software Affected	PGE01 7.0.13, PGE02 7.0.20_0 (Terra), PGE02 7.0.19_0 (Aqua), PGE93 7.0.3
Processing String to Receive the Change	Terra Reprocessing. Aqua Reprocessing.
Downstream Product Effects	All C7 MODIS Land + Atmosphere products.
Data Granules to be Used for Science Testing	Series of science tests were run in AS 1990, 1993, and 1999 to confirm all the changes made to the C7 PGE01 and PGE02, and associated LUTs, and validate their impacts on the L1B products.
Justification	The native 250m/500m geolocation layers will not be propagated to downstream L1Bs (MxD02*)/L2s due to storage limitations. Hence, the C7/MxD03 products will now have new 500m geolocation (lat/long) layers in addition to the 1km layers. The V-interface within API-Trans was revised to fix the issue in the VSread() and VSwrite() functionality for HDF5 that was creating a 30m scan offset error in the C7 MOD03 for Terra between later part of 2000 and early part of 2001.
Effective Date for Implementation of Change	The PGEs and Recipes mentioned here will be used to initiate the C7 L1 reprocessing, for the 2000 - 2015 period, starting the week of January 13th, 2025.
Status	Gary Lin approved 01/13/2025, Sadashiva Devadiga 01/13/2025, Miguel Roman approved 01/13/2025, Sudipta Sarkar implemented on 03/25/2025