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MODAPS PCR 25-004

PCR Number	25-004
Date	2025-06-02
Initiator	Zhuo (Julie) Wang and Sudipta Sarkar
Abstract	PGE85 6.1.4 C61 Specific Algorithm Change/Improvements: 1. A new release of C61 version of PGE85, v6.1.4. 2. The new PGE85 contains revisions: Addressed run-time anomalies stemming from undefined behaviors such as underflow and accessing out-of-bound elements in an array; Integrated auto-formatting tools. Fixes for compatibility for MODAPS Ubuntu system: -(1) underflow issue in tauwtr (fm_tran_modis101.f) -(2) out of bound indexing of std_doy/leap_doy in run_forward_model.f -(3) reading Reynolds SST file in get_ancillary_fm.f by adding a "call exit(1)" if the sst_success is failed 3. The new Clear Sky Radiance Bias file is used for MOD_PR06CT development.
Problem Statement	While preparing to port C6.1 PGE85/MOD_PRCSRMG and MOD_PRCSRG to a C7 version the SSTG team identified that the PGE was no stable and as a result did not run consistently when executed multiple times over the same input granules. Findings were shared with Wisconsin Cloud Team who fixed the issues and delivered code revisions for PGE85 C6.1. SSTG integrated and tested the changes in PGE85 6.1.4-0 which was then used in science tests and reviews by Science team and LDOPE. LDOPE and science team compared 8-day test results of PGE85 v6.1.4-0 with C6.1, and confirmed that the PGE85 C6.1 Ubuntu test was successful. The observed differences are within the limits of data precision and PGE85 6.1.4 was created from v6.1.4-0.
Description of Change	C61 Specific Algorithm Change/Improvements: 1. A new release of C61 version of PGE85, v6.1.4. 2. The new PGE85 contains revisions: Addressed run-time anomalies stemming from undefined behaviors such as underflow and accessing out-of-bound elements in an array; Integrated auto-formatting tools. Fixes for compatibility for MODAPS Ubuntu system: -(1) underflow issue in tauwtr (fm_tran_modis101.f) -(2) out of bound indexing of std_doy/leap_doy in run_forward_model.f -(3) reading Reynolds SST file in get_ancillary_fm.f by adding a "call exit(1)" if the sst_success is failed 3. The new Clear Sky Radiance Bias file is used for MOD_PR06CT development.
Products Affected	It will generate MxDCSRFM, MxDFMHDR, MxDCSR_G, MxDCSR_D, MxDCSR_8, and MxDCSR_B products for Terra and Aqua.
Software Affected	PGE85 6.1.4
Processing String to Receive the Change	Terra Forward Processing. Terra Reprocessing. Aqua Forward Processing. Aqua Reprocessing.
Downstream Product Effects	C61 products: MxDCSRFM, MxDFMHDR, MxDCSR_G, MxDCSR_D, MxDCSR_8, and MxDCSR_B.
Data Granules to be Used for Science Testing	PGE85 v6.1.4 for C6.1 Ubuntu test is successful. The observed differences between AS2012 and the operational C6.1 are within the limits of data precision.
Justification	For consistent execution of PGE85 when same version is rerun for any reason, which will insure that consistent outputs are generated when no input data has changed. It will also insure better quality outputs for initial runs.
Effective Date for Implementation of Change	The PGE85 v6.1.4 was placed in forward processing, starting 2025-06-02.
Status	Sadashiva Devadiga approved 06/09/2025. Sudipta Sarkar implemented on 06/02/2025.