MODAPS PCR VNP 21-012
| PCR Number | VNP 21-012 |
|---|---|
| Date | 2021-08-18 |
| Initiator | Carol Davidson |
| Abstract | PGE600 2.0.2 (CR generation): 1. Update to num_day_375m_rows.c to use both sensor_mode flags and solar zenith angle to detect day granules. PGE620 2.0.8 (Swath to tile mapping): 1. Updated day_night_rows.exe to remove day & night mixed rows by solar zenith angle. 2. Added check to PGE620*_LoaderModule.pl to see if granule to be processed is in the DataHiddenFromProduction table, and if it is, go to NoRun. 3. Changed line with P=V|$tkver to be within double quotes not single, per request from MODAPS team. |
| Problem Statement | GIBS images of NRT VIIRS Corrected Reflectance (CR) and I5 band generated by the ops PGE620 and PGE600 contained checkerboard patterns, towards the polar day/night transition areas. |
| Description of Change | |
| Products Affected | S-NPP and J1 CR and Band I5 GIBS products from NRT and OPS stream respectively for S-NPP and J1 VIIRS. This is a fundamental change to the day/night delineation approach and impacts all S-NPP and J1 L1 images |
| Software Affected | PGE600 2.0.2; PGE620 2.0.8 |
| Processing String to Receive the Change | NRT |
| Downstream Product Effects | None |
| Data Granules to be Used for Science Testing | Science tests have been carried out for J1, extensively from NRT4 and verified through LDOPE internal assessment and by the WorldView team. |
| Justification | 1. These changes will enable GIBS to use better looking imageries derived from use of NASA L1B. 2. Make the CR and I5 imageries consistent and follow the similar method for both. 3. Use a combination of scan_mode day/night flag and the sensor zenith to mitigate any possible admixture of day and night observations. |
| Effective Date for Implementation of Change | PGE600 V2.0.1, PGE603 V2.0.1 and PGE620 V2.0.4 was put in nrt3/4 for S-NPP on 02/26/2020. |
| Status | Major algorithm development completed. Sadashiva Devadiga approved 08/18/2021. Gang Ye approved on 08/23/2021. |
