MODAPS PCR 20-012
| PCR Number | 20-012 |
|---|---|
| Date | 2020-07-07 |
| Initiator | Sudipta Sarkar |
| Abstract | PGE24 v6.1.3 -- 1. Changed "if(all->wData->HD_snow_qa[row][col] != 255)" to "if(all->wData->HD_snow_qa[row][col] < 2)" 2. Changed "char reprocessingactual;" to "char *reprocessingactual |
| Problem Statement | The operational PGE24 that was being used in the C61 reprocessing, was failing for certain data days as it was not able to handle incorrect data values in one of the dataset (Snow_BRDF_Albedo) from the input intermediate file, MCD43T2. |
| Description of Change | PGE24 V6.1.3 was submitted to address the issue of encountering occasional invalid data values in the intermediate input files of MCD43T1/T2. In this revised version, the check for valid snow values, has been made more restrictive to avoid the possibility of including any invalid snow values that may have been produced in the MCD43T2 files because of some corruption. |
| Products Affected | MODIS C6 Land L3 GIBS products |
| Software Affected | PGE24 6.1.3 |
| Processing String to Receive the Change | Terra and Aqua Forward Processing. Terra and Aqua Forward Reprocessing. NRT |
| Downstream Product Effects | None |
| Data Granules to be Used for Science Testing | No science test is deemed to be necessary as the change is very minor and has been tested thoroughly through two unit tests that covered one of the C61 failed case and another nominal case, just to confirm that no other inadvertent science changes were made. |
| Justification | The intermediate MCD43T1/T2 files, produced by the operational PGE23 (tiled BRDF) contained some corrupt data values for some of the datasets causing failure in the downstream PGE24 (CMG BRDF). This happened for two data days in the on-going C61 reprocessing, where the Snow_BRDF_Albedo from the MCD43T2 was found to contain an unexpected value of ?129?, instead of the expected range of ?0-1?. Hence the C61 PGE24 was fixed to make the check for valid snow values, more restrictive. This change was submitted as PGE24 V6.1.3 |
| Effective Date for Implementation of Change | As soon as possible in the leading edge of C61 re-processing as of drafting this PCR (07/07/2020) |
| Status | Major algorithm development completed. Chris Justice approved on 07/28/2020. Sadashiva Devadiga approved on 07/23/2020. Gang Ye approved on 07/27/2020. |
