MODAPS PCR 22-014
| PCR Number | 22-014 |
|---|---|
| Date | 2022-09-20 |
| Initiator | Praveen Noojipady and Sudipta Sarkar on behalf of P.I. Robert Sohlberg |
| Abstract | PGE61 6.1.4, PGE61M 6.1.4, PGE61T 6.1.4 C61 Specific Algorithm Change/Improvements: - Update MOD_PR44B3/MOD44B3.c MOD_PR44B3/make_grid.c to update valid_range from 253 to 100 for sds Percent_Tree_Cover, Percent_NonTree_Vegetation, Percent_NonVegetated. - Update MOD_PR44B3/MOD44B3.c small change that populates the outputs with fill values when there are fill values in the input files. - Changed DFACC_RDWR to DFACC_READ in MOD_PR44B3/MOD44B3.c to read MOD44W input. - Added the water value as 200 and the scale factor as 0.01 to the metadata of the appropriate layers. - Removed mapi usage and used latest shared src. |
| Problem Statement | Update the MODAPS C6 PGE for processing the Collection 6.1 (C61) global MODIS Vegetation Continuous Fields (VCF), MOD44B and reprocess the mission period data using the C61 PGE. |
| Description of Change | Several science and production rule changes were made as part of this C61 VCF processes, including: 1. Change in retrieval pattern of VCF over certain northern high latitude areas - in C61, these areas are not retrieved anymore due to sparseness of training samples and are populated as FillValues. 2. Added certain SDS level attributes like addition of water value of 200 and scale factors, for different datasets. 3. Updated the valid_range for certain SDS level attributes. 4. Made some production rule changes to leverage libraries and shared sources from the GitLab repository. |
| Products Affected | Yearly C61 L3 VCF product, MOD44B |
| Software Affected | PGE61 6.1.4, PGE61M 6.1.4, PGE61T 6.1.4 |
| Processing String to Receive the Change | Terra Forward Processing. Terra Reprocessing. |
| Downstream Product Effects | None |
| Data Granules to be Used for Science Testing | A series of science tests carried out at MODAPS and test data reviewed by LDOPE and science team. Confirmed all production rule and science changes using the science test data in AS1885, AS1887, AS1904, and AS1916. The outputs from this test fully assessed and PGE approved by LDOPE and the science team. |
| Justification | Improvements or change in the C61 product compared to the product from the prior C6 is from changes and enhancements to the calibration approach used in generation of the Terra MODIS L1B products. The C61 VCF was produced with the same training data as the C6 version. One major change in C61 VCF is that areas with sparse vegetation are not retrieved and are populated with fill value of "0" or "100", as applicable. |
| Effective Date for Implementation of Change | MODAPS was requested to start the reprocessing of the C61 VCF products, with all the changes mentioned herein, as of 09/27/2022. |
| Status | Major algorithm development completed. Sadashiva Devadiga approved on 10/13/2022. Sudipta Sarkar approved on 10/13/2022. |
