MODAPS PCR 14-003
| PCR Number | 14-003 |
|---|---|
| Date | 2014-01-08 |
| Initiator | Bill Ridgway |
| Abstract | To implement major updates in PGE04 v6.0.36. |
| Problem Statement | Major updates were implemented as described below. |
| Description of Change | The MODIS aerosol product continues to include results from a Dark Target (DT) algorithm applied over ocean and dark land (e.g., vegetation) targets and a Deep Blue (DB) algorithm originally developed for bright reflecting surfaces (e.g., deserts). Both results are provided on a 10x10 pixel scale (10 km at nadir).Based on C5 validation studies, a number of SDSs have been deleted from the DT product (Angstrom_Exponent_Land, Optical_Depth_Small_Land, etc.) while a number of SDSs have been renamed or added. The C6 DT algorithm provides a new 3 km spatial resolution SDSs intended for the air quality community.The DB algorithm expanded coverage to include vegetated regions in addition to bright targets, using NDVI information in addition to a precalculated surface reflectance database. The product now includes retrieval confidence and usefulness QA assignments.In addition to the separate DT and DB retrievals, the C6 product now provides a merged Science Data Set (SDS) that combines both types of retrievals (SDS name AOD_550_Dark_Target_Deep_Blue_Combined). The SDS uses a combination of scene NDVI and retrieval Quality Assessment (QA) assignments to select one of the retrievals (if any) or an average of the two retrievals. Ocean retrievals from the DT algorithm are also provided if they have a sufficiently high retrieval QA value. |
| Products Affected | MYD04_L2, MYD04_3K (new) |
| Software Affected | PGE04 v6.0.36Recipe: [AP]M1M_C6_A1m 6.0.122 |
| Processing String to Receive the Change | Aqua Forward, Aqua Reprocessing |
| Downstream Product Effects | Subset products (PGE83), Browse products (PGE89, PGE108) and Level 3 MYD08_*3 products. |
| Data Granules to be Used for Science Testing | A long series of science tests were required to develop the new algorithm and check for sensitivity to L1B calibration.2010-059 |
| Justification | Provides 3km resolution DT product over land, DB product over vegetated surfaces. Improves product quality over land and ocean surface. |
| Effective Date for Implementation of Change | Jan 1, 2014 for Aqua forward reprocessing. Reprocessing for the full Aqua mission. |
| Status | Major algorithm development and testing completed. Steve Platnick approved on 1/8/2014. Michael King approved on 2/7/2014. |
