MODAPS PCR 15-009
| PCR Number | 15-009 |
|---|---|
| Date | 2015-04-07 |
| Initiator | Zhuosen Wang |
| Abstract | PGE23 v6.0.15. Exclude reflectance observations flagged as dead detectors from processing by checking for individual band quality flag in the input daily surface reflectance product. |
| Problem Statement | Daily BRDF-Albedo tiled product generated by the on-going C6 reprocessing is contaminated by observations from dead and noisy detectors. |
| Description of Change | Changes to PGE23 toa. Use the individual band QA flag in the input surface reflectance product to determine the band quality and process the bands as opposed to using the summary MODLAND QA bits to process all bands.b. Exclude reflectance observations flagged as dead detectors from processing by checking for individual band quality flag in the input daily surface reflectance product |
| Products Affected | MCD43A1, MCD43A2, MCD43A3, MCD43A4 |
| Software Affected | PGE23 v6.0.15 |
| Processing String to Receive the Change | Terra Reprocessing and Aqua Reprocessing |
| Downstream Product Effects | None. |
| Data Granules to be Used for Science Testing | Process 8-day period starting data day 2001193 generating the BRDF-Albedo product for all land tiles for each of the data day using the 16-day input from the C6 archive.2010-059 |
| Justification | Using the individual band quality will let the algorithm process one or more bands flagged as good quality instead of processing all bands or none while using the summary MODALND QA bits. Observations from dead and noisy detectors could have small values in the valid range for reflectance in the input daily surface reflectance product. These observations, if not removed through proper check of quality flags, could be used as good observations thereby contaminating the retrieved BRDF/Albedo. These contaminated retrievals could appear as stripes in the output BRDF/Albedo product. Putting this change for operational processing at an arbitrary data day in the on-going C6 reprocessing could potentially result in temporal inconsistency in the records. Hence re-reprocessing of back dates is requested. |
| Effective Date for Implementation of Change | Completed. |
| Status | Major algorithm development completed. Michael King approved on 04/23/2015. |
