MODAPS PCR 18-005
| PCR Number | 18-005 |
|---|---|
| Date | 2018-09-25 |
| Initiator | Glynn C. Hulley |
| Abstract | PGE116 v6.0.68 - Assign fill values to all pixels for LST where the input L1B emissive band values are invalid or bad. |
| Problem Statement | The L2 LST MOD21 product from C6 operational reprocessing of Terra MODIS year 2000 data contained stripes of anomalous LST values but in the valid range and with QA flagged as LST not retrieved for reasons other than cloud. Source of the problem is striping in the thermal bands caused by poor performance of thermal bands of Terra MODIS during the early period of the mission prior to data day 2000305. |
| Description of Change | Assign fill values to all pixels for LST where the input L1B emissive band values are invalid or bad. |
| Products Affected | Daily L2 LST (MOD21/MYD21) |
| Software Affected | PGE116 v6.0.68 |
| Processing String to Receive the Change | Terra and Aqua Forward Processing, Terra and Aqua Reprocessing |
| Downstream Product Effects | Daily L3 LST (MOD21A1D/N, MYD21A1D/N), 8-day LST (MOD21A2/MYD21A2) |
| Data Granules to be Used for Science Testing | Several science tests have been carried out to asses and confirm the required fixes. |
| Justification | Operational C6 reprocessing of MOD21 was halted pending quick fix to the issue. Without the recommended fix the product couldn’t have been used correctly as largely incorrect values were being retrieved for LST and the retrievals were not being correctly flagged. This fix should address the issue by not retrieving the LST value for invalid input L1B TB values and then flagging them as not retrieved due to bad input L1B. |
| Effective Date for Implementation of Change | Completed. |
| Status | Major algorithm development completed. Chris Justice approved 9/26/2018. Sadashiva Devadiga approved 09/26/2018. Gang Ye approved on 09/27/2018. |
