MODAPS PCR 18-003
| PCR Number | 18-003 |
|---|---|
| Date | 2018-09-11 |
| Initiator | Glynn C. Hulley |
| Abstract | PGE116 v 6.0. 67 - Use of new shared BROWSE code (v6.0.50) with updated color LUT/Legend. PGE130 v6.0.3 - Use of PGE12/MOD_PRMGR/HISTORY.txt (v6.0.21); Fixed the data type, units and valid range for MOD21 dataset "PWV" in lh2g_lst21.h and lhdf_lst21.h files to reflect the new PWV sds in MOD21 L2. PGE131 v6.0.16 - Slight change to the QA legend to match the UG. PGE136 v6.0.10 - Change for the MODLAND QA bit legend in MOD21A2 products to match with the UG. |
| Problem Statement | The C6 MxD21 suite of LST products contained large temperature/emissivity errors from inadvertent turning off of the Water Vapor Scaling (WVS) model component in the processing code. Processing and distribution of product was discontinued pending fix to the processing software. Further examination of the product revealed product issues related to incorrect implementation check for cloud cover, incorrect or missing science data attributes and incorrect color lookup table used to generate the browse image product. |
| Description of Change | - Assign correct LUN to the “PWV_THRESH†parameter in PGE116 PCF file to turn ON the WVS model component in the processing code - Code change to correctly identify the cloud flag in the input cloud mask product - Update code to correct the missing and wrong SDS attributes - Fix color scale and legend issue in the shared browse code |
| Products Affected | L2 daily LST (MOD21/MYD21), L3 daily LST (MOD21A1D/N, MYD21A1D/N), 8-day LST (MOD21A2/MYD21A2) |
| Software Affected | PGE116 v6.0.67, PGE130 v6.0.3, PGE131 v6.0.16, PGE136 v6.0.10 |
| Processing String to Receive the Change | Terra and Aqua Forward Processing, Terra and Aqua Reprocessing |
| Downstream Product Effects | None |
| Data Granules to be Used for Science Testing | Generated Full suite of LST products globally for two 16-day periods with start date of 2003001 and 2003193. |
| Justification | The operational C6 products from the earlier version of the PGE were not usable for any science or validation purposes since large temperature/emissivity errors present in the product for atmospheric conditions exceeding 2 cm of water vapor and uncertainties will increase whenever MERRA2 atmospheric data have large uncertainty. This software update fixes this issue in addition to other known issues in the operational product. Accuracy of retrieved LST is verified to be within 1 K |
| Effective Date for Implementation of Change | Products to be reprocessed from the beginning of the mission of Terra and Aqua |
| Status | Major algorithm development completed. Michael D. King approved 9/12/18. Sadashiva Devadiga approved 09/12/2018. Gang Ye approved on 09/12/2018. |
