MODAPS PCR 18-001
| PCR Number | 18-001 |
|---|---|
| Date | 2018-07-30 |
| Initiator | Lin, Guoqing (Gary) |
| Abstract | PGE01 v6.0.27. Updated Long Term Trend in Geolocation LUTs for Terra and Aqua through 2020-06-04. PGE01 v6.1.4. Corrected Long Term Trend in Geolocation LUTs. |
| Problem Statement | The MODIS instruments on the Terra and Aqua satellites have systematic long-term variations in it’s orientation relative to the rest of the satellite. A significant part of the total variation is an annual variation that is believed to be due to thermal strains due to seasonal variation in the average amount of sunlight, but there’s more to it than that. A look-up table is used to apply time-dependent adjustments to the instrument orientation. In versions 6.0.26 and 6.1.3, those tables extend only up to 2018-08-06, and the adjustment will become increasingly inaccurate after that date. |
| Description of Change | Extend the long-term-trend tables to include predicted values through 2020-06-04. |
| Products Affected | M[OY]01, M[OY]03 |
| Software Affected | PGE01 v6.0.27 PGE01 v6.1.4 |
| Processing String to Receive the Change | Terra and Aqua Forward Processing, Terra and Aqua Reprocessing, NRT |
| Downstream Product Effects | Decreased accuracy of Geolocation will be avoided. |
| Data Granules to be Used for Science Testing | 16-day test of C6 Terra and Aqua PGEs up to daily LSR, CMG LSR and 16-day LSR in AS1632. 16-day test of C6.1 Terra and Aqua PGEs up to daily LSR, CMG LSR and 16-day LSR in AS1633. |
| Justification | The expected variation in the instrument orientation needs to be corrected to get acceptable geolocation accuracy. |
| Effective Date for Implementation of Change | From 2018-08-05 or ASAP. |
| Status | Major algorithm development completed. Guoqing (Gary) Lin approved 07/30/2018; Robert Wolfe approved 07/30/2018; Gang Ye approved on 07/30/2018. |
