MODAPS PCR 14-014
| PCR Number | 14-014 |
|---|---|
| Date | 2014-07-25 |
| Initiator | Brian Wenny |
| Abstract | To implement updates in (Terra) PGE02 V6.1.16 and (Aqua) PGE02 V6.1.31 for Collection 6 Terra Band 5 calibration. |
| Problem Statement | PGE02 Code change is requested by SDST for the SDP toolkit update (5.2.17). This change does not have any impact to L1B data.However, MCST observed systematic upward drift in trending of the Terra band 5 TOA reflectance for all desert targets used for the calibration monitoring of MODIS, increasing reflectance about 1.5% over the mission period. MCST delivered a new LUT to fix this for the entire mission period with needed correction applied in the forward processing. This fix to correct for the observed trending in band 5 will also result in changes to reflectance in band 26 since a SWIR band crosstalk related correction in L1B uses band 5 to correct band 26. |
| Description of Change | Update the PGE02 version number from 6.1.14 to 6.1.16 for Terra MODIS and the version number from 6.1.17 to 6.1.31 for Aqua MODIS.A LUT change is introduced in the Terra MODIS L1B to correct a long-term drift in the reflectance trending for band 5 and 26, which requires a reprocessing for C6 Terra L1B. |
| Products Affected | C6 PGE02 version number changed.C6 Terra MODIS L1B product updated in Band 5 and 26. |
| Software Affected | PGE02 V6.1.16 & PGE02 V6.1.31 |
| Processing String to Receive the Change | Terra Forward, Terra Reprocessing, Aqua Forward |
| Downstream Product Effects | All C6 Terra products. No change for Aqua. |
| Data Granules to be Used for Science Testing | Data Granules to be used for Science Testing: AS 1175, AS 1180, and AS1181. |
| Justification | MCST has delivered Band 5 and 26 correction tools to SDST to reprocess C6 Terra L1B data. All changes are expected.MODAPS will start reprocessing the C6 Terra L1B using the MCST provided tool on about July 28, 2014. This reprocessing is expected to complete by Aug 15, 2014. The C6 L1B product currently available in the LAADS archive will be removed and replaced with the products from this reprocessing. Change in TOA reflectance in band 5 from this LUT update is not significant and will have little or no effect on downstream products.During this reprocessing users will not be able to search or order the Terra C6 L1B products from the LAADS archive. Once the reprocessing is complete products from the entire mission period will be released. Users who have already downloaded the data from the on-going reprocessing, if needed, can either download the newly reprocessed data from LAADS, or can use a tool to correct the band 5 in the earlier version of the C6 L1B using a tool that will be made available upon request. |
| Effective Date for Implementation of Change | Two weeks to reprocess Terra C6 L1B data. |
| Status | X. Xiong and S. Platnick approved. Michael King approved on 7/25/2014. |
