MODAPS PCR 14-004
| PCR Number | 14-004 |
|---|---|
| Date | 2014-01-08 |
| Initiator | Bill Ridgway |
| Abstract | To implement major updates in PGE06 v6.0.73. |
| Problem Statement | Major updates were implemented as described below. Additionally, a pre-processed MYD021KM file is used to implement Band 1 & 2 registration fix with updated 250m to 1km aggregations (Wolfe Kernel). |
| Description of Change | The cloud products include cloud-top and optical/microphysical properties. The cloud-top property product changes include new 1 km SDSs in addition to the legacy 5 km SDSs, and a new physical cloud height dataset.Cloud optical/microphysical product changes include expanded/improved pixel-level retrieval uncertainty calculations that are intended to be used in lieu of retrieval QA assignments that are no longer assigned (legacy QA bits are now set to a value of 3 for all successful retrievals). Retrievals are now attempted on a pixel flagged as likely to have a partly cloudy field of view by the so-called clear sky restoral algorithm introduced in C5 processing. Successful retrievals from this pixel population have similar SDS names as the non-flagged pixel population but with “_PCL” (for Partly CLoudy) appended to the end of the parameter name; an exception is the uncertainty SDSs where both PCL and non-PCL retrieval uncertainties are kept. Metrics for unsuccessful retrievals (those outside the look-up table solution space) are now provided as well (Retrieval_Failure_Metric_*). Finally, absolute retrievals are provided for the other visible and near-infrared (VNIR) and shortwave infrared band pairs (VNIR and 1.6 µm, VNIR and 3.7 µm) instead of as differences relative to the VNIR/2.1 µm retrieval. Other dataset changes are detailed in the document link given above.It was found during C6 development that cloud optical property retrievals were sensitive to an improved 1 km L1B aggregation of the Aqua MODIS bands 1 (0.66 µm) and 2 (0.86 µm) native 250 m reflectances that partially accounts for misregistration of the VNIR focal plane with the other three focal planes. This intermediate L1B file (not archived but to be made available on demand) is used for all atmosphere team processing but was found to only affect optical property L3 retrieval statistics.Algorithm refinement for the Cirrus_Reflectance dataset is no longer being supported by NASA. Before support was terminated, updates to the C6 algorithm included use of the de-striped L1B reflectance data file that was developed for clear and cloudy-sky infrared algorithms but also includes band 26 (1.38 µm) used by the cirrus reflectance algorithm. |
| Products Affected | MYD06_L2 |
| Software Affected | PGE06 v6.0.73[AP]M1M_C6_A1m 6.0.122 |
| Processing String to Receive the Change | Aqua Forward, Aqua Reprocessing |
| Downstream Product Effects | Subset products (PGE83), Browse products (PGE89, PGE108) and Level 3 MYD08_*3 products. |
| Data Granules to be Used for Science Testing | A long series of science tests were required to develop the new algorithm. Tests are documented on the team site at http://modis-atmos.gsfc.nasa.gov/team/pge06_test_details.html.2010-059 |
| Justification | Improved Cloud Top properties and Cloud Optical properties. |
| Effective Date for Implementation of Change | Jan 1, 2014 for Aqua forward reprocessing. Reprocessing for the full Aqua mission. |
| Status | Major algorithm development and testing completed. Steve Platnick approved on 1/8/2014. Michael King approved on 2/7/2014. |
