MODAPS PCR 2005-10-11
| PCR Number | |
|---|---|
| Date | 2005-10-11 |
| Initiator | Richard Frey |
| Abstract | Add bias corrections to cloud top retrieval algorithm (CO2-slicing). |
| Problem Statement | The MOD06CT algorithm (CO2-slicing) uses calculated clear-sky radiances in the computation of cloud top pressures (CTPs). There are systematic errors in these calculations that may be mitigated by application of bias correction factors in the MODIS bands used (33-36). Until recently, it has not been clear how to compute and apply these factors such that an improvement in CTPs is realized. We are submitting code to both create and apply these bias corrections. |
| Description of Change | MOD06CT will read in 1-degree zonal clear-sky bias (mean observed minus calculated) values computed over 8 days for each of bands 33-36. These biases will be added to the clear-sky calculation used in each cloud top pressure retrieval. Clear pixels are determined by 1-km MOD35 output. In addition, a constant representing instrument or measurement bias in each of bands 33-36 will be added. These values are taken from AIRS vs. MODIS radiance measurements as reported by Tobin, et al., in press). |
| Products Affected | MYD06_L2 |
| Software Affected | PGE06 |
| Processing String to Receive the Change | Aqua Forward, Aqua Reprocessing |
| Downstream Product Effects | All products using cloud top pressure, cloud top temperature, or effective cloud amount as input. |
| Data Granules to be Used for Science Testing | Several global days. |
| Justification | See attached document. |
| Effective Date for Implementation of Change | Start of C5 Aqua Reprocessing. |
| Status |
