MODAPS PCR 11-041
| PCR Number | 11-041 |
|---|---|
| Date | 2011-09-07 |
| Initiator | James Kuyper |
| Abstract | This Aqua LUT patch PGE02 5.0.41_1 (recipes PM1M_1(nrt)m(c) 3.3.99) includes a new algorithm to calculate the default b1 on-orbit considering the impact of the real time LWIR FPA temperature. |
| Problem Statement | The current Aqua L1B code uses fixed b1 values for bands 33, 35 and 36 when the blackbody temperature is above a certain threshold. LWIR FPA temperature variations have recently increased due to the loss of radiative cooler margin. This is only a problem during warm-up/cool-down calibration tests, which last about 4 hours and happen only once every 3 months. |
| Description of Change | An algorithm to calculate temperature-dependent b1 values was developed by MCST. The new default b1 is calculated as:b1 = default_b1_baseline*(1+c1*(Tlwir – Tlwir_baseline))Where default_b1_baseline, c1 and Tlwir_baseline are provided by MCST through 3 new time-dependent LUTs, Tlwir is the real time LWIR FPA temperature. One old lut bb_t_sat_default_b1_aqua_table is removed. |
| Products Affected | MYD021KM (recipes PM1M_1(nrt)m(c) 3.3.99) |
| Software Affected | PGE02 v5.0.41 |
| Processing String to Receive the Change | Aqua Forward |
| Downstream Product Effects | Any downstream product using Aqua bands 33, 35 and 36 L1B data may be affected. The impact only occurs during blackbody warm up/cool down events, and should be about 1%. |
| Data Granules to be Used for Science Testing | Aqua granules between 2011233.0840 and 2011233.1315.2010-059 |
| Justification | The internal tests requested by MCST have demonstrated that the new algorithm accurately adjusts for the impact of the LWIR FPA temperature changes. |
| Effective Date for Implementation of Change | 2012-04-15 |
| Status | Bill Ridgway and Chris Moeller approved for Atmospheres, Robert Wolfe approved for Land, Michael King approved on 04/06/2012. |
