MODAPS PCR 06-009
| PCR Number | 06-009 |
|---|---|
| Date | 2006-07-10 |
| Initiator | Suzanne Wetzel Seemann |
| Abstract | New regression data are applied to reduce the dry bias in Terra profiles for moist cases over land scenes. |
| Problem Statement | Like Aqua, but less dramatic, the MODIS Terra Profiles exhibit a dry bias formoist cases when compared to measurements of the Southern Great PlainsAtmospheric Radiation Measurement site. Globally, MODIS is more moist thanSSMI for the very wet cases over the ocean which may indicate that the problem is limited to land scenes. |
| Description of Change | Regression coefficients are computed from an updated set of training dataprofiles. There are now 15704 profiles (was 12245). The increase comes from adding new ozonesondes and increasing the saturation threshold to 99%. New emissivity derived from the UW-Madison global gridded IR emissivity dataset is assigned to the Profiles. Emissivity is included at eight inflection point wavelengths, [3.7, 4.3, 4.5, 7.6, 8.3, 9.3, 10.8, 14.3]. New forward model pCRTM is used to compute synthetic radiances instead ofthe old PFAAST. |
| Products Affected | MOD07_L2 |
| Software Affected | PGE03 |
| Processing String to Receive the Change | Terra Forward, Terra Reprocessing |
| Downstream Product Effects | Temperature and Moisture Profiles from MOD07_L2 are used as input to Land PGE16 surface temperature retrieval. A copy of the MOD07_L2 Water_Vapor (IR retrieval) is written into the Atmosphere L2 MOD05_L2 Water Vapor product and also into the MODATML2 Joint Level product. MOD07_L2 parameters flow into Atmosphere L3 processing chain, including Water Vapor (High, Low and Total), Total Ozone, Lifted Index, and Total Totals. |
| Data Granules to be Used for Science Testing | Separate discipline tests were conducted by the Atmosphere and Land teams. Atmosphere uses a standard test suite of 19 Terra data days that span the months and seasons, contain a 5-day aerosol outbreak event, and permit basic testing of the L3 products. The Land team Profile test was directed at PGE16. The results of this test are acceptable to the PGE16 Principal Investigator. |
| Justification | An improved Profiles product with more accurate Total Precipitable Waterand Ozone data are available. |
| Effective Date for Implementation of Change | Start of C5 Terra Reprocessing. |
| Status | PI approved. Nazmi Saleous approved for Land, Michael King approved for Atmosphere, Vincent Salomonsom approved. |
