Production | MODAPS Services

MODAPS PCR 22-004

PCR Number	22-004
Date	2022-06-10
Initiator	Sudipta Sarkar on behalf of P.I. Alexei Lyapustin
Abstract	PGE165 6.1.0, PGE113 6.1.19 Only major changes have been shown here for brevity: 1. Changed the SDS "AOD_model" in MCD19A2 file to "AngstromExp_470-870" 2. Changed the datatype of SDS "FineModeFraction" to float numbers 3. Added three SDS ("NBAR_250m", "NDVI1km", "NDVI_NBAR_UpdateDay") into MCD19A3 file 4. Added one more type of ancillary file (EM_LC_Latlon), added one more LUN to read these files 5. Change snow product from orbit base to daily 6. Updated science code for AOD and snow retrievals 7. Added one more SDS to output Snow fraction and Snow grain size update day 8. Adjusted AOD model file 9. Updated Look-up table 10. Ancillary files AOD_model are updated 11. Replaced 8day MCD19A3 to daily MCD19A3D 12. Read additional LUT when run over AOD model transition zone. 13. Increased the SZA range 14. Move four SDSs ("Snow_Fraction", "Snow_Grain_Size", "Snow_Fit", "Snow_UpdateDay" ) from MCD19A1 to MCD19A3 product
Problem Statement	Generate the C61 MAIAC suite of tiled products, MCD19A1/A2/A3D as part of Collection 6.1 (C6.1) re-processing using science team recommended changes to the science processing algorithm.
Description of Change	Key changes in the data: 1. Following products were added in C61: - AngstromExp_470-780 (Angstrom exponent) - NBAR_250m (gap filled 250m NBAR for Red and NIR bands) NDVI1km(1km gap filled NDVI) 2. Following products are removed: AOD_MODEL Sur_albedo 3. Snow products were changed from orbit level to daily gap-filled products: Snow_Fraction, Snow_Grain_Size, Snow_Fit. 4. BRDF will be now reported daily (MCD19A3 now reported as MCD19A3D) C61 Specific Algorithm Change/Improvements: 1. Improved aerosol model for more accurate AOD retrieval for smoke and dust. 2. Improved the overall performance (AOD, FMF, water-leaving reflectance) over the coastal and remote ocean, including sediment-rich waters with high Red-NIR reflectance. 3. Increased maximum AOD at 0.47�m to 6 (from 4 in C6). 4. Introduced GDAS temperature profiles to derive Plum Injection Height. 5. Due to calibration uncertainties in B8, the reported B8 BRDF is now obtained from the Blue band (B3) by scaling. 6. The RTLS BRDF model was modified in MAIAC C6.1 to accommodate higher range of solar and view zenith angles (where standard RTLS model is unstable) 7. MAIAC specific polarization correction update and improvements to MODIS Terra L1B high latitude striping were incorporated through creation of MAIAC specific L1B gridding process (PGE165).
Products Affected	Daily C61 L3 Tiled MAIAC products, MCD19A1, MCD19A2, and MCD19A3D
Software Affected	PGE165 V6.1.0, PGE113 6.1.19
Processing String to Receive the Change	Terra and Aqua Forward Processing. Terra and Aqua Reprocessing. NRT
Downstream Product Effects	None
Data Granules to be Used for Science Testing	A series of science tests have been carried out to assess and fully confirm all production rule and science changes, in AS 1850, AS 1884, AS 1899 and others. The outputs from this test were fully assessed and approved by LDOPE and the science team.
Justification	The C61 products carry a number of critical science improvements and also carry some changes in data format and added datasets that were requested by the user community.
Effective Date for Implementation of Change	MODAPS was requested to start the reprocessing of the C61 MAIAC products, with all the changes mentioned herein, as of 06/02/2022. The products, whatever have been generated this far, have been reviewed by LDOPE and science team and approved for release from the DAACs.
Status	Major algorithm development completed. Sadashiva Devadiga approved on 06/29/2022. Sudipta Sarkar approved on 06/29/2022.