XAERDT_L2_AHI_H08 - AHI/Himawari-08 Dark Target Aerosol 10-Min L2 Full Disk 10 km

The Geostationary Earth Orbit (GEO)-Low-Earth Orbit (LEO) Dark Target Aerosol project under NASA's Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, led by Robert Levy, uses a special version of the MODIS Dark Target (DT) aerosol retrieval algorithm to produce Aerosol Optical Depth (AOD) and other aerosol parameters derived independently from eight sensor/platform combinations, where four are in GEO and four are in LEO. The four GEO sensors include Advanced Baseline Imagers (ABI) on both GOES-16 (GOES-East) and GOES-17 (GOES-West), and Advanced Himawari Imager (AHI) on Himawari-8 and Himawari-9. The four LEO sensors include MODIS on both Terra and Aqua, and VIIRS on both Suomi-NPP and NOAA-20. Adding the LEO sensors reinforces a major goal of this project, which is to render a consistent science maturity level across DT aerosol products derived from both types and sources of orbital satellites.

Within this Level-2 (L2) product suite, the DT algorithm is applied over land and ocean separately, which produces AOD and other aerosol parameters over land only, over ocean only, and a combined subset. Users may assess each retrieved land or ocean aerosol value in these L2 products based on their quality flag (Land_Ocean_Quality_Flag) and confidence levels based on their error flag (Error_Flag_Land_And_Ocean). This project has made a concerted effort to ensure that products within both the GEO and LEO groups are structurally consistent in their data and metadata elements as much as possible.

The Himawari-8 platform served in the operational Himawari position (near 140.7°E) between October 2014 and 13 December 2022. Himawari-9 replaced Himawari-8 and is currently operational. The Himawari/AHI L2 Dark Target Aerosol product, in netCDF4 format, is provided at 10-km spatial resolution (at-nadir) and a 10-minute full-disk cadence that typically yields about 142 granules over the daylit hours of a 24-hour period (there are no images produced at 02:20 or 14:20 UTC for navigation purposes). These GEO observations are regional but provide daytime time dependence. The Himawari-8/AHI collection record spans from January 2019 through 12 December 2022. The final 19 days of 2022 (December 13 through 31) are served by L2 products derived from the Himawari-9/AHI instrument.

The L2 netCDF product contains the following 45 Science Data Set (SDS) layers that include eight geolocation and 37 geophysical SDSs:

Geolocation_Data

1. longitude
2. latitude
3. solar_zenith_angle
4. solar_azimuth_angle
5. sensor_zenith_angle
6. sensor_azimuth_angle
7. Scattering_Angle
8. Glint_Angle

Geophysical_Data

1. Aerosol_Cldmask_Land_Ocean
2. Aerosol_Cloud_Fraction_Land
3. Aerosol_Cloud_Fraction_Ocean
4. Aerosol_Type_Land
5. Angstrom_Exponent_1_Ocean
6. Angstrom_Exponent_2_Ocean
7. Asymmetry_Factor_Average_Ocean
8. Average_Cloud_Pixel_Distance_Land_Ocean
9. Backscattering_Ratio_Average_Ocean
10. Cloud_Pixel_Distance_Land_Ocean
11. Corrected_Optical_Depth_Land
12. Effective_Optical_Depth_Average_Ocean
13. Effective_Radius_Ocean
14. Error_Flag_Land_And_Ocean
15. Fitting_Error_Land
16. Image_Optical_Depth_Land_And_Ocean
17. Land_Ocean_Quality_Flag
18. Land_Sea_Flag
19. Least_Squares_Error_Ocean
20. Mass_Concentration_Land
21. Mass_Concentration_Ocean
22. Mean_Reflectance_Land
23. Mean_Reflectance_Ocean
24. Number_Pixels_Used_Land
25. Number_Pixels_Used_Ocean
26. Optical_Depth_By_Models_Ocean
27. Optical_Depth_Land_And_Ocean
28. Optical_Depth_Large_Average_Ocean
29. Optical_Depth_Ratio_Small_Land
30. Optical_Depth_Ratio_Small_Ocean_0p55micron
31. Optical_Depth_Small_Average_Ocean
32. PSML003_Ocean
33. STD_Reflectance_Land
34. STD_Reflectance_Ocean
35. Surface_Reflectance_Land
36. Topographic_Altitude_Land
37. Wind_Speed_GMAO_Ocean