::: Himawari-9 AHI Validation Web :::


Product:
  Aerosol Property - Aerosol Optical Thickness (ARP-AOT)
  - L2 (Ver. 3.1) 
  - L3 hourly (Ver. 3.1)
      5km spatial resolution

Validation data:
  Terra and Aqua MODIS aerosol product (MOD04,MYD04 L2)
      10km spatial resolution

  - Land: AOT at 0.5 micron interpolated from AOTs at 0.47 micron and 0.55 micron of
    "15. Corrected_Optical_Depth_Land" by logarithminc interpolation
  - Sea: AOT at 0.5 micron interpolated from AOTs at 0.47 micron and 0.55
    micron of "35. Effective_Optical_Depth_Best_Ocean" by logarithminc interpolation

Comparison conditions:
  - Temporal Condition: The latest Himawari-9 AOT data within +/- 5 min from
    the observation time of MODIS.
  - Spatial Condition: The average of the nearest 4 pixels of Himawari-9 AOT
    data to the center of a pixel of MODIS data

Data screening:
  - Cloud flag of Himawari-9 AOT = clear,  additional cloud test = clear
    (QA_flag bit8 = 0)
  - Himawari-9 AOT is valid (AOT != -32768.0)
  - AOT ranging from 0 to 2 for both Himawari-9 and MODIS

Definition:
  - Bias = Himawari-9 AOT - MODIS AOT

The graphs shown:

  (a) Monthly scatter plot

  (b) Monthly scatter plot (confidence = very good or good)

  (c) Bias and RMSE assuming Aqua/MODIS AOT as a basis

  (d) Bias and RMSE assuming Terra/MODIS AOT as a basis

  (e) Bias and RMSE assuming Terra and Aqua MODIS AOT as bases