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MOD06_L2
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Format & Content

File Format Basics

MOD06_L2 product files are stored in Hierarchical Data Format (HDF). HDF is a multi-object file format for sharing scientific data in multi-platform distributed environments. HDF files should only be accessed through HDF library subroutine and function calls, which can be downloaded from the HDF web site. Forty-four of the forty-six gridded parameters listed below are stored as Scientific Data Sets (SDS's) within the HDF file, the remaining two (Band_Number and Statistics_1km) are stored as VData (table arrays).

Individual parameters are stored at either 1 kilometer or 5 kilometer pixel resolution (details are given below).




Collection 6
(primary SDS's only, not a complete list)


MOD06_L2 Dimension List  

  1. Cell_Along_Swath_5km = 406
  2. Cell_Across_Swath_5km = 270
  3. Cell_Along_Swath_1km = 2030
  4. Cell_Across_Swath_1km = 1354
  5. Band_Number = 7
  6. Band_Ratio = 5
  7. Band_Forcing = 5
  8. Band_Difference = 2
  9. Radius_Difference = 2
  10. QA_Parameter_5km = 10
  11. QA_Parameter_1km = 5
  12. Cloud_Mask_1km_Num_Bytes = 2
  13. Number_of_Instrument_Scans = 203 (typical)
  14. Maximum_Number_of_1km_Frames = 1354 (typical)



MOD06_L2 Scientific Data Sets (SDS's)
(Primary SDS's only, not a complete list)

    Geolocation and Time Parameters

  1. Longitude
      Description: Geodetic Longitude
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -180 to +180 degrees east
  2. Latitude
      Description: Geodetic Latitude
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -90 to +90 degrees north
  3. Scan_Start_Time
      Description: International Atomic Time at Start of Scan replicated across the Swath
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 0.0 to 3.1558E+9 seconds since 1 January 1993 00:00:00

    Solar and Viewing Geometry Parameters

  4. Solar_Zenith
      Description: Solar Zenith Angle, Cell to Sun
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 0 to +180 degrees
  5. Solar_Azimuth
      Description: Solar Azimuth Angle, Cell to Sun
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -180 to +180 degrees
  6. Sensor_Zenith
      Description: Sensor Zenith Angle, Cell to Sensor
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 0 to 180 degrees
  7. Sensor_Azimuth
      Description: Sensor Azimuth Angle, Cell to Sensor
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -180 to 180 degrees

    Science Parameters

      Cloud Top Parameters (5km)

    Note that seperate Near Nadir (SZA LE 32) Retrievals are stored in (similar/parallel) SDS's with the string "Nadir" in the SDS name. These generally are more reliable than regular retrievals, since they only contain ONLY data that was retrieved with a less oblique instrument scanner view.

  8. Brightness_Temperature
      Description: Brightness Temperature for MODIS Bands 29, 31, 32, 33, 34, 35, and 36
      Dimensions: (Band_Number ,Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 150 to 350 K
  9. Surface_Temperature
      Description: Surface Temperature
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 150 to 350 K
  10. Surface_Pressure
      Description: Surface Pressure
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 800 to 1100 hPa
  11. Processing_Flag
      Description: Cloud Retrieval Method Flag
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  12. Cloud_Height_Method
      Description: Cloud Height Method
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array, with values from 1 to 6)
      Detail: The cloud height method index indicates if a CO2-slicing retrieval or window channel retrieval was output.
      Further, if a CO2-slicing retrieval was output, it specifies the MODIS band pair used to generate the result.
      The index ranges from 1 to 6, defined as follows: 1 = Bands 36/35, 2 = Bands 35/34, 3 = Bands 35/33,
      4 = Bands 34/33, 5 = Bands 33/31 (not used), 6 = Window channel method.
  13. Cloud_Top_Pressure
      Description: Cloud Top Pressure
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  14. Cloud_Top_Pressure_Day
      Description: Cloud Top Pressure for daytime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  15. Cloud_Top_Pressure_Night
      Description: Cloud Top Pressure for nighttime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  16. Cloud_Top_Temperature
      Description: Cloud Top Temperature
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      valid_range: 150 to 350 K
  17. Cloud_Top_Temperature_Day
      Description: Cloud Top Temperature for daytime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      valid_range: 150 to 350 K
  18. Cloud_Top_Temperature_Night
      Description: Cloud Top Temperature for nighttime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      valid_range: 150 to 350 K
  19. Tropopause_Height
      Description: Tropopause Height
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  20. Cloud_Fraction
      Description: Cloud Fraction
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  21. Cloud_Fraction_Day
      Description: Cloud Fraction for daytime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  22. Cloud_Fraction_Night
      Description: Cloud Fraction for nighttime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  23. Cloud_Effective_Emissivity
      Description: Cloud Effective Emissivity
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  24. Cloud_Effective_Emissivity_Day
      Description: Cloud Effective Emissivity for daytime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  25. Cloud_Effective_Emissivity_Night
      Description: Cloud Effective Emissivity for nighttime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  26. Cloud_Top_Pressure_Infrared
      Description: Cloud Top Pressure from IR Window
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  27. Spectral_Cloud_Forcing
      Description: Spectral Cloud Forcing
      Dimensions: (Band_Forcing, Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -20 to 20 watts/meter2/steradian/Ám
  28. Cloud_Top_Pressure_From_Ratios
      Description: Cloud top pressure from ratios (36/35, 35/34, 35/33, 34/33, 33/31)
      Dimensions: (Band_Ratio, Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 1 to 1100 hPa
  29. Surface_Type
      Description: Surface Type based on Emissivity
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 0 to 200
  30. Radiance_Variance
      Description: Radiance Variance for MODIS Bands 29, 31, 32, 33, 34, 35, and 36
      Dimensions: (Band_Number, Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: 0.00 to 0.20 watts/meter2/steradian/Ám
  31. Brightness_Temperature_Difference
      Description: Brightness Temperature Difference (Bands 29-31 & 31-32)
      Dimensions: (Band_Difference, Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: -20 to 300 K
  32. Cloud_Phase_Infrared
      Description: Cloud Phase Infrared
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array) clear = 0; liquid water = 1; ice = 2 ; mixed = 3; uncertain = 6
  33. Cloud_Phase_Infrared_Day
      Description: Cloud Phase Infrared for daytime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array) clear = 0; liquid water = 1; ice = 2 ; mixed = 3; uncertain = 6
  34. Cloud_Phase_Infrared_Night
      Description: Cloud Phase Infrared for nighttime scenes
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array) clear = 0; liquid water = 1; ice = 2 ; mixed = 3; uncertain = 6
  35. Cloud_Mask_5km
      Description: MODIS cloud mask, first byte
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km)
      Valid Range: (byte array)
  36. Quality_Assurance_5km
      Description: Quality Assurance at 5x5 km resolution
      Dimensions: (Cell_Along_Swath_5km, Cell_Across_Swath_5km, QA_Parameter_5km)
      Valid Range: (byte array)
  37. Band_Number
      Description: MODIS Band Number
      Dimensions: (Band_Number)
      Valid Range: (vdata table array)

      Cloud Optical Parameters (1km)

    Note that seperate Partly Cloudy Retrievals are stored in (similar/parallel) SDS's with the string "_PCL" in the SDS name. These generally have higher uncertainties than regular cloudy scene retrievals, and data users should use a bit more caution and care with these PCL retrievals.

  38. Cloud_Optical_Thickness
      Description: Cloud Optical Thickness
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  39. Cloud_Optical_Thickness_Uncertainty
      Description: Cloud Optical Thickness Relative Uncertainty (Percent)
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 200%
  40. Cloud_Effective_Radius
      Description: Cloud Effective Particle Radius
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  41. Cloud_Effective_Radius_Uncertainty
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent)
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 200%
  42. Effective_Radius_Difference
      Description: Cloud Particle Effective Radius two-channel retrieval using band 6 and band 20 differenced from band 7 retrieval and either band 1, 2, or 5 (specified in Quality_Assurance_1km). Dimension 1 of SDS is band 6 - band 7 retrieval, Dimension 2 is band 20 - band 7 retrieval
      Dimensions: (Radius_Difference, Cell_Along_Swath_1km, Cell_Across_Swath_1km, Radius_Difference)
      Valid Range: -90 to 90 µm
  43. Cloud_Water_Path
      Description: Column Water Path two-band retrieval using band 7 and either band 1, 2, or 5 (specified in Quality_Assurance_1km)
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2
  44. Cloud_Water_Path_Uncertainty
      Description: Column Water Path Relative Uncertainty (Percent)
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2


  45. Cloud_Phase_Optical_Properties
      Description: Cloud Phase Determination Used in Optical Thickness/Effective Radius Retrieval
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 4 (0=fill, 1=clear, 2=liquid water cloud, 3=ice cloud, 4=undetermined phase cloud)
  46. Cloud_Multi_Layer_Flag
      Description: Cloud Multi Layer Identification From MODIS Shortwave Observations
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 8 (0=fill, 1=single layer, 2 through 8=increasing confidence of multilayer clouds)


  47. Cloud_Optical_Thickness_1621
      Description: Cloud Optical Thickness two-channel retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  48. Cloud_Optical_Thickness_Uncertainty_1621
      Description: Cloud Optical Thickness Relative Uncertainty (Percent) two-channel retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  49. Cloud_Effective_Radius_1621
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  50. Cloud_Effective_Radius_Uncertainty_1621
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  51. Cloud_Water_Path_1621
      Description: Column Water Path two-band retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2
  52. Cloud_Water_Path_Uncertainty_1621
      Description: Column Water Path Relative Uncertainty (Percent) two-band retrieval using band 6 and band 7
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2


  53. Cloud_Optical_Thickness_16
      Description: Cloud Optical Thickness two-channel retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  54. Cloud_Optical_Thickness_Uncertainty_16
      Description: Cloud Optical Thickness Relative Uncertainty (Percent) two-channel retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  55. Cloud_Effective_Radius_16
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  56. Cloud_Effective_Radius_Uncertainty_16
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  57. Cloud_Water_Path_16
      Description: Column Water Path two-band retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2
  58. Cloud_Water_Path_Uncertainty_16
      Description: Column Water Path Relative Uncertainty (Percent) two-band retrieval using band 6 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2


  59. Cloud_Optical_Thickness_37
      Description: Cloud Optical Thickness two-channel retrieval using using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  60. Cloud_Optical_Thickness_Uncertainty_37
      Description: Cloud Optical Thickness Relative Uncertainty (Percent) two-channel retrieval using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 100
  61. Cloud_Effective_Radius_37
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  62. Cloud_Effective_Radius_Uncertainty_37
      Description: Cloud Effective Particle Radius Relative Uncertainty (Percent) two-channel retrieval using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 90 µm
  63. Cloud_Water_Path_37
      Description: Column Water Path two-band retrieval using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2
  64. Cloud_Water_Path_Uncertainty_37
      Description: Column Water Path Relative Uncertainty (Percent) two-band retrieval using band 20 and either band 1, 2, or 5
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 9000 g/m^2


  65. Cloud_Mask_1km
      Description: MODIS Cloud Mask, first byte
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: (byte array)
      Detail: (See QA Plan for detail)
  66. Quality_Assurance_1km
      Description: QA Flags at 1x1 km resolution
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km, QA_Parameter_1km)
      Valid Range: (byte array)
      Detail: (See QA Plan for detail)

      Cirrus Detection Parameters (1km)

  67. Cirrus_Reflectance
      Description: Cirrus Reflectance
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: 0 to 1
  68. Cirrus_Reflectance_Flag
      Description: Cirrus Reflectance Flag
      Dimensions: (Cell_Along_Swath_1km, Cell_Across_Swath_1km)
      Valid Range: (byte array)