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File Format Basics
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MOD07_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.
Each of the 12 gridded parameters listed below
is stored as a Scientific Data Set (SDS) within the HDF file.
All SDS's are stored at 5-kilometer pixel resolution.
The Cloud Mask SDS, derived from the 1-km MOD35_L2 Cloud Mask parameter,
is remapped to 5-km resolution, by using only the center 1-km pixel
in the 5x5 pixel retreival array.
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MOD07_L2 Dimension List
- Cell_Along_Swath = 406 (typical)
- Cell_Across_Swath = 270 (typical)
- Band_Number = 15
- Pressure_Level = 20
- Output_Parameter = 10
- Water_Vapor_QA_Bytes = 5
MOD07_L2 Scientific Data Set (SDS) List
Geolocation and Time Parameters
- Latitude
Description: Geodetic Latitude
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -90 to +90 degrees north
- Longitude
Description: Geodetic Longitude
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -180 to +180 degrees east
- Scan_Start_Time
Description: International Atomic Time at Start of Scan
replicated across the Swath
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0.0 to 3.1558E+9 seconds since 1 January 1993 00:00:00
Solar and Viewing Geometry Parameters
- Solar_Zenith
Description: Solar Zenith Angle, Cell to Sun
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to +180 degrees
- Solar_Azimuth
Description: Solar Azimuth Angle, Cell to Sun
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -180 to +180 degrees
- Sensor_Zenith
Description: Sensor Zenith Angle, Cell to Sensor
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 180 degrees
- Sensor_Azimuth
Description: Sensor Azimuth Angle, Cell to Sensor
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -180 to 180 degrees
Science Parameters
- Brightness_Temperature
Description: Brightness Temperature
Dimensions: (Band_Number, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Surface_Temperature
Description: Surface_Temperature
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Surface_Pressure
Description: Surface_Pressure
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 800 to 1100 hPa
- Surface_Elevation
Description: Surface_Elevation
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -400 to 8840 meters
- Processing_Flag
Description: Processing_Flag
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: byte array
- Tropopause_Height
Description: Tropopause_Height
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 1 to 1100 hPa
- Guess_Temperature_Profile
Description: Guess_Temperature_Profile
Dimensions: (Pressure_Level, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Guess_Moisture_Profile
Description: Guess Dew Point Temperature Profile
Dimensions: (Pressure_Level, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Retrieved_Temperature_Profile
Description: Retrieved Temperature Profile
Dimensions: (Pressure_Level, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Retrieved_Moisture_Profile
Description: Retrieved Dew Point Temperature Profile
Dimensions: (Pressure_Level, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 150 to 350 K
- Retrieved_Height_Profile
Description: Retrieved Geopotential Height Profile
Dimensions: (Pressure_Level, Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 65000 meters
- Total_Ozone
Description: Total Ozone Burden
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 500 Dobson units
- Total_Totals
Description: Total Totals
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 80 K
- Lifted_Index
Description: Lifted Index
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -20 to 40 K
- K_Index
Description: K Index
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: -5 to 65 K
- Water_Vapor
Description: Total Column Precipitable Water Vapor - IR Retrieval
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 20 cm
- Water_Vapor_Low
Description: Precipitable Water Vapor Low - IR Retrieval
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 20 cm
- Water_Vapor_High
Description: Precipitable Water Vapor High - IR Retrieval
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: 0 to 20 cm
Quality Assurance
- Quality_Assurance
Description: Quality Assurance Parameters
Dimensions: (Cell_Along_Swath, Cell_Across_Swath, Output_Parameter)
Valid Range: bit field
- Quality_Assurance_Infrared
Description: Runtime Quality Assurance Flags for Water_Vapor_Infrared
Dimensions: (Cell_Along_Swath, Cell_Across_Swath, Water_Vapor_QA_Bytes)
Valid Range: bit field
Cloud Mask
- Cloud_Mask
Description: MODIS Cloud Mask , First Byte
Dimensions: (Cell_Along_Swath, Cell_Across_Swath)
Valid Range: bit field
MOD07_L2 VData (Tables) List
- Band_Number
Description: MODIS Band Number
Dimensions: (Band_Number)
Data Values: 20, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36
- Pressure_Level
Description: Pressure Levels of Profiles
Dimensions: (Band_Number)
Data Values: 05., 10., 20., 30., 50., 70., 100., 150., 200.,
250., 300., 400., 500., 620., 700., 780., 850., 920., 950., 1000.
Units: hPa
Cloud_Mask Bit-Field Interpretation
The Cloud_Mask SDS is copied from a portion of the complete MODIS Cloud Mask
SDS in the MOD35_L2 Product.
The 1-km cloud mask is remapped to the 5-km grid by using only the center 1km pixel
in the 5x5 pixel retreival array.
Individual bits or groups of bits in the mask are set to
denote various cloud conditions and characteristics for that pixel.
All bit and byte numbering, in the table below, will start with 0.
Cloud_Mask Bit-Field Interpretation
|
Byte #0 (Cloud Mask & Processing Path Flags)
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
Cloud Mask Flag |
0 = Not Determined 1 = Determined |
1-2 |
Unobstructed FOV Quality Flag |
0 = Confident Cloudy
1 = Probably Cloudy
2 = Probably Clear
3 = Confident Clear |
3 |
Day/Night Flag |
0 = Night
1 = Day |
4 |
Sunglint Flag |
0 = Yes
1 = No |
5 |
Snow/Ice Background Flag |
0 = Yes
1 = No |
6-7 |
Land/Water Background Flag |
0=Water
1=Coastal
2=Desert
3=Land |
Quality_Assurance Bit-Field Interpretation
Each pixel in the Quality_Assurance SDS is assigned a 10 byte (80 bit) array.
Individual bits or groups of bits are set to
denote various quality run-time characteristics for that pixel.
All bit and byte numbering, in the table below, will start with 0.
Quality_Assurance Bit-Field Interpretation
|
Byte #0
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
Retrieved Temperature Profile QA |
0 = Not Useful 1 = Useful |
1-2 |
Retrieved Temperature Profile Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
3 |
(spare) |
n/a |
4 |
Retrieved Moisture Profile QA |
0 = Not Useful 1 = Useful |
5-6 |
Retrieved Moisture Profile Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
7 |
(spare) |
n/a |
Byte #1
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
Total Ozone Burden QA |
0 = Not Useful 1 = Useful |
1-2 |
Total Ozone Burden Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
3 |
(spare) |
n/a |
4 |
Lifted Index Stability QA |
0 = Not Useful 1 = Useful |
5-6 |
Lifted Index Stability Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
7 |
(spare) |
n/a |
Byte #2
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
K Index Stability QA |
0 = Not Useful 1 = Useful |
1-2 |
K Index Stability Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
3 |
(spare) |
n/a |
4 |
Total Totals Stability QA |
0 = Not Useful 1 = Useful |
5-6 |
Total Totals Stability Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
7 |
(spare) |
n/a |
Byte #3
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Cloudy Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #4
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Clear Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #5
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Missing Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #6
|
Bits |
Field Description |
Bit Interpretation Key |
0-1 |
Method of Profile Retrieval |
0 = Statistical
1 = Physical
2 = Other
3 = No Retrieval |
2-3 |
Method of Ozone Retrieval |
0 = RTE Perturbation
1 = Upper and Lower Stratospheric Ozone Method
2 = Other
3 = No Retrieval |
4-7 |
(spares) |
n/a |
Byte #7
|
Bits |
Field Description |
Bit Interpretation Key |
0-1 |
Guess Moisture Profile Source |
0 = NCEP
1 = DAO
2 = AIRS/AMSU
3 = Not Used |
2-3 |
Guess Temperature Profile Source |
0 = NCEP
1 = DAO
2 = AIRS/AMSU
3 = Not Used |
4-5 |
Surface Temperature over Land |
0 = NCEP
1 = DAO
2 = Other
3 = Not Used |
6-7 |
Surface Temperature over Ocean |
0 = Reynolds blended
1 = DAO
2 = Other
|
Byte #8
|
Bits |
Field Description |
Bit Interpretation Key |
0-1 |
Surface Pressure |
0 = NCEP
1 = DAO
2 = Other
3 = Not Used |
2-3 |
Ocean Profile First Guess |
0 = TOMS
1 = TOVS
2 = DAO
3 = Other |
4-7 |
(spares) |
n/a |
Byte #9
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
(spares) |
n/a |
Quality_Assurance_Infrared Bit-Field Interpretation
Each pixel in the Quality_Assurance_Infrared SDS is assigned a 5 byte (40 bit) array.
Individual bits or groups of bits are set to
denote various quality run-time characteristics for that pixel.
All bit and byte numbering, in the table below, will start with 0.
Quality_Assurance_Infrared Bit-Field Interpretation
|
Byte #0
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
IR Water Vapor QA |
0 = Not Useful 1 = Useful |
1-2 |
IR Water Vapor Confidence QA |
0 = Lowest Confidence
1 = Intermediate Confidence
2 = High Confidence
3 = Highest Confidence |
3-7 |
(spares) |
n/a |
Byte #1
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Cloudy Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #2
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Clear Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #3
|
Bits |
Field Description |
Bit Interpretation Key |
0-7 |
Number of Missing Pixels within 5x5 km box |
valid range: 0 to 25 |
Byte #4
|
Bits |
Field Description |
Bit Interpretation Key |
0 |
IR Water Vapor Retrieval Method Used |
0 = Split Window (11-12)
1 = Moisture Profile Integration
2 = Other
3 = No Retrieval |
1-7 |
(spares) |
n/a |
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