A cloudy day in April 2005 is represented with general clarity in this global granule of MYD09CMG. A broad pixel resolution of 5600-m is especially workable in climate models. The slashes of black between overpasses are likely to be filled in by the next day's acquisition.
The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption. Low-level data are corrected for atmospheric gases and aerosols, yielding a level-2 basis for several higher-order gridded level-2 (L2G) and level-3 products.
MYD09CMG provides Bands 1–7 in a daily level-3 product gridded on a simple 0.05 degree (5600-meter) Geographic projection. Data for each pixel is selected on the basis of low solar zenith angle, minimum Band 3 (blue) reflectance, and absence of cloud from level-3 intermediate files. Science Data Sets provided for this product include reflectance values for Bands 1–7, brightness temperatures for Bands 20, 21, 31, and 32, solar and view zenith angles, relative azimuth angle, ozone, granule time, and quality assessment.
Version-5 MODIS/ Aqua Surface Reflectance products are Validated Stage 2, meaning that accuracy has been assessed over a widely distributed set of locations and time periods via several ground-truth and validation efforts.
See Product Description
Science Data Sets for MODIS Aqua Surface Reflectance Daily L3 Global 0.05Deg CMG V005 (MYD09CMG):
Science Data Sets (HDF Layers) (21)
MULTIPLY BY SCALE FACTOR
|Coarse Resolution Surface Reflectance Band 1 (620–670 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Surface Reflectance Band 2 (841–876 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Surface Reflectance Band 3 (459–479 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Surface Reflectance Band 4 (545-565 nm)||Reflectance||16-bit signed integer||-28672||-100 - 16000||0.0001|
|Coarse Resolution Surface Reflectance Band 5 (1230–1250 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Surface Reflectance Band 6 (1628–1652 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Surface Reflectance Band 7 (2105–2155 nm)||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution Solar Zenith Angle||Degree||16-bit signed integer||0||0–18000||0.01|
|Coarse Resolution View Zenith Angle||Degree||16-bit signed integer||0||0–18000||0.01|
|Coarse Resolution Relative Azimuth Angle||Degree||16-bit signed integer||0||-18000–180000||0.01|
|Coarse Resolution Ozone||cm atm||8-bit unsigned integer||0||0–255||0.04|
|Coarse Resolution Brightness Temperature Band 20||Kelvin||16-bit unsigned integer||0||0–40000||0.01|
|Coarse Resolution Brightness Temperature Band 21||Kelvin||16-bit unsigned integer||0||0–40000||0.01|
|Coarse Resolution Brightness Temperature Band 31||Kelvin||16-bit unsigned integer||0||0–40000||0.01|
|Coarse Resolution Brightness Temperature Band 32||Kelvin||16-bit unsigned integer||0||0–40000||0.01|
|Coarse Resolution Granule Time||HHMM||16-bit signed integer||0||0–2355||1.0|
|Coarse Resolution Band 3 Path Radiance||Reflectance||16-bit signed integer||-28672||-100–16000||0.0001|
|Coarse Resolution QA||Bit Field||32-bit unsigned integer||0||0–1073741824||na|
|Coarse Resolution Internal CM||Bit Field||16-bit unsigned integer||0||0–8191||na|
|Coarse Resolution State QA||Bit Field||16-bit unsigned integer||0||0–65535||na|
|N pixels averaged||none||8-bit unsigned integer||0||0–40||na|
The QA information below is excerpted from an HDF-EOS file of the MODIS Surface Reflectance product MOD09CMG.
The V005 MOD09CMG product includes two QA layers, one relating band specific quality (Table 1), and the other presenting the surface reflectance state (Table 2).
Table 1: MYD09CMG.005 0.05 Deg CMG
Surface Reflectance Data QA Descriptions (32-bit)
Coarse Resolution QA
|31||adjacency correction performed||1||yes|
|30||atmospheric correction performed||1||yes|
|26–29||band 7 data quality four bit range||0000||highest quality|
|1000||dead detector; data interpolated in L1B|
|1001||solar zenith >= 86 degrees|
|1010||solar zenith >= 85 and < 86 degrees|
|1100||internal constant used in place of climatological data for at least one atmospheric constant|
|1101||correction out of bounds pixel constrained to extreme allowable value|
|1110||L1B data faulty|
|1111||not processed due to deep ocean or clouds|
|22–25||band 6 data quality four bit range||SAME AS BAND ABOVE|
|18–21||band 5 data quality four bit range||SAME AS BAND ABOVE|
|14–17||band 4 data quality four bit range||SAME AS BAND ABOVE|
|10–13||band 3 data quality four bit range||SAME AS BAND ABOVE|
|6–9||band 2 data quality four bit range||SAME AS BAND ABOVE|
|2–5||band 1 data quality four bit range||SAME AS BAND ABOVE|
|0–1||MODLAND QA bits||00||corrected product produced at ideal quality all bands|
|01||corrected product produced at less than ideal quality some or all bands|
|10||corrected product not produced due to cloud effects all bands|
|11||corrected product not produced due to other reasons some or all bands may be fill value [Note that a value of (11) overrides a value of (01)].|
Table 2: MYD09CMG.005 0.05 Deg CMG Surface Reflectance Data State QA Descriptions (16-bit)
Bits are listed from the MSB (bit 15) to the LSB (bit 0)
Coarse Resolution State QA
|15||internal snow algorithm flag||1||yes|
|14||BRDF correction performed||1||yes|
|13||Pixel is adjacent to cloud||1||yes|
|12||MOD35 snow/ice flag||1||yes|
|11||internal fire algorithm flag||1||fire|
|10||internal cloud algorithm flag||1||cloud|
|3–5||land/water flag||000||shallow ocean|
|010||ocean coastlines and lake shorelines|
|011||shallow inland water|
|101||deep inland water|
|11||not set, assumed clear|
|Temporal Coverage:||July 4, 2002 -|
|File Size:||~985 MB|
|Dimensions:||3600 x 7200 rows/columns|
|Resolution:||0.05 degrees (5600 meters)|
|Science Data Sets (SDS HDF Layers):||21|
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