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MYD21 V006

10.5067/MODIS/MYD21.006
MODIS/Aqua Land Surface Temperature/3-Band Emissivity 5-Min L2 1 km
MYD21

The MYD21 Land Surface Temperature (LST) and Emissivity swath data product is produced daily in five minute temporal increments of satellite acquisition. The swath is approximately 2,030 pixels along track and 1,354 pixels per line, at a nadir resolution of 1,000 meters. The MYD21 LST algorithm differs from the MYD11 algorithm in that the MYD21 LST algorithm is based on the ASTER Temperature Emissivity Separation (TES) technique, whereas the MYD11 uses the split-window technique. The MYD21 TES algorithm uses a physics-based algorithm to retrieve dynamically both the LST and Emissivity simultaneously from the three MODIS thermal infrared bands 29, 31, and 32. The TES algorithm is combined with an improved Water Vapor Scaling (WVS) atmospheric correction scheme to stabilize the retrieval during very warm and humid conditions. MYD21 products are available 2 months after acquisition due to latency of data inputs. Additional details regarding the method used to create this Level 2 (L2) product are available in the Algorithm Theoretical Basis Document (ATBD).

Collection

Characteristic Description
Temporal Granularity Daily
Temporal Extent 2002-07-04 to Present
Spatial Extent Global
File Size ~4 MB
Coordinate System None (Swath)
Datum N/A
File Format HDF-EOS
Geographic Dimensions 2300 km x 2300 km

 

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers 15
Columns/Rows Varies by scene
Pixel Size 1000 m

 

Data Layer Characteristics

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
LST

Land surface temperature

Kelvin 16-bit unsigned integer

0

N/A

7500 to 65535

0.02
QC

Quality Control (QC) for LST and emissivity

N/A 16-bit unsigned integer

N/A

N/A

0 to 65535

N/A
Emis_29

Band 29 emissivity

N/A 8-bit unsigned integer

0

N/A

1 to 255

0.002
Emis_31

Band 31 emissivity

N/A 8-bit unsigned integer

0

N/A

1 to 255

0.002
Emis_32

Band 32 emissivity

Select Units 8-bit unsigned integer

0

N/A

1 to 255

0.002
LST_err

Land surface temperature error

Kelvin 8-bit unsigned integer

0

N/A

1 to 255

0.04
Emis_29_err

Band 29 emissivity error

N/A 16-bit unsigned integer

0

N/A

1 to 65535

0.0001
Emis_31_err

Band 31 emissivity error

N/A 16-bit unsigned integer

0

N/A

1 to 65535

0.0001
Emis_32_err

Band 32 emissivity error

N/A 16-bit unsigned integer

0

N/A

1 to 65535

0.0001
View_angle

MODIS view angle for current pixel

Degree 8-bit unsigned integer

N/A

N/A

0 to 180

0.5
Emis_ASTER

ASTER Global Emissivity Dataset (GED) emissivity 

N/A 8-bit unsigned integer

0

N/A

1 to 255

0.002
PWV

Precipitable water vapor

cm 16-bit unsigned integer

N/A

N/A

0 to 65535 

0.001
oceanpix

Ocean-land mask

N/A 8-bit unsigned integer

N/A

N/A

0 to 1

N/A
Latitude

Pixel latitude

Degree 32-bit floating point

999.99

N/A

-90 to 90

N/A
Longitude

Pixel longitude

Degree 32-bit floating point

999.99

N/A

-180 to 180

N/A

 

Product Quality

The QC layer is stored in an efficient bit-encoded manner. The unpack_sds_bits executable from the LDOPE Tools is available to the user community to help parse and interpret the QC layer.

The bit definition index for the QC layer is available in the User Guide on page 17.

 

Known Issues

For complete information about the MYD21 known issues please refer to the MODIS Land Quality Assessment website.

MYD21 V006

MYD21. Acquired March 15, 2014. Northeast United States.

PI Name: 
Glynn C. Hulley
Other Tools: 
Decommissioned: 
False