MYD21 v006

MODIS/Aqua Land Surface Temperature/3-Band Emissivity 5-Min L2 1 km


PI: Glynn C. Hulley

Description

The MYD21 Land Surface Temperature and Emissivity (LST&E) 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 Land Surface Temperature (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 dynamically retrieve both LST and spectral emissivity simultaneously from the 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 two 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).

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Characteristics

Product Maturity

Aqua MODIS LST&E products are validated to stage 1 maturity level.

Collection and Granule

Collection

Characteristic Description
CollectionAqua MODIS
DOI10.5067/MODIS/MYD21.006
File Size~4 MB
Temporal ResolutionDaily
Temporal Extent2002-07-04 to Present
Spatial ExtentGlobal
Coordinate SystemNone (Swath)
DatumN/A
File FormatHDF-EOS
Geographic Dimensions2300 km x 2300 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers15
Columns/RowsVaries by scene
Pixel Size1000 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor Additional Offset
LST Land surface temperature Kelvin 16-bit unsigned integer 0 N/A 7500 to 65535 0.02 N/A
QC Quality Control (QC) for LST and emissivity N/A 16-bit unsigned integer N/A N/A 0 to 65535 N/A N/A
Emis_29 Band 29 emissivity N/A 8-bit unsigned integer 0 N/A 1 to 255 0.002 0.49
Emis_31 Band 31 emissivity N/A 8-bit unsigned integer 0 N/A 1 to 255 0.002 0.49
Emis_32 Band 32 emissivity Select Units 8-bit unsigned integer 0 N/A 1 to 255 0.002 0.49
LST_err Land surface temperature error Kelvin 8-bit unsigned integer 0 N/A 1 to 255 0.04 N/A
Emis_29_err Band 29 emissivity error N/A 16-bit unsigned integer 0 N/A 1 to 65535 0.0001 N/A
Emis_31_err Band 31 emissivity error N/A 16-bit unsigned integer 0 N/A 1 to 65535 0.0001 N/A
Emis_32_err Band 32 emissivity error N/A 16-bit unsigned integer 0 N/A 1 to 65535 0.0001 N/A
View_angle MODIS view angle for current pixel Degree 8-bit unsigned integer N/A N/A 0 to 180 0.5 N/A
Emis_ASTER ASTER Global Emissivity Dataset (GED) emissivity N/A 8-bit unsigned integer 0 N/A 1 to 255 0.002 0.49
PWV Precipitable water vapor cm 16-bit unsigned integer N/A N/A 0 to 65535 0.001 N/A
oceanpix Ocean-land mask N/A 8-bit unsigned integer N/A N/A 0 to 1 N/A N/A
Latitude Pixel latitude Degree 32-bit floating point 999.99 N/A -90 to 90 N/A N/A
Longitude Pixel longitude Degree 32-bit floating point 999.99 N/A -180 to 180 N/A N/A

Ocean-land mask Classes

Value Description
0 Land
1 Water

Product Quality

The Quality Control (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 quality layer.

The bit definition index for the quality layer is available in the User Guide on page 18.

Known Issues

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

Documentation

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MYD21.006

About the Image

Land Surface Temperature (LST) from the MYD21 product over India on September 28, 2018.

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