Aqua MODIS land surface temperature data from the MYD11A2 product over Tibet, July 4 - 11, 2018.View full-size image
The MYD11A2 Version 6 product provides an average 8-day per-pixel Land Surface Temperature and Emissivity (LST&E) with a 1 kilometer (km) spatial resolution in a 1,200 by 1,200 km grid. Each pixel value in the MYD11A2 is a simple average of all the corresponding MYD11A1 LST pixels collected within that 8-day period. The 8-day compositing period was chosen because twice that period is the exact ground track repeat period of the Terra and Aqua platforms. Provided along with the daytime and nighttime surface temperature bands are associated quality control assessments, observation times, view zenith angles, and clear-sky coverages along with bands 31 and 32 emissivities from land cover types.
|File Size||~3.86 MB|
|Temporal Extent||2002-07-04 to Present|
|Geographic Dimensions||1200 km x 1200 km|
|Number of Science Dataset (SDS) Layers||12|
|Columns/Rows||1200 x 1200|
|Pixel Size||1000 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor||Additional Offset|
|LST_Day_1km||Day Land Surface Temperature||Kelvin||16-bit unsigned integer||0||N/A||7500 to 65535||0.02||N/A|
|QC_Day||Daytime LST Quality Indicators||Bit Field||8-bit unsigned integer||N/A||N/A||0 to 255||N/A||N/A|
|Day_view_time||Local time of day observation||Hours||8-bit unsigned integer||255||N/A||0 to 240||0.1||N/A|
|Day_view_angl||View zenith angle of day observation||Degree||8-bit unsigned integer||255||N/A||0 to 130||N/A||-65|
|LST_Night_1km||Night Land Surface Temperature||Kelvin||16-bit unsigned integer||0||N/A||7500 to 65535||0.02||N/A|
|QC_Night||Nighttime LST Quality indicators||Bit Field||8-bit unsigned integer||N/A||N/A||0 to 255||N/A||N/A|
|Night_view_time||Local time of night observation||Hours||8-bit unsigned integer||255||N/A||0 to 240||0.1||N/A|
|Night_view_angl||View zenith angle of night observation||Degree||8-bit unsigned integer||255||N/A||0 to 130||N/A||-65|
|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||N/A||8-bit unsigned integer||0||N/A||1 to 255||0.002||0.49|
|Clear_sky_days||Day clear-sky coverage||Bit Field||8-bit unsigned integer||0||N/A||1 to 255||N/A||N/A|
|Clear_sky_nights||Night clear-sky coverage||Bit Field||8-bit unsigned integer||0||N/A||1 to 255||N/A||N/A|
The Quality Control (QC) layers are 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 layers.
The QA bit flags for the QC layers are provided in the User Guide in Table 13 on page 21.
Please note that whenever the Mandatory QA flags (bits 0-1) have a value of 2 (decoded to 10) or 3 (decoded to 11), LST is not produced due to cloud effects or other reasons. Under these conditions, all remaining QA bits and SDS layers are undefined (although bit flags display as 00).
Quality assurance information should be considered when determining the usability of data for a particular science application. The ArcGIS MODIS-VIIRS Python Toolbox contains tools capable of decoding quality data layers while producing thematic quality raster files for each quality attribute.
In addition to data access and transformation processes, AppEEARS also has the capability to unpack and interpret the quality layers.
For complete information about the MYD11A2 known issues please refer to the MODIS Land Quality Assessment website.