MODIS/Terra MOD21: Land Surface Temperature and Emissivity at 1km Resolution

MODIS/Terra MOD21 Version 6 data products were decommissioned on July 31, 2023. This daily, 5-minute increment swath product provides land surface temperature and emissivity at a 1,000-meter nadir resolution using a physics-based Temperature/Emissivity Separation algorithm. The product was created by the National Aeronautics and Space Administration but has known issues with high-temperature outliers, especially over desert regions.

Use Cases

• Monitoring daily land surface temperature dynamics based on 5-minute temporal increments.
• Analyzing spectral emissivity variations across landscapes using retrieved data from MODIS thermal bands 29, 31, and 32.
• Studying surface thermal anomalies like fires or lava flows where high-temperature outlier thresholds are not applied.
• Comparing TES-based retrieval performance against split-window technique products like MOD11.
• Investigating atmospheric correction impacts on temperature stability during warm, humid conditions using the Water Vapor Scaling scheme.

Strengths

• Provides simultaneous retrieval of both land surface temperature and spectral emissivity using a physics-based TES algorithm.
• Offers daily data in five-minute temporal increments of satellite acquisition.
• Swath dimensions are approximately 2,030 pixels along track and 1,354 pixels per line.
• Includes an improved Water Vapor Scaling atmospheric correction scheme for stabilization.

Limitations

• The Version 6 product is decommissioned; users are directed to use the MOD21 Version 6.1 product.
• Known to have increased occurrences of extreme high-temperature outliers, particularly over deserts, due to undetected cloud and dust.
• Contaminated pixel values are retained in the output, requiring users to apply Quality Control filtering, unlike in heritage products where they were flagged and filled.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Produced from MODIS/Terra satellite acquisitions using the MOD21 Land Surface Temperature and Emissivity algorithm.

Time Range

Daily production; products were available with a two-month latency after acquisition.

Freshness

Last updated 2026-03-12 23:42:03.865214; however, the specific data product version was decommissioned in 2023.

Geography

Global coverage from the Terra satellite's swath.