Landsat Collection 2 Level-2 Surface Temperature

Date modified: 14 February 2022

Product overview

Background

Digital Earth Africa (DE Africa) provides free and open access to a copy of Landsat Collection 2 Level-2 products over Africa. These products are produced and provided by the United States Geological Survey (USGS).

The Landsat series of Earth Observation satellites, jointly led by USGS and NASA, have been continuously acquiring images of the Earth’s land surface since 1972. DE Africa provides data from Landsat 5, 7, 8, and 9 satellites, including historical observations dating back to late 1980s and regularly updated new acquisitions.

New Level-2 Landsat 7, 8, and 9 data are available after approximately 25, 15, and 3 days, respectively, from acquisition. See Landsat Collection 2 Generation Timeline for details.

USGS Landsat Collection 2 was released early 2021 and offers improved processing, geometric accuracy, and radiometric calibration compared to previous Collection 1 products. The Level-2 products are endorsed by the Committee on Earth Observation Satellites (CEOS) to be Analysis Ready Data (CARD)-compliant. This internationally-recognised certification ensures these products have been processed to a minimum set of requirements and organised into a form that allows immediate analysis with a minimum of additional user effort and interoperability both through time and with other datasets.

USGS Landsat Collection 2 Level-2 includes:

• Surface Reflectance

• Surface Temperature

This document provides technical specifications for the Surface Temperature product. Information for the Surface Refletance product can be found in the Landsat Collection 2 Level-2 Surface Reflectance specification.

Surface temperature measures the Earth’s surface temperature and is an important geophysical parameter in global energy balance studies and hydrologic modeling. Surface temperature is also useful for monitoring crop and vegetation health, and extreme heat events such as natural disasters (e.g., volcanic eruptions, wildfires), and urban heat island effects.

A Jupyter Notebook which demonstrates loading and using Landsat surface temperature products in the Sandbox is also available.

Specifications

Spatial and temporal coverage

DE Africa provides Landsat Collection 2 Level-2 from Landsat 5, 7, 8, and 9 as seperate products. Relevant coverage and metadata can be viewed on DE Africa Metadata Exploer:

• Landsat 5 Collection 2 Level-2 Surface Temperature

• Landsat 7 Collection 2 Level-2 Surface Temperature

• Landsat 8 Collection 2 Level-2 Surface Temperature

• Landsat 9 Collection 2 Level-2 Surface Temperature

Table 1: Landsat Collection 2 Level-2 Surface Temperature product specifications

Satellite	Landsat 5	Landsat 7	Landsat 8	Landsat 9
Instrument	Multispectral Scanner (MSS), Thematic Mapper (TM)	Enhanced Thematic Mapper (ETM+)	Operational Land Imager (OLI), Thermal Infrared Sensor (TIRS)	OLI-2, TIRS-2
Number of bands	10	10	10	10
Cell size - X (metres)	30	30	30	30
Cell size - Y (metres)	30	30	30	30
Coordinate reference system	Universal Transverse Mercator (UTM)	UTM	UTM	UTM
Temporal resolution	Every 16 days	Every 16 days	Every 16 days	Every 16 days
Temporal range	1984 – 2012	1999 – present	2013 – present	2021 – present
Parent dataset	Landsat Collection 2 Level-1	Landsat Collection 2 Level-1	Landsat Collection 2 Level-1	Landsat Collection 2 Level-1
Update frequency	NA (archive)	Daily	Daily	Daily

Measurements

Table 2: Landsat 5 and Landsat 7 Surface Temperature Level-2 measurements

Band ID	Description	Units	Range	Data type	No data\(^\dagger\)	Conversion\(^\ddagger\)
ST_B6	Surface temperature band 6 (Thermal Infrared (TIR))	Kelvin	1-65535	uint16	0	0.00341802 * DN + 149.0
ST_TRAD	Thermal radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-22000	int16	-9999	0.001 * DN
ST_URAD	Upwell radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-28000	int16	-9999	0.001 * DN
ST_DRAD	Downwell radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-28000	int16	-9999	0.001 * DN
ST_ATRAN	Atmospheric transmittance	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_EMIS	Emissivity	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_EMSD	Emissivity standard deviation	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_CDIST	Distance to cloud	Kilometers	0-24000	int16	-9999	0.01 * DN
QA_PIXEL	Pixel quality	Bit Index	0-65535	uint16	1	NA
QA_RADSAT	Radiometric saturation	Bit Index	0-65535	uint16	0	NA
ST_QA	Surface temperature uncertainty	Kelvin	0-32767	int16	-9999	0.01 * DN

\(^\dagger\) No data or fill value.

\(^\ddagger\) Physical measurement can be derived from the Digital Number (DN) stored in the product using the conversion equation listed.

More inforamtion can be found from the Landsat 4-7 Collection 2 Science Product Guide.

Table 3: Landsat 8 and Landsat 9 Level-2 Surface Temperature measurements

Landsat 8 and Landsat 9 Level-2 science products are generated using a different algorithm and have different output measurements compared to Landsat 5 and Landsat 7.

Band ID	Description	Units	Range	Data type	No data\(^\dagger\)	Conversion\(^\ddagger\)
ST_B10	Surface temperature band 10 (TIR)	Kelvin	1-65535	uint16	0	0.00341802 * DN + 149.0
ST_TRAD	Thermal radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-22000	int16	-9999	0.001 * DN
ST_URAD	Upwell radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-28000	int16	-9999	0.001 * DN
ST_DRAD	Downwell radiance	Wm\(^{-2}\)sr\(^{-1}\)\(\mu\)m\(^{-1}\)	0-28000	int16	-9999	0.001 * DN
ST_ATRAN	Atmospheric transmittance	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_EMIS	Emissivity	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_EMSD	Emissivity standard deviation	Unitless	0-10000	int16	-9999	0.0001 * DN
ST_CDIST	Distance to cloud	Kilometers	0-24000	int16	-9999	0.01 * DN
QA_PIXEL	Pixel quality	Bit Index	0-65535	uint16	1	NA
QA_RADSAT	Radiometric saturation	Bit Index	0-65535	uint16	0	NA
ST_QA	Surface temperature uncertainty	Kelvin	0-32767	int16	-9999	0.01 * DN

\(^\dagger\) No data or fill value.

\(^\ddagger\) Physical measurement can be derived from the Digital Number (DN) stored in the product using the conversion equation listed.

More inforamtion can be found from Landsat 8 OLI/TIRS Collection 2 Science Product Guide and Landsat 8-9 OLI/TIRS Collection 2 Level 2 Data Format Control Book

Quality assessment bands

Pixel quality assessment (QA_PIXEL) bands are generated by the CFMask algorithm. Different bit definitions are used because the cirrus band is only available on Landsat 8 and 9. This band is relevant to both Surface Reflectance and Surface Temperature products.

Table 4: Pixel quality assessment (QA_PIXEL) bit index.

Bit	Landat 5 & 7	Landsat 8 & 9	Description Values
0	Fill	Fill	0 for image data; 1 for fill data
1	Dilated Cloud	Dilated Cloud	0 for cloud is not dilated or no cloud; 1 for cloud dilation
2	Unused	Cirrus	0 for cirrus confidence is not; 1 for high confidence cirrus
3	Cloud	Cloud	0 for cloud confidence is not high; 1 for high confidence cloud
4	Cloud Shadow	Cloud Shadow	0 for Cloud Shadow Confidence is not high; 1 for high confidence cloud shadow
5	Snow	Snow	0 for Snow/Ice Confidence is not high; 1 for high confidence snow cover
6	Clear	Clear	0 if Cloud or Dilated Cloud bits are set; 1 if Cloud and Dilated Cloud bits are not set
7	Water	Water	0 for land or cloud; 1 for water
8-9	Cloud Confidence	Cloud Confidence	00 for no confidence level set; 01 Low confidence; 10 Medium confidence; 11 High confidence
10-11	Cloud Shadow Confidence	Cloud Shadow Confidence	00 for no confidence level set; 01 Low confidence; 10 Reserved; 11 High confidence
12-13	Snow/Ice Confidence	Snow/Ice Confidence	00 for no confidence level set; 01 Low confidence; 10 Reserved; 11 High confidence
14-15	Unused	Cirrus Confidence	00 for no confidence level set; 01 Low confidence; 10 Reserved; 11 High confidence

Radiometric saturation quality assessment (QA_RADSAT) bands are different for Landsat 5, 7 and 8/9 because the sensors have different spectral bands. This band is relevant to both Surface Reflectance and Surface Temperature products.

Table 5: Radiometric saturation quality assessment (QA_RADSAT) bit index.

Bit	Landsat 5	Landsat 7	Landsat 8 & 9	Description Values
0	Band 1 (Blue)	Band 1 (Blue)	Band 1 (Coastal)	0 no saturation; 1 saturated data
1	Band 2 (Green)	Band 2 (Green)	Band 2 (Blue)	0 no saturation; 1 saturated data
2	Band 3 (Red)	Band 3 (Red)	Band 3 (Green)	0 no saturation; 1 saturated data
3	Band 4 (NIR)	Band 4 (NIR)	Band 4 (Red)	0 no saturation; 1 saturated data
4	Band 5 (SWIR1)	Band 5 (SWIR1)	Band 5 (NIR)	0 no saturation; 1 saturated data
5	Band 6 (TIR)	Band 6L (TIR)†	Band 6 (SWIR1)	0 no saturation; 1 saturated data
6	Band 7 (SWIR2)	Band 7 (SWIR2)	Band 7 (SWIR2)	0 no saturation; 1 saturated data
7	Unused	Unused	Unused	0
8	Unused	Band 6H (TIR)‡	Band 9 (Cirrus)	0 no saturation; 1 saturated data
9	Dropped Pixel	Dropped Pixel	Unused	0 Pixel present; 1 detector doesn’t have a value - no data
10	Unused	Unused	Unused	0
11	Unused	Unused	Terrain occlusion	0 no terrain occlusion; 1 terrain occlusion
12	Unused	Unused	Unused	0
13	Unused	Unused	Unused	0
14	Unused	Unused	Unused	0
15	Unused	Unused	Unused	0

\(^\dagger\), \(^\ddagger\) For Landsat 7 products, the Band 6 TOA brightness temperature product is generated from ETM+ Band 6 High gain (6H) and Band 6 Low gain (6L) merged together. The merged Band 6 is comprised of pixels that are not saturated in Band 6H. When Band 6H pixels are saturated with a brightness temperature outside of the 6H dynamic range (from 240K to 322K), they will be filled with pixels from the 6L band even if those pixels are saturated.

Processing

Landsat Collection 2 Level-2 products are processed by the USGS from Collection 2 Level-1 inputs. Landsat 5, 7, 8, and 9 surface temperature products are generated using the Landsat surface temperature algorithm.

Media and example images

Figure 1: Landsat false color composites (highlighting vegetation, top row) and corresponding surface temperature measurements (in Kelvin, bottom row) over an area in Tripoli District, Libya.

Related services

• Landsat Collection 2 Level-2 Surface Reflectance

References

• USGS Collection Level-2 website

• Landsat 8-9 OLI/TIRS Collection 2 Level-2

• Landsat 7 ETM+ Collection 2 Level-2

• Landsat 4-5 TM Collection 2 Level-2

License

There are no restrictions on Landsat data downloaded from the USGS; it can be used or redistributed as desired. USGS request that you include a statement of the data source when citing, copying, or reprinting USGS Landsat data or images.

Acknowledgements

Landsat Level- 2 Surface Temperature Science Product courtesy of the U.S. Geological Survey.

Data access

Amazon Web Services S3

Landsat Collection 2 Level-2 is available in AWS S3, sponsored by the Public Dataset Program.

Table 6: AWS data access details.

AWS S3 details
Bucket ARD	arn:aws:s3:::deafrica-landsat
Region	af-south-1

The bucket is in the AWS region af-south-1 (Cape Town). Additional region specifications can be applied as follows:

aws s3 ls --region=af-south-1 s3://deafrica-landsat/

The file paths follow the format collection02/level-2/standard/<sensor>/<year>/<path>/<row>/<scene_id>/.

Table 7: AWS file path convention.

File path element	Description	Example
sensor	Landsat sensor name, tm, etm or oli-tirs for landsat 5, 7 and 8/9	oli-tirs
year	Observation year	2021
path	Landsat orbit path id	172
row	Landsat orbit row id	057
scene_id	Landsat scene id	LC08_L2SP_172057_20210101_20210308_02_T1

OGC Web Services (OWS)

This product is available through DE Africa’s OWS.

Table 8: OWS data access details.

OWS details
Name	DE Africa Services
Web Map Services (WMS) URL	https://ows.digitalearth.africa/wms?version=1.3.0
Web Coverage Service (WCS) URL	https://ows.digitalearth.africa/wcs?version=2.1.0
Layer name	ls5_st, ls7_st, ls8_st, ls9_st

Digital Earth Africa OWS details can be found at https://ows.digitalearth.africa/.

For instructions on how to connect to OWS, see this tutorial.

Open Data Cube (ODC)

The Landsat Collection 2 Level-2 products can be accessed through the Digital Earth Africa ODC API, which is available through the Digital Earth Africa Sandbox.

ODC product names: ls5_st, ls7_st, ls8_st, ls9_st

Specific bands of data can be called by using either the default names or any of a band’s alternative names, as listed in the table below. ODC Datacube.load commands without specified bands will load all bands.

Table 9: Landsat 5 and Landsat 7 Level-2 Surface Temperature (ODC product ls5_st and ls7_st) band names.

Band name	Alternative names	Fill value
ST_B6	band_6, st, surface_temperature	0
ST_TRAD	trad, thermal_radiance	-9999
ST_URAD	urad, upwell_radiance	-9999
ST_DRAD	drad, downwell_radiance	-9999
ST_ATRAN	atran, atmospheric_transmittance	-9999
ST_EMIS	emis, emissivity	-9999
ST_EMSD	emsd, emissivity_stddev	-9999
ST_CDIST	cdist, cloud_distance	-9999
QA_PIXEL	pq, pixel_quality	1
QA_RADSAT	radsat, radiometric_saturation	0
ST_QA	st_qa, surface_temperature_quality	-9999

Table 10: Landsat 8 and Landsat 9 Level-2 Surface Temperature (ODC product ls8_st and ls9_st) band names.

Band name	Alternative names	Fill value
ST_B10	band_10, st, surface_temperature	0
ST_TRAD	trad, thermal_radiance	-9999
ST_URAD	urad, upwell_radiance	-9999
ST_DRAD	drad, downwell_radiance	-9999
ST_ATRAN	atran, atmospheric_transmittance	-9999
ST_EMIS	emis, emissivity	-9999
ST_EMSD	emsd, emissivity_stddev	-9999
ST_CDIST	cdist, cloud_distance	-9999
QA_PIXEL	pq, pixel_quality	1
QA_RADSAT	radsat, radiometric_saturation	0
ST_QA	st_qa, surface_temperature_quality	-9999

Band names are case-sensitive.

For examples on how to use the ODC API, see the DE Africa example notebook repository.

Technical information

Surface Temperature

The surface temperature product is generated from the Landsat Collection 2 Level-1 thermal infrared bands, Top of Atmosphere (TOA) reflectance, TOA brightness temperature, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Emissivity Database (GED) data, ASTER Normalized Difference Vegetation Index (NDVI) data, and atmospheric profiles of geopotential height, specific humidity, and air temperature extracted from Goddard Earth Observing System (GEOS) Model Version 5 Forward Processing Instrument Teams (FP-IT) (for acquisitions from 2000 to present) or Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) (for acquisitions from 1982 to 1999).

For more information and caveats of the product, visit the Landsat Collection 2 Surface Temperature webpage.

The surface temperature product is provided at 30 m spatial sampling, however, the thermal sensors vary in spectral response, sensitivity and resolution.

Table 11: Landsat thermal sensors specification.

Satellite	Sensor	Spetral Band	Wavelength (µm)	Spatial Resolution (m)
Landsat 8/9	Thermal Infrared Sensor (TIRS)/TIRS-2	10	10.60 - 11.19	100
		11	11.50 - 12.51	100
Landsat 7	Enhanced Thematic Mapper Plus (ETM+)	6	10.31 - 12.36	60
Landsat 5	Thematic Mapper (TM)	6	10.40 - 12.50	120

The Level-2 product provides a number of intermediate and quality bands for surface temperature measurement. These bands may help interpret the results.

Table 12: Surface temperature relevant bands.

Name	Explanation
Surface temperature (ST)	The temperature of the Earth’s surface in Kelvin (K).
Thermal radiance (ST_TRAD)	The values produced when thermal band reflectance is converted to radiance.
Upwell radiance (ST_URAD)	The amount of electromagnetic radiation reflected upward from the ground’s surface.
Downwellradiance (ST_DRAD)	The thermal energy radiated onto the ground by all objects in a hemisphere surrounding it.
Atmospheric transmittance (ST_ATRAN)	The ratio of the transmitted radiation to the total radiation incident upon the medium (atmosphere).
Emissivity (ST_EMIS)	The ratio of the energy radiated from a material’s surface to that radiated from a blackbody.
Emissivity_stdev (ST_EMSD)	The extent of deviation of the emissivity product. This layer is used along with cloud_distance to create the quality assessment product.
Distance to cloud (ST_CDIST)	The distance, in kilometers, that a pixel is from the nearest cloud pixel. This layer is used along with emissivity_stdev to create the quality assessment product.
Surface temperature uncertainty (ST_QA)	Provides the Surface Temperature product uncertainty using a combination of uncertainty values and distance to cloud values.