HLSS30 v002

HLS Sentinel-2 Multi-spectral Instrument Surface Reflectance Daily Global 30m


PI: Jeffrey G. Masek, Junchang Ju

Description

The Harmonized Landsat and Sentinel-2 (HLS) project provides consistent surface reflectance data from the Operational Land Imager (OLI) aboard the joint NASA/USGS Landsat 8 satellite and the Multi-Spectral Instrument (MSI) aboard Europe’s Copernicus Sentinel-2A and Sentinel-2B satellites. The combined measurement enables global observations of the land every 2–3 days at 30-meter (m) spatial resolution. The HLS project uses a set of algorithms to obtain seamless products from OLI and MSI that include atmospheric correction, cloud and cloud-shadow masking, spatial co-registration and common gridding, illumination and view angle normalization, and spectral bandpass adjustment.

The HLSS30 product provides 30-m Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) and is derived from Sentinel-2A and Sentinel-2B MSI data products. The HLSS30 and HLSL30 products are gridded to the same resolution and Military Grid Reference System (MGRS) tiling system, and thus are “stackable” for time series analysis.

The HLSS30 product is provided in Cloud Optimized GeoTIFF (COG) format, and each band is distributed as a separate COG. There are 13 bands included in the HLSS30 product along with four angle bands and a quality assessment (QA) band. See the User Guide for a more detailed description of the individual bands provided in the HLSS30 product.

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Characteristics

Improvements/Changes from Previous Versions

Aerosol QA bits from the USGS Land Surface Reflectance Code (LaSRC) model output have been added into the Function of Mask (Fmask) data layer. The added two bits indicate the aerosol levels: high, medium, low, and climatology aerosol.

Product Maturity

HLS surface reflectance products are currently at stage 1 validation. Stage 2 validation of the HLS products is ongoing and will be made available on the individual data product landing pages when complete.

Collection and Granule

Collection

Characteristic Description
CollectionHLS
DOI10.5067/HLS/HLSS30.002
File Size~20 MB
Temporal ResolutionDaily
Temporal Extent2015-12-01 to Present
Spatial ExtentGlobal (Non-Antarctic)
Coordinate SystemUniversal Transverse Mercator (UTM)
DatumWorld Geodetic System (WGS84)
File FormatGeoTIFF
Geographic Dimensions10980 km x 10980 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers18
Columns/Rows3660 x 3660
Pixel Size30 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
Band 1 Coastal Aerosol N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 2 Blue N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 3 Green N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 4 Red N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 5 Red Edge1 N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 6 Red Edge2 N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 7 Red Edge3 N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 8 NIR Broad N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 8A NIR Narrow N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 9 Water Vapor N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 10 Cirrus N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 11 SWIR1 N/A 16-bit signed integer -9999 N/A N/A 0.0001
Band 12 SWIR2 N/A 16-bit signed integer -9999 N/A N/A 0.0001
Fmask Quality Bits Bit Field 8-bit unsigned integer 255 N/A N/A N/A
SZA Sun Zenith Angle Degree 16-bit unsigned integer 40000 N/A N/A 0.01
SAA Sun Azimuth Angle Degree 16-bit unsigned integer 40000 N/A N/A 0.01
VZA View Zenith Angle Degree 16-bit unsigned integer 40000 N/A N/A 0.01
VAA View Azimuth Angle Degree 16-bit unsigned integer 40000 N/A N/A 0.01

Product Quality

Additional information related to cloud and aerosol quality along with QA mappings are provided under section 6.4 of the User Guide.

Known Issues

The atmospheric correction over bright targets occasionally retrieves unrealistically high aerosol and thus makes the surface reflectance too low. High aerosol retrievals, both false high aerosol and realistically high aerosol, are masked when quality bits 6 and 7 are both set to 1 (see Table 9 in the User Guide); the corresponding spectral data should be discarded from analysis.

Challenges in the acquisition of source input data for the HLSS30 data product have resulted in data gaps and increased latency in delivery of this data product. Work toward a solution is ongoing, but there is currently not a date for when this issue is expected to be resolved.


About the image

HLSS30 bands 4,3,2 showing croplands around Cedar Falls in Northeastern Iowa taken May 26, 2021.

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Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
Earthdata Search Quick Guide

Using the Data

Access Data

Citation

DOI: 10.5067/HLS/HLSS30.002